starting over with a efi 401

[crownedclown]

this is what i have- 76 chief currentlly stock 360

i have already purchased-

401 currently torn down
edelbrock pro flo fuel injection
bjs 6" lift
35s
rancho 9000 shocks
dual rancho steering stabalizer
sway disconnects
heavy dutyu-joint steering shaft
sway bushings

what i need is imfo/ list/advice of items to compliment, my intentions r t o have an extremely capable off roader and daily driver. at this point i plan on using 4.10s, pro/cons/suggestions? i also intend on switching to part time 4 wheel drive, what all do i need to do and buy to make this happen? I plan on rebuilding the 401 using the stock crank, pistons, conneccting rods, and heads. What else if any, would be worth re-using, from the stock set-up? in addition i would like some advice on a quality rebuild kit that would compliment my set-up , and where to purchase. r there certain items i should upgrade upon with a particular kit?

ive contacted edelbrock and they suggested aedel. #2132 cam or a comp cams xe256h. hows that sound?

ignition? Headers? air filter? etc. etc.

should i upgrade timing chain to a double roller or gear drive?

how about the timing chain cover (nickel?) ive read about other upgrades as well, true? needed?

water pump?

im sure ive left out tons of stuff , and appreciate any and all suggestions

thankyou
wayne

[JeepinPete]

I'd reconcider changing your Quadratrac to part time. The 401 is going to put out some decent power. That combined with 35's on the stock D44 makes their life iffy at best. With a full time setup, the power the axle is seeing is only half of what it would be in a part time setup. The QT is great for traction, and you are going to need all you can get!

[derf]

ive contacted edelbrock and they suggested aedel. #2132 cam or a comp cams xe256h. hows that sound?

The Summit 2132 is a pretty small cam. It's smaller than a factory stock 401 cam by quite a bit. You'd be choking off the engine if you put it in. It's really only a good fit in the 304.

The 256 is also a little small for a 401, especially with fuel injection. It works better in a 360.

The 401 can take a lot more cam than many people think (even around here). I would recommend you don't go any smaller than a Summit 8600 at least. I'm running a Summit 8601 with my TBI setup and it makes pretty good power from idle to redline.

[Rogue]

i did an comparable to summit 8601 grind w/air gap rpm intake... not enough cam IMHO ;)

it doesn't sounds as though money is an issue soooo.....

- have a custom convertor made that is matched to your final cam selection, gear selection, vehicle weight and your desired throttle response :D ( funny i was just talking about this with a dude i know with an LS6 454 72 chevelle... anyhow... he bought everything in the world and the biggest HP/gas pedal ratio of fun he bought was a 3500 stall convertor :D first thing he said is the thing i always try to tell people, a high stall speed doesn't mean you will do tire lifting launches out of the hole like a drag car, unless of course that is what you wanna do :cool: but then you'd need a transbrake or line lock or something... )

- upgrade to forged pistons. cast pistons are the weakest link of a 401. when i last built a 401 hypereutectic were not availblbe yet - they are a good compromise

- buy a distributor with roller bearings to maintain stable timing events.

- on the Turbo 400 if it still has the weak 18 element or however many elemnt sprag in it you wanna upgrade that as that is the weakest link in a turbo 400 and there ain't much about a turbo 400 that is weak!!!

[crownedclown]

thanks jeepinpete, for the advice on the part tim e /fulltime issue. when u say "their life iffie" which part r u talking about?

thanks derf, thats very useful , as it validates what ive heard elsewhere today. im pretty sold on the the 727 though. the efi system comes with a billet distributer, not sure if i want to stray to far from the "kit"

wow, i really appreciate all the help, i was beginnong to feel a bit overwhelmed with it all, espeicially considering im doing a full remodel of my house at the same time. Us pollacks arent exactly known for making to much sense.



thanks, and keep them comin


wayne adamski


thanks rogue, i really liked the idea of the forged opinions,lol I mean forged pistons, although i was hopin to stand clear of that expense, but i might just have to jump on in.

[mark j]

Forged pistons are over rated for most builds. Sure if you are going to run nitrous you'll need them. Cast pistons will do fine for your application. Your HP will be limited by the Edelbrock EFI- 400 HP is a very realistic target. Forged pistons expand more than cast and need more cylinder wall clearance. What you get is piston slap until they warm up and conform better to the cylinder. This creates a noticeable racket until they do. Cast pistons won't do this. Be sure to make sure your crank, rods, and block are magnafluxed to look for any hairline cracks before going ahead with the rebuild. I currently have a 401 in the machine shop now- they found 4 hairline cracks between the head bolts and water jackets- all four on the same side of the block. Rather than run any risks I am looking at getting another block. For longevity- balance the rotating assembly and do the lifter valley oil bypass. Bulltear has excellent information on this. Good luck with your build. Look forward to hearing how the Edelbrock MPFI works out for you.

[etjeep]

this is what i have- 76 chief currentlly stock 360

i have already purchased-

401 currently torn down
edelbrock pro flo fuel injection
bjs 6" lift
35s
rancho 9000 shocks
dual rancho steering stabalizer
sway disconnects
heavy dutyu-joint steering shaft
sway bushings

what i need is imfo/ list/advice of items to compliment, my intentions r t o have an extremely capable off roader and daily driver. at this point i plan on using 4.10s, pro/cons/suggestions? i also intend on switching to part time 4 wheel drive, what all do i need to do and buy to make this happen? I plan on rebuilding the 401 using the stock crank, pistons, conneccting rods, and heads. What else if any, would be worth re-using, from the stock set-up? in addition i would like some advice on a quality rebuild kit that would compliment my set-up , and where to purchase. r there certain items i should upgrade upon with a particular kit?

ive contacted edelbrock and they suggested aedel. #2132 cam or a comp cams xe256h. hows that sound?

ignition? Headers? air filter? etc. etc.

should i upgrade timing chain to a double roller or gear drive?

how about the timing chain cover (nickel?) ive read about other upgrades as well, true? needed?

water pump?

im sure ive left out tons of stuff , and appreciate any and all suggestions

thankyou
wayne

I just did the Edelbrock MPFI upgrade with a stock cam. Improvements can be had with an aftermarket cam, but I don't know which one to advise.

4.10s will be good. They will keep you in the power band with 35s at 65-70mph. Consider adding lockers.

Stay away from headers. From what I have heard from people who have them, they are nothing but trouble. Stock exhasut manifolds are fine.

Milemarker makes a PT kit for the QT.

Otherwise you are on the right track.

[etjeep]

I'd reconcider changing your Quadratrac to part time. The 401 is going to put out some decent power. That combined with 35's on the stock D44 makes their life iffy at best. With a full time setup, the power the axle is seeing is only half of what it would be in a part time setup. The QT is great for traction, and you are going to need all you can get!

Right, if you go PT, get ready for axle wrap.

[Rogue]

all I got to say is I own/owned 4 401 engines and know of a few others that ALL had cracked CAST pistons :thumbsup:

[fulsizjeep]

Hey Jeff, I am trying not to mess up my kharma here by saying I have never seen a bad stock 401 piston. I am sure it happens though, no doubt. I made a 258 split open in the front of the block though but that is another story... ;)

Some naysayers will tell you 35s on D44s is asking for trouble. Maybe so if you are a member of the WFO club and only have two speeds: stop and WOT. ;) I have seen a few 4x4s out this way with 4.10s and 35s on D44s and think they are a nice match for street and off road use.

The Quadratrac. If you check/change QT fluid regularly, don't hammer the heck out of it and treat it to a new chain when it gets sloppy, you will see it last a long time. If you drive on snowy roads in the winter, I would advise against a part time conversion. The stock QT is the bomb on snow pack. :thumbsup:

I would also go with a Junk Yard Genious TFI for ignition... NOT, inside joke. :whistle: Heck, throw a new points dizzy in there with a $70 Pertronix breakerless kit and a hot coil. That'll spark it good. Definitely plan to dump the Prestolite ignition at some point.

Headers, schmeaders, if you want them, get 'em. :rolleyes2: Spend good money on gaskets if you do. It is also true that stock AMC exhaust mainifolds are well tuned in their own right.

[Rogue]

no worries on the kharma club... the stock cast piston in my 74 cherokee did last 20 years from the factory, however, it is the weak point of the engine and well.... I've already shared my personal experience with that.

:drivin:

PS - no doubt on the axles... I once thought it kinda weird that drag racers can use a tiny little wimpy 9" ford ( smaller than a AMC 20 in some respects ;) ) behind 1200 horsepower with 29" slicks and not have breakage problems.... but throw some 35's behind a stock engine and all of a sudden you got problems LOL - perspective is everything.

[troopermc]

as for igntion, Ive been running Davis Unified Ignitions D.U.I. distro and wires in my AMC v-8s and I love them....

[shimniok]

The Summit 2132 is a pretty small cam. It's smaller than a factory stock 401 cam by quite a bit. You'd be choking off the engine if you put it in. It's really only a good fit in the 304.

The 256 is also a little small for a 401, especially with fuel injection. It works better in a 360.

The 401 can take a lot more cam than many people think (even around here). I would recommend you don't go any smaller than a Summit 8600 at least. I'm running a Summit 8601 with my TBI setup and it makes pretty good power from idle to redline.

I'm still trying to understand all this better. I have messed with Desktop Dyno but want to discuss this more and learn.

Generally it looks like the bigger the cid, the more cam you can put in. Or maybe with AMC that is because of the high flowing heads. But the advice I have read lately suggests that one big mistake of engine builders is to put too much cam into an engine.

I take that to mean that just cuz the 401 will take a bigger cam doesn't mean you should. It depends on your vehicle and normal operation doesn't it??

My operating RPM due to gearing is 2800 @ cruise on hwy (at 75) ... in the city everything happens below 2000 rpm and I feel I am light on power on that end of the spectrum (less so, now that I have replaced the rebuilt motor with CC260H and Qjet with a stock 360 and 2v)

The gearing (3.73:1 and 33" tires) is too high for it to make sense for me to be running up to 5000 rpm. If I had an OD trans or 5-speed MT, and 4:10s or 4:56's it'd be a different matter.

But given a 3spd and high gears and a 5000# rig with this gearing, doesn't it make sense that I'd want all my power in the idle to 4000 rpm range? With peak torque at cruise rpm around 3000? And ideally, a flat torque curve from idle to peak?

Several of the cams I've modeled (Edelbrock, the 256ish duration single or dual pattern, and a vintage Pontiac grind) do exactly that. They are shorter duration cams with less valve overlap. Without CR mods, they produce on the order of 400 lb-ft @ 3000 and 280 hp @ 4500.

The advice I've read lately echos that a heavy car with high gearing wants just that kind of cam.

I guess it is all about tradeoffs. Some of the hotter cams I modeled put out 375 lb-ft at 2000 but 290hp @ 4500 (and probably peak at 5000). The shorter duration cams gain 15-25 lb-ft at 2000 but peak hp at 4000 to the tune of 260-270hp. So how big a difference is 10-20 lb ft... or 10-20 hp?

Michael

[fulsizjeep]

Michael... I think we have a similar case as I also run the CC260H in my 401 and feel it poops out kind of early, running same gears and tires as you. I am not complaining because it does pretty good in slomo. The one difference between ours is I am running SP2P and you have a Performer. That SP2P chokes the torque/rpm band down since it has smaller runners. Krista can run away from me beginning about 55 with her stock 401 and 31s on 3.07 gears. If I would bite the bullet and put one of these QJs on it on mine, I will probably be happy with the low rev off camber kind of driving for now... ;)

[Rogue]

they say it takes 20 hp for it to register on the butt dyno :D

[fulsizjeep]

heh, he said butt... :p

[shimniok]

[LEFT]Michael... I think we have a similar case as I also run the CC260H in my 401 and feel it poops out kind of early, running same gears and tires as you. I am not complaining because it does pretty good in slomo. The one difference between ours is I am running SP2P and you have a Performer.

That could be doing it, I dunno. Or it could be that yours is a 401 and mine was a 360 (but then I don't think I ever had good power especially below 2000). So... too many uncertainties I guess.

I modeled with dual plane manifold to come up with the numbers. For some reason (jetting or carb) when I went from Edelbrock to Qjet I had a crap load more at WOT than before.

I dunno... :confused:

Basically I just want to figure out what cam to stick in this 401 I've got so I have plenty of torque for pulling mountain passes and in town driving.

Michael

[derf]

Michael... I think we have a similar case as I also run the CC260H in my 401 and feel it poops out kind of early, running same gears and tires as you. I am not complaining because it does pretty good in slomo. The one difference between ours is I am running SP2P and you have a Performer. That SP2P chokes the torque/rpm band down since it has smaller runners. Krista can run away from me beginning about 55 with her stock 401 and 31s on 3.07 gears. If I would bite the bullet and put one of these QJs on it on mine, I will probably be happy with the low rev off camber kind of driving for now... ;)


You put an SP2P on a 401? No wonder you're pooping out early. (Heh, I said pooping.)

The SP2P was designed for the 304. It has really small runners to keep the velocity up at low RPMs to give you good low end torque and throttle response. Trouble is, at higher RPMs, it doesn't flow worth a spit. Put it on a 401 and you're just magnifying that problem.

That intake with the right cam should give you some serious off-the-line torque and respectable fuel economy. But that's it.



One general comment I would like to add about cam selection. Most places that sell cams apply the Chevy reasoning to cam selection. They do the research on their best selling model and then try to apply it to every other engine brand out there. Trouble is, AMC engines are very much different from Chevy engines. A cam that works great in a Chevy engine with Chevy heads, Chevy sized valves and a Chevy exhaust manifold flows quite a bit differently than an AMC engine with AMC heads, AMC sized valves and AMC exhaust manifolds.

What would be great is if someone could get a couple of weeks of dyno research in on an AMC engine using all the different cams so we could see how they all compare. Do a run with 401's, 360's and 304's, complete with all the different intake manifolds. Trouble is, that costs a lot of money and no one wants to do it badly enough. So until someone does, the monkeys answering the phones at the cam companies will just read off the Chevy chart to recommend a cam for your engine.

[JeepinPete]

What I was referring to the weak lin is the D44. 400hp should be pretty easy to obtain with the MPFI 401. Running that through a single D44 on 35's is not a good receipt for long axle life. By keeping the QT a full time unit, you are effectively dividing the power in half to the front and rear axles. A D44 with 35's seeing 200 hp (400hp divided between two axles) is going to live a lot longer.

[derf]

What I was referring to the weak lin is the D44. 400hp should be pretty easy to obtain with the MPFI 401. Running that through a single D44 on 35's is not a good receipt for long axle life. By keeping the QT a full time unit, you are effectively dividing the power in half to the front and rear axles. A D44 with 35's seeing 200 hp (400hp divided between two axles) is going to live a lot longer.

I concur. 400 HP plus 35's will take a toll on a D44. You maybe could put alloy shafts in but that's only a band-aid. I'm running a 401 in my CJ (well, I will be once I get it together) and I'm running a Ford 9" with 35 spline alloy shafts to handle the power going to the 37's. I wouldn't consider running anything less than that.

[fulsizjeep]

You put an SP2P on a 401? No wonder you're pooping out early. (Heh, I said pooping.)

The SP2P was designed for the 304. It has really small runners to keep the velocity up at low RPMs to give you good low end torque and throttle response. Trouble is, at higher RPMs, it doesn't flow worth a spit. Put it on a 401 and you're just magnifying that problem.

That intake with the right cam should give you some serious off-the-line torque and respectable fuel economy. But that's it.


Yes, I am pooping... :p I know the SP2P was designed for 304, but it makes great low end torque on a 401 like you say and I have done this with intention. ;) Fahget about good gas mileage though... :rolleyes:

[shimniok]

A cam that works great in a Chevy engine with Chevy heads, Chevy sized valves and a Chevy exhaust manifold flows quite a bit differently than an AMC engine with AMC heads, AMC sized valves and AMC exhaust manifolds.

For what it's worth desktop dyno does seem to show that some of the big name cams are pretty good and others aren't. The differences aren't huge among most but what was really surprising is the results of the *066 Pontiac pattern. Beat everone on torque and still had competitive hp. (How much would it cost to do a custom grind I wonder??)

I'm curious about some of the less well known manufacturers. If I could get the timing cards on 'em I could try comparing those with the biggger name ones. Surely someone tests cams on AMC motors. Crower lists separate PNs for each specific AMC motor in each of their compu-pro lineup (304, 360, 401) and the numbers sure look like they're at least accomodating cid.

Michael

PS: I tested one or more cams from Crower, Crane, Lunati, Isky, Comp Cams, Edelbrock.

[crownedclown]

thanks for clearing that up 4 me pete. it makes perfect sense


crownedclown

[dusty]

114 and 112 lobe seperation will help maintain vacum the edelbropck efi requires above 16" of vacum at idle.

400 hp was pushing it my motor dynod 433 hp / 517 ft/lbs on the engine dyno with a 770 air gap and hei with the fuel injection bolted later in that engines lift it picked up a ton of mid and bottom end power but above 3500 rpm the engine power became flat, edelbrock was not able to diagnose why we couldnt get it to run a the higher rpms They even had it in thier shop and tried tuning on it a couple of times. it was otherwise a good system.

The 256 is aneimic as is the 260 as is the edelbrock in a 401, was much happier when we ran on stock compression the .480 lift 292 dur 222dur@.050 114 lobe sep on stock compression maintained 20" vacume great bottom end for off road. good mid range for lugging down the road, rpms enough into the 4-5k family to allow passing and creative driving. I think there are better choces than that cam, but that was good for a stock combo. the Comp EX268H worked well offroad and on the street in a 401 combo also.

Cheers

[shimniok]

The 256 is aneimic as is the 260 as is the edelbrock in a 401, was much happier when we ran on stock compression the .480 lift 292 dur 222dur @ .050 114 lobe sep on stock compression maintained 20" vacume great bottom end for off road. good mid range for lugging down the road, rpms enough into the 4-5k family to allow passing and creative driving.

Looks like you have a manual trans, what kind of gearing, tires, etc?

Seems like the 256 and 260 would have loads of torque below 3000 ... did it not have enough above?

Michael

[dusty]

:drivin: :thumbsup: 3.54s with 31's

plenty of torque even with the od cruising rpm is 2k-2200 rpm 4th gear is 3k which works very well when towing, then a down shift to 3rd gear and you are maxed out because hyou are bouncing on 4k. usually when i grab 3rd im straining to pass or to build a little more momentum on a steep hill with a trailer. i like the extra rpm , newer motors all are built with broader operating ranges and definately gain versatility and drivability from the extra rpm range and the benefits that offers.



i have engine dyno print outs that show exactly what i am describing that the 401 will produce the same amount of power (or close to within 10-20 hp or ft/lbs) at 1500-3500 rpm just like the 256 and the 260 but with a much bigger cam and with the bigger cam and right duration you can gain from larger peak torque and hp, as well as a broader operating range. giving you more power when you want it and more rpms when you are glad to have them.


Ran a HMV 272 (one step up from the 260 you have listed) and it worked very well in my old 401. I ran 9.5 forged pistons with '73 model heads and the motor made awsome power- on the order of about 371 hp and about 483 ft/lbs.

It would also rev to about 6,500 rpm. There was a little chop in the idle, but nothing annoying or difficult to tune. I ran this motor with both an automatic tranny and a manual tranny, and it worked well with both set-ups.

the 260 is still a good cam

AMC 401 .030" Over
Bore: 4.195"
Stroke: 3.68"
Compression: 9.6:1
AMC 502 Heads Stock 2.025" 1.68" Valves
670 CFM Carb
Dual Plane performer
Small Tube Headers w/ Mufflers
PAW version of the summit K8601 Cam

RPM HP TQ
2000 156 405
2500 198 416
3000 241 422
3500 295 431
4000 341 453
4500 360 432
5000 351 371
5500 336 330
6000 302 274

_________________

401 .030" Over
Bore: 4.195"
Stroke: 3.68"
AMC 6090 Heads mildly ported 2.025" 1.68" Valves
800 CFM Carb
Dual Plane Intake - airgap
large Tube Headers 1-3/4"tube w/ Mufflers
crower solid 292 cam
CR 10.5:1

RPM HP TQ
2000 161 413
2500 210 432
3000 259 441
3500 314 462
4000 365 469
4500 400 475
5000 429 451
5500 439 412
6000 420 367



same as above but with a single plane torquer intake and a little more tuning/ timing..... couple of factors could have influenced this run that day it was about 10 years ago.

RPM HP TQ
2000 153 387
2500 207 426
3000 260 448
3500 318 473
4000 359 491
4500 421 498
5000 468 496
5500 486 468
6000 472 429

401 w/ stock bore and stock heads, 9.5:1 comp, air gap dual
plane intake, 650 cfm TBI, and small tube headers. comp 260h cam and the Crower 276HDP
>

comp 260h
>
>RPM HP TQ
>2000 169 387
>2500 210 398
>3000 236 412
>3500 271 433
>4000 319 397
>4500 292 354
>5000 271 307
>5500 246 268
>6000 231 202
>

Air gap matched to a holley 770
>Crower 276HDP
>
>RPM HP TQ
>2000 166 427
>2500 210 442
>3000 259 453
>3500 310 465
>4000 339 445
>4500 331 386
>5000 328 344
>5500 311 297
>6000 279 244




WHOA I read the cam specs wrong on this last one very sorry i have corrected it to the best that i can read my scribblings. FYI there is the power print out and then i used to write down the vehicle the motor was going in and the date. then my old build it notebook has the specs in it i copied it onto here wrong

401 9.8:1
R4B 750 Holley
Mildly ported 090 heads
.500/.512
222/226
270/274
112 lobe sep

We should have spent more time tuning on this one but back then time on the dyno was spendy. when tuning on it in the rig it picked up a fair amount more on the top end with some recurving of the dist and larger secondaries In all honesty after a few months if i had taken this motor out and re run it i think it would have come close to 400hp


RPM HP TQ
2000 178 418
2500 214 427
3000 251 449
3500 301 478
4000 346 489
4500 369 443
5000 347 381
5500 316 338
6000 279 284



rarely does my motor see over 5k but having it pull hard right up into 4500-4800 rpm range when passing is right on the money. the 401 because of its large bore and stroke is a very versitile motor and is often under built.

pick and choose carefully. remember my ability to tune or inability to tune on the engine dyno impacted these numbers also the solid cam numbers are from a friends motor

Food for thought