On my stock block 305, the bore is 3.736. I can get gaskets with that bore (Summit# FEL-505SD) but Trick flow recommends Felpro# 1010 which is up to 4.155 bore. Is it okay to use the 4.155 bore gaskets with the 3.736 bore? The heads are aluminum 305 heads. Thanks.

You should use the gaskets that fit your bore.

World Products does the same thing on their 305 sr torquers. I think it's to allow clearance for the bigger 1.94 intake valves.

I went with what the manufacturer recommends, which is a gasket made for a 350 cu engine, the felpro #1003.

I think that there will be some compression loss due to the bigger bore gasket, but maybe they made up for that in the chamber design to begin with...