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304 making 405 hp with modified 304 heads

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farna View Drop Down
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    Posted: May/20/2020 at 10:09am
For those who thought the 304 wasn't worth messing with... 405 hp @ 6700 rpm, 358 ft/lbs @ 5500 rpm. Not exactly a street motor at those rpm though! At 3900 rpm it's only masking 96 hp and 129 ft/lbs. Watch the video carefully! Hard to see the readouts, but the power and rpm levels I posted are close. I rounded to nearest 100 rpm and full hp/torque figures. Good small displacement drag race motor!

Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 11:10am
That link is not working and you have to be a member of that group to see any content if it was.

Maybe you could copy and paste the text?

Tom
1949 Ford Business Coupe
1969 AMC Rambler Rouge, Tube Chassis Race Car
1974 AMC Hornet Hatchback, Wally Booth Outlaw NPS Race Car Project
1980 Ford Fairmont Futura
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 11:48am
That sorta like the 63 split window vette, that had a fuelie 327. The guy set it up to turn in the high limits. Did not get much power below 4K. The 304 has huge breathing capabilities with valve and head work for high RPM use. It has a good stroke for either turbo or supercharging, if wanting more power. For that to pan out, it would be setup more like a traco 304, just smaller bores, when competing with 5.0L class. Though the larger bore, like the boss 302, is how to get a quicker charge over the stock bore of a 304. Probably why it's dead below 3500 RPM. Bigger bore would bring in the RPM torque band a bit wider. Though you can always push the limits on a 304 over bore to some degree. Drop in a 343 crank for a shorter stroke and see how fast 8K comes in.

I never disliked the 304, but for street and occasional strip use, it takes a bit to keep up with all the bigger engines, even more so with aluminum engines being common now. Out classed by weight and electronic / hydraulic controlled timing curves. Does the mighty 304 in.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AlexK Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 1:15pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: May/21/2020 at 6:30am
drop that one in a hole and backf fill it. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: May/21/2020 at 7:13am
Not a real practical build for sure...
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: May/21/2020 at 6:58pm
IMO the 304 yields nothing to the Chevy 302 except weight.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2020 at 2:14am
AMC 304 = 540 pounds, and sbc 302 = 510 pounds ?
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2020 at 1:36pm
Ok, so the short block is a tad heavier than the Chevy
The crank is also heavier by 10 lbs~
The crank is longer with 4.75" bore spacing vs 4.4 for the Chevy.
the 302 was internally balanced.
The oil system in the Chevy may be the best of the small block wedge head engines.
The intake valve angle is an old argument but the Chevy had a far better
short turn radius in the intake.

So I guess I may be wrong again...
But reciprocating weight and oil system along with a far better intake for
high engine speeds may be the reasons. But 50 lbs is still 50 lbs.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2020 at 9:41pm
Weight of the rotating assembly has a lot to do with the "math" of an engine, but the rod length to stroke ratio, compression height, quench, intake, valve size ... change things significantly.
Take the latest build from pipefactory's build example - 1.74 rod to stroke ratio - almost perfect for an old 60's, 70's engine. 1.75 rod to stroke ratio being the best "math" wise on a 2 valve per cylinder engine. Not surprised at all with the results, given the reduced weight of the rotating assembly.
The Chev 302 has better "math" then an AMC 304.
A stock AMC 360 has better "math" then a stock 304 or 401. Unless you stroke or change it and get closer to the 1.75 ratio. Here just displacement rules between a 304 and 401!
Old rule of there is nothing like displacement only goes so far before you loose the "math" battle".

Boris is correct, a Chev 302 wins the math battle.
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