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304 making 405 hp with modified 304 heads

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Boris Badanov View Drop Down
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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/24/2020 at 10:18am
Obviously it made more than 93 hp at 3900
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2020 at 12:40pm
Boris, please check my numbers!

Streetable 304 close to 325 HP fairly cheap.

Looking for pistons with the 1.433" compression height! and correct bore!

KB186 piston is 3.736" STD so the over-bores 0.020" to 0.060" can be used, but 10cc dish. Will be 10.2:1 CR. That puts HP very close to 325 but the 304 head has to be used with the valve upgrades jcisworthy did with jcisworthy’s LS rocker upgrade.

Chev 6.050” rods, 18% to 20% less overall forces on crankshaft, main bearings and piston side loading.
Cometic 0040” head gaskets for 0.045” QH
Airgap intake. The JR Victor would put it over the 325 HP mark.

Cam lift needs to be 0.0510” to 0.0525” for the numbers to work.

See, got the bore wrong again with the lousy 0 on the laptop. You cannot bore a 304 to 4.000". Max bore on a 304 is 3.875".

You can get forged pistons for this combination also, easier once you define what you are looking for:

https://www.summitracing.com/search/part-type/pistons/make/chevrolet/engine-size/5-0l-305/piston-material/forged-aluminum?N=compression-height-in%3A1-433-in




Edited by Trader - May/25/2020 at 7:45am
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Boris Badanov View Drop Down
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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/24/2020 at 6:03pm
I really like that. I think 11:1 might work better.
I have a 304 and am thinking of a 4" crank in it.
That would make for a great station wagon motor.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2020 at 6:50pm
A 304 at 0.040" over-bore allows the 360/401 stock head without any notching, so someone else do the math on doing this with this rod/piston combination. 
It feels like being back in High School studying for a math test and you know you got something wrong. Enough math for the day!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jmerican Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2020 at 9:04pm
Without checking my notes... a 360 crank is not the 63 pounds as stated in this thread. More like 55.
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