hi guys whats the biggest valves i can put on stock 89 305 tpi pistons?

i was lookin at heads with intake valve at 1.940 and exhuast at at 1.500

are 1.550 exhuast valves to big?

You don't normally need an oversized exhaust valve. The piston's upward movement will always push all of the exhaust gases out of the cylinder. A smaller valve just increases the velocity. I know the 2.02 intake is too big for a 305 bore. When using a 2.02, the common exhaust size is 1.60. Chances are the 1.55 won't be a problem.

The pistons are not the problem. It's the bore size. The tiny bore really limits the size of the valves.

thx for the info man!