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Old 01-04-2008, 08:05 AM
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Greg Taylor Greg Taylor is offline
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Question 360/304 V8 Head Swap Questions - Hi comp / low comp, etc!

Hi all,
I am doing some work on my 1989 Grand Wagoneer engine and am considering swapping heads while I am at it. I need some feedback from the experts, please!

My Jeep has a stock remanned 360, which is probably 0.020 or 0.030 overbore. Reman company is unknown, but it has about 60,000 miles on the reman (11 years old … done in 1997, 3 owners ago). I'm pulling the front timing cover to fix a coolant leak behind the fuel pump. I'll be installing a new Bull Tear front cover and nickel plated pump cover, double roller timing set, Bull tear matching cam/distributor gears, GM HEI, & a hi-flow water pump for this ‘initial’ build up. I’ll also be swapping from a 600-cfm 4160 to a 670-cfm 4150 Street Avenger.

I have been considering pulling the intake and heads while I'm at it and installing some 'built' heads I have. I have the 1979 304 (59 cc) heads I was building up for a 304 stroker turbo motor I was going to use in an AMC race car. I have ported and polished these heads (about 40 hours into them) and they are currently machined for CHEVY Milodon Megaflow 1.94 Int & 1.50 Exh. valves (they're smaller than stock 360, but have smaller stems and undercut stem in the runners). I am considering having them machined for larger Chevy valves, as Milodon makes much larger Megaflow valves.

How much larger can I go on a 360, with intake and exhaust valve size?

These 1979 304 heads also have the combustion chambers opened up as detailed in Performance American style, so they are probably about 62 cc's in size now. How much would this drop the stock 360's 8.4:1 compression? If it would drop too much, how much can I mill off the AMC heads, to bring compression back up? IF I could machine 0.100" off the heads, there are 0.100" longer Chevy valves that would make up the difference in valve height so that "theoretically" the pushrod length would not be affected.

My 1979 304 heads have been machined for 3/8" studs for the Harland Sharp roller rockers I plan to install.

How much would compression be raised if the 52 CC 70-71 304 heads were installed? Just curious. Stock 360 is 58 CC through 1984, from what I can find.

Last night I spoke with long time AMC club member (here in MI), Rick Jones, who built the 401 for my ’78 Cherokee Chief. He was telling me that he recalls that the later heads (like on my 1989 GW) were around 65 cc’s. Can anyone confirm this or have casting numbers available (my heads are still on the engine)? From the information I found online, the 360’s were 8.4:1 compression 1971(late)-1984 (58 cc heads). However, my 1989 GW has 8.25:1 compression. If this is due to the 65 cc heads (and probably piston combo), then I might be OK in swapping the ported/polished 62-cc 1979 304 heads I have modified. This would raise the 8.25:1 compression a bit (3 cc smaller heads). What do you all think? I would also be able to swap the 1970 304 52-cc heads as well, and raise compression up a lot (13 cc smaller heads).

Rick also told me that he has these 1970 304 heads on a 304 he built for torque and gas mileage. The engine turned out to be a real screamer with a small carter carb and the same intake I am running (see below). He’s getting 22+ MPG in his Javelin with it mated to an AX4 Jeep 2WD tranny.

As a side note, I am running the Holley Street Dominator intake. It’s a single plane intake with equal length runners. The intake runners are full size and then taper down to a smaller square port where they mate up to the head ports. It works well on the Jeep for added torque. I also had it on my 401 Rick built for me.

Lastly, this motor isn’t geared towards turning huge RPM’s. It’s a driver and occasional recreational off road FSJ here in MI (nothing crazy). I am simply wanting to get more power out of it and am building it to get better mileage, supplementing the gasoline with hydrogen-on-demand and water injection.

Thanks for the feedback, all.
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Rochester Hills, MI

1989 Grand Wagoneer "Terminator 2"
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Old 01-04-2008, 10:31 AM
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BarryL BarryL is offline
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I can't comment on standard CR or chamber sizes, but one thing I picked up on is where you mentioned taking .1 off the head surface and going to a longer valve stem to make up the pushrod length difference. It has been awhile since I've done serious head work and set-up, but valve train geometry is critical for performance and wear. The rocker arms and valve geometry is a critical alignment. Pushrods are typically sized lengthwise to yield the correct geometry, not the other way aroud.
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Old 01-04-2008, 10:53 AM
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Take .023" off the head you will gain .5 in compression.
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  #4  
Old 01-04-2008, 11:59 AM
ne715 ne715 is offline
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[quote=Greg Taylor]Hi all,


Last night I spoke with long time AMC club member (here in MI), Rick Jones, who built the 401 for my ’78 Cherokee Chief. He was telling me that he recalls that the later heads (like on my 1989 GW) were around 65 cc’s. Can anyone confirm this or have casting numbers available (my heads are still on the engine)? From the information I found online, the 360’s were 8.4:1 compression 1971(late)-1984 (58 cc heads). However, my 1989 GW has 8.25:1 compression. If this is due to the 65 cc heads (and probably piston combo), then I might be OK in swapping the ported/polished 62-cc 1979 304 heads I have modified. This would raise the 8.25:1 compression a bit (3 cc smaller heads). What do you all think? I would also be able to swap the 1970 304 52-cc heads as well, and raise compression up a lot (13 cc smaller heads).

Rick also told me that he has these 1970 304 heads on a 304 he built for torque and gas mileage. The engine turned out to be a real screamer with a small carter carb and the same intake I am running (see below). He’s getting 22+ MPG in his Javelin with it mated to an AX4 Jeep 2WD tranny.

As a side note, I am running the Holley Street Dominator intake. It’s a single plane intake with equal length runners. The intake runners are full size and then taper down to a smaller square port where they mate up to the head ports. It works well on the Jeep for added torque. I also had it on my 401 Rick built for me.

quote]

Is this the same Rick Jones with the Rambler Scrambler? He works for the same company I do and in fact I owe him some parts that he has been waiting for since before Christmas. Tell him I said hi.

My question...doesn't the 304 heads have smaller intake valves? I would think that smaller valves would lessen the amount of fuel air mixture that could get into the engine for combustion. IIRC the heads that are smaller combustion chamber have the "319" or "913" castings. I can never remember the correct number. It seems like from your information that AMC made quite a few different "cc'd" chambered heads, I didn't think they did but then I'm no expert.
Pick Rick's brain, he's very knowledgable about anything AMC.
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Old 01-04-2008, 12:13 PM
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Did you cut all the meat out of the runners on the 304 head? I know they have a serious neck down just about the valves.
I would think that would be the biggest issue for using them.
On a 360 engine, valves around 2.08 intake and 1.74 exhaust I think are about the biggest without running into other issues.
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  #6  
Old 01-04-2008, 12:24 PM
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Greg Taylor Greg Taylor is offline
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Quote:
Originally Posted by ne715
Is this the same Rick Jones with the Rambler Scrambler? He works for the same company I do and in fact I owe him some parts that he has been waiting for since before Christmas. Tell him I said hi.


Howdy!

Yes, it's the same Rick Jones ... and ... I did pick his brain last night. He was thinking that I should try the ported/polished heads I have currently in the process of build-up, even if they lower compression a bit … based off the thinking that all 72+ 360 heads have 58 cc chambers, however 58 cc is through 1984 (from digging) ... mine might be larger 65cc, since they're '89 vintage castings for 8.25:1 compression)


Rick was also saying that the 1970/71 small chamber (52 cc) 304 heads run great on his 304. He was thinking that the smaller valves would generate more torque on the 360.


Here is the valve size comparison:


STOCK 304: (3/8" stem)
1.787 intake (22% Smaller than stock 360)
1.406 exhaust (30% Smaller than stock 360)



STOCK 360: (3/8" stem)
2.025 intake
1.68 exhaust

PORTED 304 w/CHEVY VALVES: (11/32" stem, undercut to 5/16" in runners)
1.94 intake (6% Smaller than stock 360)
1.50 exhaust (20% smaller than stock 360)

*** NOTE: These are Milodon Mega Flow valves with smaller undercut stems which greatly increase low-mid RPM air flow. I installed these into a 258 cylinder head (stock valve sizes are same as 304) and picked up an easy 30 HP. Power diference was night-n-day before and after. Even though the total valve area is less than stock 360, they have new angled valve job, which flows better and much better low-mid flow than stock 360 and ported runners for more flow.

What’s your name so I can pass the HI along to Rick?! Thanks.
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1989 Grand Wagoneer "Terminator 2"
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Old 01-09-2008, 08:31 AM
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Greg Taylor Greg Taylor is offline
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Thumbs up

Good morning everyone,
I have received feedback from both sides on this question, some say Yes and others No (that the smaller exhaust would limit the heads). Last night, I finally received REAL WORLD feedback from long time AMCer Ron Waters in Georgia. Here is his email in detail … looks like 304 head with Chevy valves are a GO!

P.S. Ron’s website is www.classicone.com/wsc



From: "Ron Waters" <ron@classicone.com>
To: amundaza@yahoo.com
Subject: AMC 360 Heads
Date: Wed, 9 Jan 2008 01:25:53 -0500

Greg..

Have done alot of work on street performance 360's and have found that by using the 304 heads and installing chevy 1.94" intake and 1.6" exhaust valves (ps: Chevy stainless valves are real cheap too) and blending the bowl area for the bigger valves, that bottom and midrange hp and torque go way up compared to the 360/401 valve sizes which really hurt the 360 in the bottom and midrange with compressions ratios for today's pump gas. (8.5 - 9.5 +/- compression). The engines if set up with the right cam, intake, carb, etc will still pull to 5500-6000 rpm. We also make sure the valves are un-shrouded (fly cut the chamber walls around the valves) and usually open the chambers up to about 62cc's. Even if you do nothing to bring the compression back up with the larger chambers, the breathing efficiency gain is more than what is lost with a little less compression. Cutting a little of the stock head surfaces after opening the chambers up will help a little as will decking the block as much as feasible.

Ron Waters
WSC Motorsports
770-413-9126
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Greg Taylor
Rochester Hills, MI

1989 Grand Wagoneer "Terminator 2"
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Old 01-14-2008, 01:57 PM
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Greg Taylor Greg Taylor is offline
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Question More Build-up questions

Quote:
Originally Posted by jeepsr4ever
Take .023" off the head you will gain .5 in compression.

I am in the process of pulling the 360 and planning to install the 304 stroker motor I was originally building for my race car (from years back). Can I get your feedback on it, regarding the build-up:

Here are the engine details are listed below.

BLOCK: 1979 304 V8 - 2 bolt mains with a 4140 Chromemoly main girdle system. O-ringed deck surface (milled 0.010" off of deck)
HEADS: 1979 304 V8 - ported/polished and enlarged combustion chambers (porting/polishing via Perf. American Style specs). Set up for SB Chevy 1.94 intake/1.50 exhaust valves (Milodon Megaflow SS with undercut stems)
CRANK: NOS 390 crank - cross drilled & auto adapter machined into place
RODS: '68-69 390 rods - resized, shotpeened, deburred and polished, full floating piston pins, ARP bolts
PISTONS: Venolia forged aluminum with tool steel wrist pins (390 size 1.0")
CAM: Crower Turbo Master Cam (cam I was going to use originally)
LIFTERS: Rhodes anti pump-up hydraulic lifters
ROCKERS: 1.6:1 Roller rockers
OILING: External valley oil supply line for rear mains & Rear oil galley external tie line
BOLTS: Milodon Main & Head studs

This engine is about 80% ready for assembly. The internals have all been weight matched and balanced (internally). It could easily turn 6500+ RPM as it has been built to be a race engine.

As a turbo motor, it was purpose-built to have 7.88:1 compression ratio (with ROL 0.045" head gaskets) with the ported 304 heads (~62 cc)... same heads we have been discussing for use on the 360. If I run a thinner head gasket (0.021") I can bring compression up to 8.29:1 using the existing ported 62cc heads. If I milled these 62cc heads 0.023" (per Bulltear) I could raise compression 0.5 ... up to 8.38:1 (0.045" gasket) or 8.79:1 (0.021" gasket).

I could alternately do a mild port/polish to the 52cc 1970 304 heads (I just picked up) and modify them for Chevy 1.94/1.50 valves. These 52cc heads would bring compression up to 8.67:1 (0.045" gasket) or 9.2:1 (0.021" gasket). IF I milled these heads (0.023" again, per Bulltear), I could run 9.17:1 (0.045" gasket) or 9.68:1 (0.021" gasket).

What do you think about this engine combination and the various compression ratio options. I would 'prefer' to use the 62cc heads I currently have modified for Chevy valves, but that limits compression to around 8.3-8.8:1, depending if I have them milled or not. How much would milling affect valve geometry and pushrod length? I believe that the roller rockers for these heads, have the adjustable studs, so could they make up the pushrod difference (from stock length)?

I am wondering if the cam Nick Alfano suggested for the 360 would be a good candidate for this stroker motor. It is similar to the Crane Fireball cam. Actual displacement on this engine is 321 CID. With the long stroke and smaller bore, it would be a good torque motor for the Jeep, in addition to the Chevy valves, sized for the 304, allowing really good breathing for torque and power on this engine. When I engineered it, I planned to run it under GOBS of boost, up to 6500 RPM.

Also, since the block is decked 0.010", would I need to mill the intake manifold at all? What about if I mill the heads, would I simply need to open up the intake manifold bolt holes, to align with the heads?

So .... what are you thoughts on this?? Thanks!
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Rochester Hills, MI

1989 Grand Wagoneer "Terminator 2"
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Old 01-14-2008, 02:25 PM
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j20brett j20brett is offline
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If you are going to be tearing it down that far and adding a new intake/ crab, why not add a new camshaft as well? Pretty cheap and easy with it torn down as far as you will have it.
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Old 01-14-2008, 06:32 PM
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Greg Taylor Greg Taylor is offline
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Quote:
Originally Posted by j20brett
If you are going to be tearing it down that far and adding a new intake/ crab, why not add a new camshaft as well?

Hey Brett,
I was planning to add a new Clamshaft with the 'crab' , but then decided to yank the motor and install the stroker 304 I began the build up on about 12 years ago. The 360 in my Jeep has about 60,000 on a stock rebuild. The stroker 304 (321 cid) should prove to be a torque motor and I would estimate it to be making around 300 HP when done. It is a race engine, balanced and blueprinted, with forged internals.
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Old 01-14-2008, 07:55 PM
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very nice
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