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Piston advice?

Started by Reidar, July 26, 2006, 07:12:36 PM

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Reidar

Hi guys!

I have a 75 charger with a 360 engine. Im trying to get this car to go as fast as possible, while learning in the prosess.. :)

The standard compression ratio on theese are 8,4:1
I was thinking of buying new pistons like theese: http://store.summitracing.com/partdetail.asp?part=UEM%2DKB190%2D8&N=4294908110+4294782068+4294925067+4294776514+115&autoview=sku

What will my compression bee then? Im thinking 9,6:1.. Is that right?

Reidar

John_Kunkel

You can't make a guess on CR without knowing the actual volume of your combustion chambers.

http://kb-silvolite.com/performance.php?action=details&P_id=15
Pardon me but my karma just ran over your dogma.

deputycrawford

Also, you will need to know the deck height from the piston top to the top of the cylinder, and the gasket thickness. Not to mention the chamber volume of the head. Money would be better spent if you turned the block and heads into the machine shop and had them cleaned first. The block will need to be completely machined and the deck trued, or squared. You will then have to figure how much to mill the heads until you get a straight surface again. Then get measurements of the rods you are going to use. Let the machine shop tell you what your compression is going to be. Then you can tell them to deck the block further, mill the heads or both. Then they will order or special order the pistons. Only then can you decide what compression you have.
If it ain't wide open; it ain't running.        Rule number one in motocross racing: Pin it; row the gear box; and wait until you hit something.     At work my motto is: If you need me, call someone else.

chrisII

the kb-104? flat top zero deck with stock 360 heads yealds 10.5 -11.0 according to my math a few years ago building a similar engine with fel pro permatorque gaskets , the best gaskets i found for sb mopar. i am guessing that those pistons you posted with the quench are going to be around 12:1 . they used to have pretty accurate compreshon numbers in the summit catalog. but it has ben about 5 years since i looked at them..be VERRY CAREFUL with ring gap on hyperetuctec pistons , especialy KBs. they are a great piston , but improperly gaped rings break em prety easly. a bit loose on the gap is better than too tight.