how big?

[895.0]

how big of a cam can i go with before it colides with the stock 89 pistons?

[Mike Croke]

It's not the lift so much as the timing. You can run very low lift and still hit the pistons if the ramp rates are aggresive. There's also a great deal of variance in the manufacturing tolerances on engines which means no two engines are the same. What clears in one engine might not in another.

[embler]

+1 but if its lift #'s you want, I wouldn't go no bigger that .512. you start going real big, your going to need diff pistons anyway to put up with the power and powerband. size your cam accordingly. remember, bigger isn't always better

[stockhatch]

Depends, as mentioned above. I barely had enough clearance with Slightly milled E7s and an F-303 on stock 88 pistons. I was pretty close on the intake. Exhaust cleared by a mile. Aftermarket heads with valves larger than a pencil eraser will have even less clearance.

[Mad Max]

b303 and 1.7rr's is the biggest for me

[My85GT]

mine is a stock 89 block, and I am using holley alum heads with a E303 and 1.7 scorpion rockers. runs real strong.

[895.0]

thanks guys for all the input.

[MurPHy]

I'm using an E303 with 1.7s on GT40 heads, clears my '90 pistons just fine.

Clay it just to be safe. I didn't, and got lucky. You might not.