The lt-1 block will have a 5.7 stamped on the driverside behind the head(looking at the block from the top). It also has a 327 stamped on the driver side of the block under the head (would be behind/under the exhaust manifold). If it were my decision, I would probably put the heads on the Trans Am block. Even If you only see a few more hp. But you should check the tops of the pistons and cylinder walls to see which ones look better.

 

I was thinking the same thing, the transam lt1 would need a honing to be perfect and the Roadmaster would probably need a boring because it has the lip near the top of the cylinder wall.

 

Yes.. they have "327" on the side of the block. "5.7" can also be found in the top behind the drivers side head on the bell area