[427tall]

I have a 427 tall block, going to put a 4.250 stroke crank .060 over and 6.535 rods, do i have to use pistons that match the stroke and rod lenght or can i use any piston as log as the compression height fits?

thanks

[Rogers Performance]

You need to cal. the compression height.

[pdq67]

10.200" - .025" - 2.125" - 6.535" = 1.515" compression height!

Right Mike??

pdq67

[427tall]

Ya, i did all that fun math to figure out the comp height, ended up calling Competion Products and they said i had to buy pistons that fit the stroke and rod lenght, couldn't just use a pistion that fit the comp height, it had to be fore a 4.250 stroke and 6.535 rod, thanks

[GOSFAST]

That's a very popular combination out our way built with a 10.180" deck. Shouldn't be any reason you can't make an easy build without custom ordering any parts. Thanks, Gary in N.Y.

P.S. If you checked it all out you should be around a 1.520 C.H. These are stocking pistons among many builders. You'll get about a 10:1 C.R. with a standard 118 cc BB head and the +.400 rods!

[Larger Dave]

Compression height gets the piston to the top of the bore (which is a good thing) but it has to match the stroke and rods also because other wise the crankshaft counter weights will pass through your piston skirts (that's a bad thing). So both answers are correct.


Larger Dave