With those old Venola pistons,given the width of the piston/wall clearance they use,I'd say .040-.048 range would be about it.I'd suggest .040 Cometics would be the ticket here.You're right,you can't [or shouldn't ] use steel shim gaskets with aluminum heads.
Identifying 409 Pistons
- Thread starter 88m5
- Start date
It'll run pretty good,but according to Eddies published flow charts for the unported versions[stock],they'll work best with a duration at .050 with a slit duration of 6-8 degrees more on the exhaust than the intake.What is the casting number on your block?
88m5
Well Known Member
I called Lunati and the camshaft they are recommending is 234/244 @.50 525/534 lift with a LSA 112 that is on a 10.5 compression motor he said 11 compression would change it a little. The one thing they are worried about is I really dont know what my compression ratio is because I could never find out who made the pistons. One person at Veniloa said it was theres but no info and another one said it was not there piston. So the want me to cc the cylinder and there is a formula to calculate the compression ratio. Does anyone know what the formula is? Also other than the CC of the cylinder what other information will I need to know? I know the piston sits in the hole .008 from the top of the block at top dead center I know the bore 4.342 and stroke 3.50 , the Edelbrock heads have .16cc. so not sure what other information I would need.
