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With those pistons at 17cc dome, the heads at 112cc chambers, you'll be in the area of 9.55:1 static compression ratio. This will leave you short at least 3 full points of SCR to deal with that cam. It needs 12.55:1.
Sorry, I'm late on my answer. Looks like everyone else picked up on it also. Last edited by techinspector1; 12-03-2012 at 02:34 PM. |
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So which piston should I go with for the stock crank size? Since the 4.00 crank is a nightmare combination
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I think the 315 are the hot ticket with afr heads. Yeah the little ones will make good snap but if your shooting for 500+ why not go with the bigger heads. But i understand cost can be a killer.
Heads, compression and cam all work together and need to be selected with each in mind. Cam needs big compression so you will need better pistons im sure afr may have some recommendations. Once you got the heads figured it should all fall into place. get pistons that match the shape of your heads so they will fit the chamber correctly and not have clearence issues or poor combustion issues. With dome pistons its important to get the shape right. Dont stroke it or bore more than one normal over bore for new piston install. You can make that kind of power with a 383 so with the 396 in race trim it should be pretty easily done with the right parts. Make sure the rotating assebly can turn at 6k rpm or more and not come apart. At that rpm level you will be able to make plenty of hp as long as the heads and compression can support it. you will notice i did not add any part numbers i am not expert with the 396. And wouldnt want to guess at parts that may work when you really need to hit it right on. I would start buy calling afr and asking if they had recommendation on the type and shape of the new pistons. They can atleast explain the combustion chamber so when you call the piston manufacturer you will know what type of pistons you need to ask for and go from there. Some of the other guys on the site can surely help more. Last edited by hcompton; 12-03-2012 at 06:29 PM. |
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since shoving the 4.00 crank in there is risky business im looking at this crank
Callies Compstar Crankshafts BB3425-CS - SummitRacing.com and the builder that suggested the cam also suggested some of these pistons and gave me the part numbers for them wisceo pto39h3 pto39h6 KB 9949 |
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454 crank into 402 build 550 hp goal
Building your engine with the 396 Callies crank and these Speed-Pro forged pistons will have a compression ratio of 11.372. A set of Scat I-Beam rods with L19 rod bolts should hold the pistons to the crank. The DCR will be 8.830 which means you will probably need 100 octane gas. Speed-Pro Forged Pistons ZL2242NF60 - SummitRacing.com Get the Afr heads with the 109cc combustion chamber. When assembling the heads make sure you use modeling clay and check the valve to piston clearance on each cylinder. I really like the Crower 01486 solid roller to go with this bottom end. .651/.677 lift and 260/270 duration. 107 LSA and 103 ICL. The 11.372 compression will work with this cam. Try to assembly the valvetrain with the lightest materials. The 396 and 427 engines like to rev high rpms so get the best lifters you can. Also adjustable guide plates and heavy wall hardened pushrods will be needed. A Edelbrock Super Victor intake and a Holley 1000cfm carb with annular boosters should top it off.
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First, whoever told you you couldn't make a 396 go 10s, well, NEVER ASK THEIR ADVICE AGAIN! There were 10 second street SS396 Chevelles in San Bernardino in 1973. Rowdy puppies, but got the job done!
The "428" is a great combo for a truck. It's basically the same bore/stroke combo as a 428 Pontiac, and when you use a 366 block, you get the "long" rod and it ACTS like a 428 Pontiac. The shorter rod required in the short deck would make for quicker revs but at the cost of some torque. For a street machine, it would be good for one that didn't eat as much gas as a "big" motor. Wouldn't go as quick, either, but still be fun. If the crank is a "real" 396 (the one you now have), the forging number is 6223. If the "parting line" is real skinny (casting), it's a 402 crank and not suited for any real power. If you have the forging, a MUCH better approach would BE the original stroke. Those heads would easily feed a 396 well past 7,500. THAT is the short-stroke BBC's advantage. It can rev 'til the cows come home. Yes, bigger can be faster at a more mild level. But NEVER underestimate a 396 or 427. Just when you do, they'll jump up and bite you! Jim |
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With the amount of money you are spending , you could build a 496. So, I would use the crank you already have. 500 to 550 hp is fine for a stock 396 or 402 crank (cast of forged). Short burst of full power is much easier on the engine as compared to long durations.
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polish the rods and add arp bolts and resize.. maybe bush the small end. spend your money on good pistons and roller cam.. bbc rec port heads off a 454 or even oval ports will do . no need to spend big money on new aftermarket heads.. if it was me, I'd look at the date codes on the block and head you have.. and the engine code and maybe sell it to a guy thats retoring a car that needs a correct date parts.. then get a 454 and build it or make a 489/496 with the money you plan at throwing at the 396 with all new parts you'll still only have a 402. if hell bent on the 396, you don't need new parts, use whats there.. get good 454 iron heads and rebuild them.. no need to drop 2000.oo on alum heads for a 396.. of $$$ crank/rods it's a little odd that you are say'n 454 cores are costly but want to buy 2000.oo+ heads and 1000.00 in roller cam+ new crank/rods ect into the 396 my 454 was 800.oo but it was a running fully dressed engine.. |
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454 crank into 402 build 550 hp goal
Where do you live? I will keep an eye out for one if it's near you.
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but all most all over the us of a, you can get mid 80's truck with 454 rotting away for under 1500.oo running. |
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I contacted AFR today, via email and phone number, just waiting on them to call back to reccomend stuff with their heads. I also contacted Brodix i've heard theyre the way to go for big blocks
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