So I bought this 85 Trans Am with a 355. Not being someone who swaps engines alot, I'm trying to find out what has been changed, or should have been changed, to make sure its going to run allright. For example, the radiator. Does it need to be upgraded for the new engine? (Car had a 305). How can I tell if it has been upgraded already? Will the standard 9 bolt rear hold up to the engine?

Then theres the tranny. It appears to be the stock tranny after doing some checking. Is this 355 going to tear it in half?

For that matter, I'm not positive the engine IS a 355, thats just what the previous owner told me. How do you tell? And when I go to buy parts, how do I have them looked up? What came with a 355 stock?

 

A 355 is nothing more than a 350 with a .030 overbore, So nothing came stock with a 355,only 350s.

In order to tell if it's a 350 block you'll need to look at the rear of the block where the transmission bellhousing mates to the engine. On the driverside there will be a series of numbers, write them down then check on mortec.com or post them here, somebody will decode it for you. If it ends in 010 chances are it's a 350.

If the car doesn't run hot you shouldn't worry about a new radiator, unless of course you want a shiny aluminum one.