changing base gasket

[copskahn]

About how much would it lower the compression by changing the base gasket from .012 to .020 on a gen 1 busa.

[Johnnycheese]

stock should be 10
my books are not in front of me but I do think it was .2

[Professor]

I calculate .25 to .3 depending on what stock is ranging from 10:1-10.5:1 actual to the 11:1 advertised.

[copskahn]

Thanks for the info..I have a set of 13.5 pistons ready for install and wanted to drop the comp a bit.

[OB_John Noonan]

Thanks for the info..I have a set of 13.5 pistons ready for install and wanted to drop the comp a bit.

Before you poll it apart, is your 13.5:1 pistons dome or flat tops..?

Whose are they (manufacturer) New or used..Price?

John

[copskahn]

JE 13.5 pistons.

[OB_John Noonan]

Are they flat topped?

Trust me this is a very good question...if they are flat tops with the standard valve pockets they cannot be 13.5:1...unless your head has been milled a bunch..

JohnwhoworkedforJE10yearsanddesignedallofthebusapistonsupuntilearly2008

[copskahn]

They are dome pistons

[Jay]

If it is not a pent roof forging, you can just machine the dome off. Will help flame travel too.

[OB_John Noonan]

If it is not a pent roof forging, you can just machine the dome off. Will help flame travel too.

Do not machine the dome off of any piston until you verify the current dome thickness and how much you may need to remove.

I have a 1397cc 220 hp JE pistoned Busa and like the power, for another $400.00 dollars or less you could have gone with a 1363 or 1397cc kit..

Either way I am sure you will enjoy whatever power increase you will gain.

John