10 reasons why I'm swapping to a SBC

[243]

1. Brand new Goodwrench 350 longblock 5yr 50K warranty...1200.00
2. Selling my used 401 will pay for half the longblock.
3. Dozens of header choices.
4. Single serpentine belt system.
5. Bolts to TH400 without adapters.
6. More R&D than AMC.
7. GM ECM designed for SBC.
8. Better parts availability.
9. Better selection of performance parts.
10. TH400 and steering column is GM so it can't be sacrilegious :D

[ December 24, 2002, 07:32 AM: Message edited by: 243 ]

[Jeeptruck]

Go for it!!!!!!!!

[gp_frk]

Hahahaha

David David David

What about the 4bt?

[243]

Don't need a 4cyl oilburner when I have a 6cyl :D

[Stuka]

erm...the 350 wont bolt to the TH400 that came in your wag. As the one in your wag uses a BOP patern. Not a SBC patern....

[Rogue]

the jeep 400 has an AMC only bolt pattern not a BOP

[Sundowner]

adapters can be had for under $200.

and you forgot that you have umpteen choices for fuel delivery including at least 4 quality OEM systems and $1400 superchargers.

[243]

Thanks Rogue Star, I was about to say the same thing...Stuka, it will bolt to a GM TH400 case without an expensive adapter.

[sandmanb]

so whats the hardest part about the swap? what about wireing ect?

[Rande]

I wouldn't consider that serpentine belt a plus......

[Stuka]

Ahh ok..so it was only the early TH400's that had the BOP? So like 74+ had a AMC bolt patern?

As for the serpentine belt...I find them to be a PITA up here in the cold. I know of lots of guys who through belts trying to start their truck in the colder. Also, you break that, and you screwed. Run dual Vee belts and you have double redundancy. Or even if you run singles, if one breaks, it wont cause everything else to stop working.

[Rogue]

yea forgot about the early ones but I think ( so therefore I'm prolly wrong ;) LOL ) that they had the "nailhead" pattern

[Stuka]

well...I figured they used BOP because they where bolted to Buick Engines. (BOP = buick, olds, pontiac)

The AMC started to put in 360's, and used the adapter ring or what ever...But dont quote me smile.gif

[Retro93]

They used the nailhead trans. and an adapter ring with both the Buick 350 and AMC 360. As far as I know, the BOP pattern case was never put into a Jeep. smile.gif

[Stuka]

ok smile.gif

but...next question...am I correct in saying a later TH400 from a 74-79 FSJ wont bolt to a SBC without a adapter?

[Retro93]

You are correct. AMC only pattern. You can put the guts from the trans into a Chevy case and you will be good to go. No need for an adapter then. smile.gif

[243]

Tell me about the problems you have with the ss belt in north part of the country.

My first experience was a 95 C10 4.3L with no problems, 89 and 93 Mustang 5.0L's with no problems and a 95 Taurus 3.0L which had the idler wheel disentegrate but the first 135K miles without a problem. Then I had a 99 Dodge with the Cummins...again, no problems.

On the other hand, every small block chevy I ever owned had pulley alignment problems.
I have to admit, the AMC has NOT been a problem with the exception of the dual ac belts. Maybe because I didn't know I could buy them in "matched" pairs.
How many more times can I possibly type problem :D

[Crazy_Jeepman]

I think the serpentine belt is great. I have never had any troubles with them. They give you lots of warning when they are going to break. You would have to be BLIND not to see it wearing. Even all our Semis at work, run serpentine belts. Must be a personal choice thing. I know I like them!! :D :D

[ December 24, 2002, 11:14 AM: Message edited by: Crazy_Jeepman ]

[Retro93]

Hmmmm...no problems with serpentine belts either. I just carry a spare belt [one]. Easy to swap out to boot. ;)

[Rogue]

i like serpentine also - very easy to change - only thing i don't like is if 1 thing locks up you lose everything!!! but this usually happens to the people who say "what's that noise?" - "oh well it still runs so i'll drive it"

[Stuka]

the only engines i have seen problems with are the GM 350's. Because the upper tentioner has no sides on it. They may haves fixed it in later years. But I know of several people with older ones who have probs. Not like huge probs, but now and again when its 20 or so out they go to start it and the belt flys off.

[243]

Let me add one more...

11. HEI ignition.

[Rogue]

don't forget

12. - at least its not a Ford

[Chero77]

Originally posted by Sundowner:
adapters can be had for under $200.

and you forgot that you have umpteen choices for fuel delivery including at least 4 quality OEM systems and $1400 superchargers.Where do you get the adpater for $200 or less?

[Chero77]

Well why don't we make a list of exactly what's needed to do the swap and cost it out.

1. Goodwrench Long block.
2. Motor mounts.
3. New carb
4. Water pump
5. Alternator
6. Bracketry for alternator & power steering pumps.
7. HEI dizzy
8. Smog gear if needed in your state.
9. Intake manifold (included in long block?)
10. exhaust manifolds, probably also need a custom y-pipe.
11. new radiator (old AMC one won't work with Chevy, so far as I know)
12. either adapter to AMC TH400 or a Chevy case TH400 to swap your AMC output shaft into.

This is all I can think of off-hand. Anything else?

Possible complications.

Can one fit the Chevy into the engine bay such that the trans and t-case stay in the same longitudinal position? If the 350 has to positioned either farther forward or back than the AMC V8, one may need to lengthen and shorten the front and rear driveshafts.

What about distributor clearance with the rear mounted HEI?

[ December 24, 2002, 08:43 PM: Message edited by: Chero77 ]

[Stuka]

You can put HEI on a AMC, so thats not a reason ;)

[nxcj]

I say "run what you want"! Our Jeeps have always borrowed their stock parts from the big three anyway. As mentioned above; my '86 has Ford ignition, GM steering (column all the way to the box), Mopar tranny, AMC 360....AND the company was owned by Chrysler in '86!
Bottom line is that there are about a billion more SBC in the world than AMC V8's....it's a very simple motor to swap, work on , etc.

Time yourself swapping a water pump on the two and then compare smile.gif

[Retro93]

Note what my donor vehicle is. I'm going to put a Corvette TPI 350/700R4 coupled to a Dana 300 in my Cherokee. The SBC is smaller, lighter and puts out more power than the AMC. To my way of thinking, it is the perfect setup for a rig that isn't called upon to tow heavy loads and will only be used as a trail rig on occassion. All I need now are the motor mounts and a little time. :D

[ December 25, 2002, 10:57 AM: Message edited by: Retro93 ]

[Cliff]

You mentioned the HEI as #11. The Motorcraft Duraspark is superior in stock form to the HEI, and is very easy to convert to MSD. However, the GM distributor itself is easier to modify on an advance machine (at least the early ones).

Be sure to build that bottom end if you plan to do any serious thrashing. It's weaker than the AMC.

I am seriously interested in your 401. Can you please e-mail me at am401@juno.com?

[Crazy_Jeepman]

Originally posted by Chero77:
Possible complications.

Can one fit the Chevy into the engine bay such that the trans and t-case stay in the same longitudinal position? If the 350 has to positioned either farther forward or back than the AMC V8, one may need to lengthen and shorten the front and rear driveshafts.

What about distributor clearance with the rear mounted HEI?Leave the T-case in its original position. Swap in the Chevy TH400 Case, bolt it to the T-Case set the motor in place and then fab the mounts or buy universal SBC mounts. The HEI clears, no driveshaft issues, Wiring is not that difficult. This swap is as simple as it gets. I also have a Chevy Cased TH400 left over from some projects I had on the go, if anyone needs it. ;)

[64Trvlr]

Originally posted by Cliff:
Be sure to build that bottom end if you plan to do any serious thrashing. It's weaker than the AMC.
Where did you get this idea?
:cool:

[mdill]

Expect to lay out 2X what you think it will cost, going in and you should be
all right. Don't do the swap to save money, you won't. The details will eat
the buget to fast and take lots of time. Silly tings like a new radiator and
then expect to spend the better part of a day in the back of the parts store
find the just right molded hoses.

The SBC has many advantages, the engine is chaep, performance parts
are everywhere .... If the goal is to build a real hot performace engine
(Not real good for off road or pulling a 6000 lb car around on the street)
then the SBC might be cheaper, (high cost of swap -low cost performance
parts). But for normal kicking around drive it to the store take it to the woods
the AMC 360/401 is going to be just fine and there are enough performance
parts around to make the AMC engine come alive without breaking the bank.

The differance in price between like a AMC performer package and a SBC
package is what maybe $200, that does not go a long way toward the swap.

I agree run what you want, make the swap if you think it makes sence, let
us all know if you run out of $ before you are done, and need to part it out
we are all looking for deals on parts.

Mike D.

[ColeTrickle]

I have to agree with mdill. But on the other hand it's your Jeep...so best of luck!
One other thing...having to set the timing from behind the engine. I always thought that was the stupidest thing on chevy engines. Don't have any loose clothing doing it :eek: .

[Crazy_Jeepman]

I guess I do not understand why the SBC is getting sold short. I am not a big Chevy Fan, but I do like the SBC over the AMC V8, 360 or 401 for that matter. I just retired a 88 Suburban, with a 350, I towed with it a LOT!!!! Prevous to the Suburban I had a Chevy P/U with the 350 as well, it had my Jeep hauling trailer on it almost continually. I think as far as power and durability, and cost, the SBC would win. 350 has been around for a very long time, and the AMC.........WELL!! I have swapped in a few SBC into Jeeps with very little extra cost.

[Crazy_Jeepman]

Is it true, longer stroke engines generally have more torque?

350 = 4.000" x 3.48

360 = 4.08" x 3.44

Either way its 10 Cubes, not much magic comes from that

[Stuka]

Yes longer stroke makes more torque, but also has a lower redline. Like my ford 289 has a 2.87" stroke, it will rev forever, it likes higher rpm's. But take the 360/401, they have larger strokes, and generate WAY more low end then a 289 or the like.

The SBC is a good engine, not going to say it isnt. But I feel the torque of the 360/401 is more suited to a offroad vehicle. I have lugge my 360 down too 400rpm going up some hills, and if i hit the gas, it pulls out of it with no problems. People I know with 350's cannot do that, they will stall out.

EDIT: Also the heavier internals of the 360/401 help give it more torque. Lighter internals (forged aluminum rods, aluminum pistons and the like) make for less torque, as those are designed to let the engine rev higher.

[ December 25, 2002, 11:05 AM: Message edited by: Stuka ]

[Retro93]

TPI = all low to mid range torque. Due to the runner design of the system, most of the power is made down low where it is needed. :D

[Chero77]

Another consideration is that one day these vehicles may become collectable, and if so, an FSJ with a conversion engine will be worth little, while the same vehicle with its original 401 will command a substantially higher price. In the collector car world conversion engines destroy a cars value.

[mdill]

The chevy is a good engine, and if you are dead set on going to a port injection
setup or more on the perforamnce side (Alloy heads/block) or a overdrive trans
as part of the package then I think the cost ratio would side with the SBC.
But swaping a mild to lo-performance chev in place of a mild lo-performance
AMC does not make the cost/benift cut in my opinion.

We all have our personal preferances on makes/engines but when it really comes
down to it for low RPM use pretty much all of the old iron V8's from any of the
big three (and AMC) will have aceptable performance in similar trim (CAM, induction ..)
Each of them have their quirks and each have their good points. The chevy just has
market share going for it, that what makes it stand out more than anything else.

Mike D.

[The PIG Smith]

I have been told, and I believe it, that AMC engines develop more torque at lower rpm than another V8 built.

Correct me if I am wrong.

[Crazy_Jeepman]

That would be wrong. Then again I am not sure what you are comapring it to. However the AMC 360 will provide 15 LBS more torque than the 350 Dauntless. However the 350 Dauntless will do it at 200 RPMS less, making it the bottom end engine over the AMC 360. Still does not matter we are talking minimal diferances across the board when you are comparing the 360 to Small Blocks. There is just not enough Cubes, Stroke differance, or any other differances to set apart from anyone engine.

[krob725]

243
i think it is a great idea. i would like to see you go with the 4bt, but the sbc is good also. i have been a dodge guy for years, but i installed an LT1 in my bro-in-law's 89 GW a few years ago. it turned out real good. we went with a 700r4 and he says he was getting over 20 MPG. if you go with the SBC try to get an FI setup. it costs more but it will be well worth it.
krob725

[243]

The AMC 360 and 401 are essentially the same as a 350 Chevy as far as I'm concerned with an edge going to the 401 for the additional displacement. To say otherwise is really "splitting hairs". I'm not going to build a high rpm, high horsepower motor and I'm not looking for stump puller...but something in between with 250-275 hp and 300-325 ft-lbs of tq.

I have much more experience with the SBC than the AMC which IS an advantage. Although I do expect to spend more money in the long run I don't think it will be 2X a rebuild of the 401.

Yes, my Cherokee is a classic but I have no desire keeping it stock with a 360 2V, factory seats, door panels, tires and wheels; so, would it really matter if it had a different motor? probably not smile.gif

I priced all of the machine work needed to thoroughly rebuild the 401 plus a Summit rebuild kit less the crank and rods and it was hundreds more than the Goodwrench motor. Plus, I don't have to deal with a machine shop or assemble the motor. Lets not forget the 3yr 50K mile warranty that applies even with upgrades as long as they are not internal.

Here is a link to a long but interesting buildup of the Goodwrench 350 by Chevy High Performance. I was looking for internet pricing on the motor after I started the thread.

http://www.aros.net/~rbuck/chp/

krob, I would really like to do the 4BT but it will entail more fabrication than the SBC and I am not convinced I would be happy with an rpm shifted TH400 compared to a vacuum modulated tranny. I may try to drive a tater chip truck to get a better idea but the little Cummins is falling to the back of my list.

Chevy 350, TH400...maybe I should finish it off with an NP205. My project is starting to sound like a mid-70's K10 with a Jeep body. Those were pretty good 4X4's too, wouldn't ya'll agree :D

[Stuka]

I can see the amc 360/401 putting out more low end torque then any other small block, but not any V8 period,, as a ford 460 has 430ft pounds stock in most years, and swapping in a RV cam will get it up close to 500ft pounds with no other mods.

[mdill]

243,

The mid 70's K10 had pretty good drivetrains but why would you want to stay
with mid 70's tech, if you are going for it get atleast the GM 300hp + (the one with
the iron vortech heads) for ~$2K you will have a pretty stout lower end and
pretty nice heads, then back it with a 700r4 (I know they have a bad rap with some
but current up grades they are OK). take your pick of transfercases depending on the
need (In texas I don't think full time 4X4 is a high on the list like it is up here in the
land of 6 months of ice).

BTW, the mid 70's 4x4's only came with the TH350 and only with the small block.

Mike D.

[BostonWagoneer]

My snow blower could use a new engine right about now. I think that for $1200, a nwew Goodwrench 350 would be just the ticket. How hard would it be to bolt that to a 1978 Craftsman blower? Does it bolt to the stock 4-speed tranny without an adapter?

AMC = All Makes Combined

[Stuka]

boston: no that requires a adapter ring, and you need to fab some motor mounts. Also your range will be greatly reduced, so a larger fuel tank would be advised. With the added power tho you can go up to larger tires without having to regear though smile.gif

[Retro93]

Good one Brandon. Now where would one find the obscure Chevy/Craftsman adapter? ;)

[ December 26, 2002, 01:36 AM: Message edited by: Retro93 ]

[64Trvlr]

Originally posted by Stuka:
I can see the amc 360/401 putting out more low end torque then any other small block, but not any V8 period,, as a ford 460 has 430ft pounds stock in most yearsHow long has the Ford 460 been a small block?
:cool:

[Stuka]

you misunderstood what I said. I said I can see the AMC 360/401 putting out more torque then any other small block, but not any V8 period. I said the 460 had more...as its a big block. Above my post somebody else said they heard the AMC had more torque then any other. So I said sure maybe then any other small block...but not any V8 period. Nowhere did I say a 460 was a small block.

[ December 26, 2002, 01:43 PM: Message edited by: Stuka ]

[Chero77]

I think what it really comes down to is with the basic Goodwrench 350 you know what you are getting, a reliable NEW engine, backed by a good warranty, all for about $1400 (the going price in my area). If you go the rebuild route, you really have no clue whether you are going to get a decent engine or a $1400 worth of junk. Also, while I can get a 401 rebuilt in LA for $1400 at several places, none of them will include new valves or valve springs or balancing for that price. All that stuff costs extra.

So I guess one question I have is how many feel that new valves are mandatory in a rebuild?

It seems like leaving 25 year old valves in your engine is asking for trouble. One broken valve head equals one scrapped motor. Keeping the old springs seems like a more acceptable risk as they can be replaced without tearing down the engine and if they break they don't destroy the motor.

243, can you post your estimate of the total costs of the Chevy 350 swap? Since this question comes up time and again, maybe we should produce a complete cost breakdown and post in the technical articles section.

For me the question is really whether to rebuild (seems risky), swap (sounds expensive), or simply sell the vehicle (sounds practical).

[ December 26, 2002, 02:20 PM: Message edited by: Chero77 ]

[Stuka]

I would never reuse valve springs, as they get soft over time. They are easy to put in, not rocket science. You can reuse valves, I know of several who have, although personally I would replace them.

[Chero77]

Originally posted by Stuka:
I would never reuse valve springs, as they get soft over time. They are easy to put in, not rocket science. You can reuse valves, I know of several who have, although personally I would replace them.I think the valves should be replaced too. There is at least one person on this board who scapped a motor because a valve dropped into the cylinder and at least two guys on the AMC board have had this happen as well. Used valves seem unduly risky to me. Then again, I can see why shops don't replace them. New AMC valves are about $12/each which new Chevy valves are about $4/each.

[243]

C77~

I can post an estimate and I think it would be a nice addition to the technical forum...as alway's, YMMV.

I didn't even get to the heads with the machine shop. For starters, I would not use the original valves after a full rebuild of the shortblock. So add valves, springs, keepers, shims, rocker arms, bridges and bolts, 3-angle valve job, gasket port match (by owner), hot tank and magnaflux. Sounds expensive, WAG would be 200.00 a head...sound reasonable?

That would make the 401 approximately 2000.00 for the long block. Add 250.00 for a timing chain cover for a total of 2250.00.

The Goodwrench motor needs an intake and distributor 250.00 and single serpentine belt system WAG 100.00. So, 1750.00 +/-. Then I need to find a 4-core radiator with the correct inlet and outlet which could be 250.00-300.00.
Both motors would get new accessories so I would call it a wash in that respect.

It appears that the basic motor will cost approximately the same but I've done this long enough to know there are items I've overlooked and incidentals that go along with every "project".