Thread: UGH, Piston help!!!. searched forevaa

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I'v been LIterally searching for hours and i cant find one!!!

ok

Need Forged piston

72CC head, 350CI, .040 over, 3.750" Stroke, 5.7" or 6" rod. NEEDS to be 9.5-1 Compression no lower or higher.

needs to be able to Hold built stroker + 200 Shot nitrous

thanks!!

PLease someone proove me wrong, and find me a piston that fits my Criteria, dont wanna custom order em from JE

Before I start a fire storm here, I like JE. I like Ross. I like Wiseco and so on and so forth. I prefer Arias and my best deals have been through Howard's. You can custom order with few problems from either side of the corporation. Stronger press proceedures upon forging and a really nice skirt. They are in no way a "Brick" by any means. Just my .02 cents worth. (No, I don't work for Howard's) Shop the National dragster. Online check etc. You'll do okay.

i'v searched JE,Wiseco,KB,SRP, Speed Pro, ETC and i cannot find a premade

9.5-1 compression FOrged piston, its driving me insane, i hope i just missed a few pistons. i Really dont wanna have customs made

Arias also dosent make them

You may be going about this the hard way. Let's find out what we MUST work with and then determine what we MIGHT ALSO work with. .7854 times 4.04 times 4.04 times 3.48 times 16.387 tells us that the cylinder volume is 731 cc's. We already know that the chambers are 72 cc's. So, we have 803 cc's that we can't change. Now, let's find a volume for the valve reliefs, piston deck height and gasket volume that we can equal 9.5:1 c.r. with. If we add 731, 72 and 14, we get 817. If we add 72 and 14, we get 86. Now, if we divide 817 by 86, we get 9.5:1 static compression ratio. So, somehow, we need to use a piston deck height volume, piston eyebrow volume and gasket volume that will equal 14 cc's. Now, on a flat-top piston, the eyebrows are usually about 5 cc's, so that leaves us to come up with 9 cc's. A gasket with a bore of 4.100" that compresses to 0.040" will contain 9 cc's. OK, we're there. That doesn't leave any room for piston deck height, so the block will have to be zero decked. Just by the luckiest of coincidences, we have arrived at the perfect static compression ratio and also the perfect squish figure (0.040" @ zero deck).

Hurray for our side !!!!!!!!!!!!!!!

Looks like a Ross or Lunati will work. They may or may not get you exactly 9.5:1 depending upon your deck and head gasket, but you should be able to land between 9.4:1 and 9.6:1. Both pistons look like they are stocked at various locations.

Lunati 1311G2S5 http://www.holley.com/1311G2S5.asp

Ross 99525 http://www.rosspistons.com/uploads/c...flat_top_1.pdf

Below are my calculations

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ross are already out for the count, Im using forced induction, 200 shot nitrous

you even think those Lunati could handle a built 385 with 200 shot nitrous?

Originally Posted by Superjustin13

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ross are already out for the count, Im using forced induction, 200 shot nitrous

you even think those Lunati could handle a built 385 with 200 shot nitrous?

Did you read my post? Use any forged flat-top piston with 5 cc valve reliefs. If you can't find exactly 5 cc's, let me know what you find and I'll figure the deck height for you to reach 9.5:1

Originally Posted by Superjustin13

I'v been LIterally searching for hours and i cant find one!!!

ok

Need Forged piston

72CC head, 350CI, .040 over, 3.750" Stroke, 5.7" or 6" rod. NEEDS to be 9.5-1 Compression no lower or higher.

needs to be able to Hold built stroker + 200 Shot nitrous

thanks!!

PLease someone proove me wrong, and find me a piston that fits my Criteria, dont wanna custom order em from JE

I hope you don't think this will run on pump gas.
I would never try it with the bottle on.
At 200 hp I would run a seperate fuel system for the gas solenoids with a hi-octane race gas.
Don't forget you can always "fly cut" and jockey you gasket thickness around to get the comp. ratio correct.

Justin, the answer was too long to go on a PM.

can you figure the compression Ratio using this piston? thanks[/QUOTE]
Sure. I'm assuming these are flat-tops with valve reliefs, right?
Multiply .7854 times 4.04 times 4.04 times 3.75 times 16.387 and get 788 cc's in the cylinder.
We know there are 72 cc's in the chamber and 5 cc's in the piston eyebrows.
We know that a small block Chevy is 9.025" from the centerline of the crank to the decks if the decks have never been cut. If we deduct the 1.425" of compression distance on the piston, 5.7" inches of rod length and half the stroke (1.875"), we are left with a piston deck height of 9.000", meaning that the piston will be 0.025" down in the hole at top dead center. Multiply .7854 times 4.04 times 4.04 times .025 times 16.387 and find 5.25 cc's in the piston deck height. Assuming a gasket with a bore of 4.200" and a compressed thickness of 0.039", we multiply .7854 times 4.2 times 4.2 times .039 times 16.387 and find 8.85 cc's in the gasket.

Now, add 788, 72, 5, 5.25 and 8.85 to find a swept volume of 879.1 cc's.

Now, add 72, 5, 5.25 and 8.85 to find a compressed volume of 91.1 cc's.

Now, divide 879.1 by 91.1 and find a c.r. of 9.65:1