Muscley MOPAR
Well-Known Member
ive got either 65cc or 70cc open chamber heads with flat top pistons what would my compression ratio be for both cc's somethin like 10.1 10.5
w2 head compression ratio
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1970Duster
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Kind of missing a bunch of info to figure that out. Say like, bore, stroke, rod length, etc....
Muscley MOPAR
Well-Known Member
well its a .20 over stock rods stock stroke flat top piston360 wit open w2 heads, basically i wanna make sure i can get at least 10.1 compresion wit this open chamber w2 setup
what is the deck height on the pistons...how much are they down in the bores?
http://www.kb-silvolite.com/calc.php?action=comp
http://www.kb-silvolite.com/calc.php?action=comp
Muscley MOPAR
Well-Known Member
not sure i dont hav them installed yet cause i dont wanna install them if their gonna be under 10.1 compression all i no is that their flat top forged wit stock lenght rods otherwise ill hav to go to a dome style piston but then i might be into race fuel area
Your asking us to mind read and look into a crystal ball. You need to have info on hand for such questions. Otherwise, you may be better off asking when the aliens are landing.
IF the piston sits at a zero deck height, then a OPEN CHAMBERED HEAD AT 70 cc head with a gasket of approx. 4.125 X .039 will give a ratio of 10.48
Ditto above except, A CLOSED CHAMBERED HEAD @ 65 cc's would be a ratio of; 11.13.
If the pistons do not come to a zero deck height, mill the blocks deck down to meet the needed height of the pistons in the block.
Which means, you'll have to install them or have the engine blue printed by a pro, which is a lot of money compared to just a simple install of one of the pistons.
IF the piston sits at a zero deck height, then a OPEN CHAMBERED HEAD AT 70 cc head with a gasket of approx. 4.125 X .039 will give a ratio of 10.48
Ditto above except, A CLOSED CHAMBERED HEAD @ 65 cc's would be a ratio of; 11.13.
If the pistons do not come to a zero deck height, mill the blocks deck down to meet the needed height of the pistons in the block.
Which means, you'll have to install them or have the engine blue printed by a pro, which is a lot of money compared to just a simple install of one of the pistons.
Muscley MOPAR
Well-Known Member
well ya i get that thats why i was asking for a ball park estimate im sure theyll either be flush wit the deck or come over a lil
Ha ha ha, well, that is the Est. of it with what is a typical Fel-Pro head gasket.
Fel-Pro has a .054 head gasket as well. It'll give you a 10.10-1 ratio, 70 cc head chamber, 10.69 w/a 65 cc head.
Also, I corrected the ratio above in the first post since I goofed with a 4.00 inch bore to calc when you said it was .020 overbore. There is a slight rise in ratio that has been corrected in the first post. The all ratio's above are correct for a .020 overbore on the 360, stock stroke.
Install a slug and rod to see where it will sit in the block. If your wrist pin is a floater, the slugs can still be sold as new. They were just test fitted.
Fel-Pro has a .054 head gasket as well. It'll give you a 10.10-1 ratio, 70 cc head chamber, 10.69 w/a 65 cc head.
Also, I corrected the ratio above in the first post since I goofed with a 4.00 inch bore to calc when you said it was .020 overbore. There is a slight rise in ratio that has been corrected in the first post. The all ratio's above are correct for a .020 overbore on the 360, stock stroke.
Install a slug and rod to see where it will sit in the block. If your wrist pin is a floater, the slugs can still be sold as new. They were just test fitted.
Muscley MOPAR
Well-Known Member
alrighty thanks for the info
You got it, have fun. :thumrigh:
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