Re: [Amc-list] AMC 304 V8 Stroker Build (327-cid AMC V8!) - Final Answer

[Greg Taylor <amundaza@xxxxxxxxx>]

Hey Wayne/Steve,
  Thanks for reminding me about the gross vs. net thing ... forgot about that, LOL!
   
  The Edelbrock heads would be nice to run, but have the larger 2.02 / 1.60 valves, which would facilitate notching the cylinder walls for unshrouding them.  I see you mention swapping the larger valves down to 1.94 / 1.50 in the Edelbrock heads.  Could be done, but would cost more $.  I'm not so much concerned for weight, after all I'm driving a Grand Wagoneer!
   
  My 304 heads are already ported, the chambers have been opened up to ~62cc and the bowls have been opened up A LOT for the 1.94 / 1.50 SB Chevy valves.  I'll be running the undercut stems (down to 5/16") for extra flow at low-mid RPM's.  This is what I ran on the 258 head in my Spirit GT and picked up GOBS of useable torque and power.  Made the 258 run like a 4.0L HO ... I estimate 30 HP improvement over stock 258.
   
  To address detonation issues, I am going to groove the cylinder heads, opposite the spark plug, angled slightly towards the exhaust valve side, since the spark plug is angled this direction.  The groove alters the quench area of the piston and the burn is directed through the groove down into the cylinder.  This altering of the burn has allowed 87 octane gas to run on higher compression engines, without detonation. as well as improved low-end torque, emmissions and MPG's (due to a better burn).
   
  I had remember hearing about this a while back and researched into and found some racing forum sites, as well as the discoverer of this.  Those sites are listed below.  I've been discussing the build and head mods with a guy that's been doing heads and grooving them for quite a while now, with great results.  He has built numerous racing engines that can run on 87 pump gas at 10:1 and 92 at 13:1.  He drives a '95 Suburban w/350 that he set up for 10:1 and 87 octane, in addition to the racing engines built.
   
  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 

  Thanks for the feedback.
   
  Sincerely,
  Greg Taylor :)  <><
   
   
  

stover@xxxxxxxxxxxx wrote:
  Not that it's crucial regarding what your engine is with the parts and
modifications it has but you are comparing apples to oranges when
comparing a mid seventies or later 360 rated at 160 horses net to a 210 to
225 gross horsepower rated 2bbl or 4 bbl 304/290. The 304 net with the
'70/'71 higher compression probably netted out at 132 to 135 maximum.
The stroker aspect with the fairly light pistons is a reasonable combo
for revvability. Optimise the flow/velocity through the heads and you
can get decent power. Personally I'd use the Edelbrock heads because
they have a superior detonation threshhold ( not holding up better once
it occurs but that detonation would occur under higher compression )
and a combustion chamber shape that promotes higher cylinder pressure.
You could get higher velocity flow and more flow at low lifts- though
you should shrink the valves down to 194ish/150ish and get get max
airflow through lift. Also the 50 lbs weight savings is that much less
weight to work against. True, they ain't cheap- but unless you've
ported iron heads already the difference is about 7-8 hundred.
Regarding the 290 SS/AMX- he's revving the pee-pee out of the motor and
if everything else were equal on the 401 equipped AMC's he wouldn't be
beating them.
Steve


Hi Davis,
I am building the 304 stroker, because I have nearly ALL of the parts
for it, and they are nearly ready to go together, and so, the trouble
and expense won't be all that much 'now', as compared to doing a 360
(which I have) or a 401 (which I don't).

I began engineering that stroker engine 12+ years ago and want to finish
it and get it running. It's been moth-balled for about 9 years, since
the twin-turbo race car project was nixed ... and it's time to finish
it.

Were I to start with the current 360 in my Jeep (60K on it), the cost
would be A LOT higher in rebuilding, especially to the specs that the
304 is built to. I looked into putting the 390 crank/rods into the 360,
to make a 383" stroker, but I would have more $$ to put into the 360
block to prep it. The 304 block is nearly done and the build up is
internally balanced, weight-matched on components and should make more
power than most would expect. Garrett Ghezzi's SS/C '69 AMX with a 290
v8 (0.060" over) can attest to that. He's pushing close to 480 HP and
just under 400 lb/ft torque with a super stock engine & square port '69
heads. He routinely beats out 401-powered AMC's with that car.

While I don't expect my stroker 304 to make that kind of power, I am
estimating that it will be in the 275-300 HP range and torque should be
quite nice for the Jeep.

Please note that my current 360 makes about 200 HP roughly, with 4-bbl
carb/intake, headers & single exhaust and a stock 8.25:1 producing a
whopping 160-hp (stock). The stock 9.0:1 304's made 210 hp and 10.0:1
290's w/4-bbl made 225 hp.

Sincerely,
Greg Taylor

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