AMC V8 Stroker Combinations (using 304 and 360 blocks)

[amundaza]

Hey guys,

I ran a couple of storker combinations through the calculator and came up with some interesting combinations to build.



342” STROKER (304 block & 390 crank)

Offset grind the 390 crank for a 2.10” Chevy rod journal, which allows a 3.782” stroke

Run off the shelf Chevy 5.7” H-beam rod (I Noticed that SBC rods are narrower than 390’s, so a Chevy H-beam 6-cylinder rod could be used, it’s slightly wider than 390 rod width and has a 2.0” journal).

Off the shelf 0.060” over (stock is 3.736”) Keith Black 305 Chevy piston (1.56” pin height & 5.5 CC valve reliefs).

With my current deck height (.010” milled), I get a .002” deck clearance (would be 0.012” on stock 70+ block).

With my current 62cc 304 heads (ported and polished … SBC valves), it comes to 9.94:1 compression.

It can also run their 16 cc dished 305 piston, to get 9.6:1 compression.





435” STROKER (360 block & 390 crank)

Offset grind the 390 crank for a 2.00” Chevy Rod Journal, to a 4.07” stroke.

Run off the shelf KB Chevy 400 pistons at STD bore 4.125” (1.433” pin height & 22 cc D-dish).

Run off the shelf 5.7” H-beam rods for Chevy 6-cylinder (wide big end rod)

Comes out to 9.75:1 compression and 0.030” deck clearance.

It can run an 18cc D-dish piston to achieve 10.1:1 compression



So, what do you think about these combinations?


Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[tufcj]

The only problem I see is that off the shelf Chevy pistons have the valve reliefs in the wrong place for AMC heads. It might be less pronounced with the 304 heads with 1.94 and 1.50 valves, but running stock 360/401 heads with the 2.02 and 1.65 valves, you'd have to re-cut the reliefs.

You'd probably want the big valves anyway, AMC engines like and need to breathe.

Bob
tufcj

[Wrench Man]

I still don't understand every ones obsession with stroking the AMC's?????
they would make lots of torque but you cant wind them very tight!
The 343 I have SCREAMS!!! and if it had some good heads on it, it would probably make really good power!? it's rated at 280hp and 365ftlbs stock!?

I suppose those combos would make great trail/towing motors for jeeps!

[amundaza]

I still don't understand every ones obsession with stroking the AMC's?????

I already have a 304 stroker started from years ago, for turbocharging in a race car application. Since my project changed directions and I sold the car years ago, I still have the motor to complete and use in SOMETHING! I engineered it back then with a 390 crank in a 0.030" over 304 block and to 7.8:1 compression for high-boost turboing, which I don't want to run on a street/trail driven Jeep.

I may just opt for getting different pistons made up to raise the compression back up, since an 7.8:1 304 'race engine' would be anemic in power. I currently have a forged Venolia piston for the 304, based off of stock specs, but just a tad bit shorter on C/D.

I'm looking to bring it up to 9.5:1-10:1 and then grooving the quench area of the cylinder heads, to improve the burn characteristics.

I've seen some good input from racers doing this on high compression engines, being able to burn 87 octane pump gas with 10.5:1 motors and getting better power and economy due to the increased burn.

For more on the grooves, check out http://speedtalk.com/forum/viewtopic.php?t=4069 & the guy who started it all : http://somender-singh.com

I've also been in contact with one of the posters on the Speedtalk forums (automotivebreath user ID) and he has a stock 95 suburban he built up to 10:1 compression and uses the grooves with 87 octane gas.

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[amundaza]

Here are more calculations on the 304 Stroker Motor ...

350” STROKER (304 block & 390 crank) … Now this looks like a killer combination to run.

Offset grind the 390 crank for a 2.10” Chevy rod journal, to a 3.87” stroke

Run off the shelf Chevy 6.0” H-beam rod

Off the shelf 0.060” over (stock is 3.736”) Keith Black 305 Chevy piston (1.261” pin height & 5.5 CC valve reliefs)

With my current deck height of 9.198” (.010” milled), I get a .002” deck clearance (would be 0.012” on stock 70+ block)

With my current 62cc 304 heads (ported and polished … SBC valves), it comes to 10.2:1 compression

This combo can also run the KB 12 cc D-shaped dished 305 piston with a 5.7” rod, to get 9.45:1 compression.

Also, I was incorrect on the AMC 390/401 rods being wider than the SBC. I was thinking of the AMC 327 forged rods, which are 1.00” wide and have the same journal size as the 390/401 (327 rods are 6.375” long and are FORGED).

The 390/401 rods are around 0.92” wide, while SBC are 0.94” wide. This really opens up the possibilities with running a variety of SBC rods on the 390/401 crank.


Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[jeepsr4ever]

Your stroke cannot be done unless your willing to weld up the crankshaft. The stock stroke of a AMC 390 is 3.577"-3.571" (from factory tolerances). So that is 1.7855-1.7885 from pin center to main center. For a 2.00" chevy rod journal the max stroke you will get out of a completely perfect crank is .1247 more stroke from rod pin center to main which gives you a .2494 increase in overall stroke or a stroke of 3.8264"-3.8204".


Lets say you go down to a .060 racing bearing for a chevy 2.00" journal. From a perfect crank (rods at 2.2495 diameter) you could get .3094 increase in stroke or a possible stroke of 3.8864"-3.8804"....this would be .060 under rod bearings starting with a perfect factory crankshaft and having a crank cutter that was VERY meticulous. I think realistically your looking at a max stroke of 3.800 with a 390 core crank.

3.800 stroke/bore CID possibilities

4.08=397ci
4.115=404ci
4.125=406ci
4.195=420ci
4.250=431ci

I would not use a 327 AMC set of rods for any stroker build. Your better off even with some chinese 4340 H or I beam rods to start with. Now you could try welding and annealing, stress relieving and nitriding (fwew :D ) to gain your stroke but I think in the end the small cheek wall after the radius on the rod journal sides would dissapear at the top end leaving you with the bottom half holding the rod in place (which may be alright...may not).

Alot of crazy strokes have been done already and their is much to learn and rehash but in the end the best choice for a stroker crank is either new, cryo'd used or a billet crank. Forged cranks are so benficial because they take more flexing than a cast crankshaft but they have a finite fatigue life. Once they reach close to the point of breaking the deep cryogenic process can help the molecules settle and re-align.

I like your thinking though!!! :!:

[amundaza]

Thanks for the feedback. I'm not quite following you math here, please correct if I am wrong.

I have an NOS 390 crank, which I have previously had cross-drilled for my engine. The mains/rods have been left at stock diameters, so I assumed the 390 rod journal at 2.248" and half the 390 crank stroke of 3.574" = 1.787".

2.248" - 2.100" = 0.148" (offset available).

0.148" + 1.787" = 1.935"

1.935" x 2 = 3.87" stroke

This is how I calculated the numbers to get a 3.87" stroke. which theoretically seems possible with a 2.100" SBC Rod. You're discussing however, a 2.000" rod and only being able to achieve a 3.800" stroke with said rod and 390 crank ... this is where I am not following your math.

Once again, please advise on my math, compared to yours and if there is something I am missing here with offset grinding a crank in reality (as opposed to on paper).

I still have to get my block deck height re-checked, as it has 0.010" milled from the deck and O-rings installed (originally for turboing). I theoretically calculated my new deck to be 9.198" (stock 9.208" - 0.010"). Since there is a factory deck height tolerance, I'll have to calculate mine exactly, so that I get the stroke, rod and c/d correct, and near a zero deck on the pistons.

Also, I only mentioned the AMC 327 forged rods, as they are the ones that had the wider big end, which I though the 390/401's had.

Thanks for the added feedback.

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[jeepsr4ever]

What you missing is you can go down to that 2.100 but its the centerline that will only change so your only gaining .148 in total stroke not .148 x 2. :idea:

[amundaza]

What you missing is you can go down to that 2.100 but its the centerline that will only change so your only gaining .148 in total stroke not .148 x 2. :idea:

Hello again!
Yeah, I finally figured that out last night. I drew up (in my head) and overlay of the AMC and SBC journal at centerline and realized that, as you pointed out, I'm only gaining half by offsetting the difference. Looks like the theoretical MAX a 2.100 SBC journal could net is a 3.722" stroke from a stock AMC rod journal.

Thanks again for the help ... now back to the drawing board.

I am also considering having my 390 rods offset bushed 0.060" for a SBC pin, to 5.85" and simply running the 305 piston and the stock 390 stroke.

The other option would be to take a 401 rod and offset it back 0.008" to 5.85" and SBC pin size. Do you know who makes the AMC forged 401 rods (I-beam and h-beam) and if they could be direct ordered with said SBC pin size and rod length? Thanks!

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[Goose]

Wow, That is a lot of brain power right there.. :shock:
:lo1l: :lo1l: :lo1l:
:sa:

[amundaza]

Wow, That is a lot of brain power right there

Gigabytes of space there, just sometimes lacking in processing power, depending on time of day. It's like having a CAD tube right there inside my head! :!:


Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[jeepsr4ever]

Their are those that make the I and H beam rods for a 401 and you can get bushings pressed in and try some stock pistons (with locks of course). I think currently Cat-pep are theonly ones making those rods.

[amundaza]

Good morning all,
Well, I have redone my calculations and come up with a nice 383" stroker, using the stock 390 crank (3.574") in my 360 block, bored for 400 SBC pistons (4.125" ... AMC 0.045" overbore) and a SBC 5.85" rod.

The 390 rod journals would simply need to be turned down and widened a bit for the SBC 2.100 rod, the stroke would be left at 3.574".

This combo with a 12 cc D-shaped dish piston, nets a 0.010" deck clearance and yeilds 10.0:1 compression. This is using my current 304 heads that have been opened up to roughly 62 cc's, mildly ported/polished and bowls opened up for 1.94"/1.50" SBC valves.

I would probably run the current 1.94" intake and open up the exhaust valve to a 1.625" (currently at 1.50").

I would also considering taking my stock 360 heads (1989 360) and opening up the bowls and porting polishing them, then running stainless AMC valves at 2.02/1.68". Either way, I would groove the cylinder heads, for the compression bump, so that 87 octane pump gas can be run.

Should I need to mill the block a bit, I'd open up the combustion chambers beyond 62 cc's to keep compression at 10.0:1.

If the block does not need to be milled, then 401 H-beam rods at 5.858" length could be run. They would get bushed for SBC 0.927" pins ... and the virgin crank would not need to be ground.

This seems like a more feasible stroker to build. What do you all think about this combo? Any ideas on HP/Torque for this? It will reside in my Jeep Grand Wagoneer.

Now to sell of the 304 race block, 390 rods, Fischer balancer, turbo camshaft and Venolia pistons.

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[amundaza]

Good morning all,
Here is the final build-up breakdown for my stroker 304… the reason it has taken me SOOOOOO long to come to a decision (304 vs. 360), is that I really wanted to find a build that would utilize most of my existing turbo v8 parts, converting them to naturally aspirated street-use and not cost a ton more money. This 327 build fits the bill and will make decent power on the street. The big set back with the AMC turbo parts were the Venolia pistons being built for turbo use at 7.78:1 compression with 62cc ported heads.

BLOCK: 1979 304 V8 - 2 bolt mains with 4140 Moly main cap support straps (center 3 mains). O-ringed deck surface milled 0.010”
CRANK: NOS 390 crank - cross drilled & Auto tranny adapter machined into place (Perf. AM Style mod)
RODS: '68-69 390 rods - resized, shotpeened, deburred and polished, full floating piston pins (bushed for Ford Pinto 2300cc pins 0.9122”), ARP bolts
PISTONS: Keith Black Ford 2300cc pistons 1.59 c/d flat top, at 3.82” bore (0.040” over Pinto … 0.070” over AMC 304)
HEADS: 1979 304 V8 - ported/polished and enlarged combustion chambers (~62 cc) (porting/polishing via Perf. American Style specs)
VALVES: Small Block Chevy 1.94 intake/1.50 exhaust : stainless steel with undercut stems (will use SBC springs,etc.)
VLVTRN: SB Chevy springs, retainers, guides, keepers, locks
CAM : 0.488” lift AMC cam 218-degrees at 0.050” lift
LIFTERS: Rhodes anti pump-up hydraulic lifters
ROCKERS: 1.6:1 aluminum Roller rockers
OILING: Stock Oil pan. External valley oil supply line for rear mains. New timing cover with Nickle-plated Bulltear Oilpump cover at Hydro-relief gears
HEADERS: Edelbrock TES Headers for the Jeep Grand Cherokee/Wagoneer into 2.5” single exhaust Dynomax muffler
BOLTS: Milodon Main & Head studs
INTAKE: Offy Dual-Port 360 intake manifold. 1” Poweraid helical bore spacer. Torque-Plus intake gaskets.
CARB: Holley 670-cfm Street Avenger with quick-change jet bowls
CLD AIR: Aluminum 3.5” Cold Air intake for Dodge Dakota with GIGANTIC Cone filter
IGNTN: GM HEI distributor. Bosch Super CU 3-prong plugs (W7DTC). HEI wires

327 V8 STROKER SPECS: 3.82” x 3.82” x 3.574” x .7854 x 8 = 327.7 cid (bore x bore x stroke x percent x #cylinders = cid)

I found a near perfect piston for use in my stroker build up, as well as for use in a stock 304 build-up, should someone want to use a stock crank/rods (not 390 parts). It's for a Ford Pinto 2300cc that has a stock bore is 3.78". Cost runs $111 for FOUR Keith Black pistons at Summit Racing in any size. They have 4.5cc opposing valve reliefs, come with floating pins, spiro-locks and are weight-matched. Here's a couple of links :


http://kb-silvolite.com/performance.php?action=details&P_id=241 (piston details)

http://store.summitracing.com/partdetail.asp?part=UEM%2DKB217%2D4&autoview=sku (3.78" bore x 4 ea)

http://store.summitracing.com/partdetail.asp?part=UEM%2DKB217040%2D4&autoview=sku (3.82" bore x 4 ea)


Two things are needed to make the Ford Pinto pistons work:
1) Bush rods for Ford 0.912 wrist pins (can fit on 390 and 304 rods)
2) Possibly have to re-cut 1 or 2 valve reliefs in pistons.

Since my 304 block is currently at 3.78" (0.030" overbore 304), if I run the STD bore 3.78" Pinto pistons, I don't have to bore (or deck) my 304 block, as it's at 3.78" now and decked 0.010" for O-rings. Likewise, I don't have to turn my 390 crank and buy different rod bearings.

However, I want to have the block bored to a 3.82" bore (0.040" Pinto oversize ... 0.070" AMC 304 oversize), since it would make an AMC 327(.69") and I could then it would be fitting to run Rambler or Jeep 327 emblems on the sides of my Grand Wagoneer, LOL!

Since my block is decked 0.010" already, the stock 390 rod at 5.79" = 0.031 to deck and yields 8.76:1 (62cc) or 9.04:1 (59cc). Because the 390 rods must be bushed for the smaller Ford wrist pin, I can use my current 62cc heads and get 9.21:1 at 0.005" deck or 9.31:1 at Zero-deck, by offset bushing the rods. I have to measure my exact deck height to know how far to offset bush the rods. Initial cost estimates for having this done range from $240-$280 at the cheapest place recommended, so far.

If someone wanted to build a stock 304 build, with the stock 9.208" block height, a stock 304 crank/rod combo yields a 0.023" deck clearance and 9.0:1 compression, with the .045" thick ROL gasket and a 59cc stock 304 head. If the H-beam 5.885" AMC 360 rods are run (re-bushed to Ford pin) and the deck is milled 0.010", then it would yield a 0.003" clearance and net 9.4:1 compression with a stock 304 59cc head. Of course, the 52.2 cc 1970/71 early 304 heads could be run to raise compression another 0.50, to 9.9:1.

Also, if someone wanted to build a stroker 304 with 390 crank and 68/69 390 rods (like I am), they could also mill their block to get the correct height and not offset bush the 390 rods. The rods still have to be bushed for ford wrist pins, though.

331-cid is the largest the 304 stroker build can go, with the stock 390 crank 3.574" stroke. This is with a 3.84" Pinto piston (0.060" over Pinto 2300cc).

Now, to start gather needed parts for the final build!

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper