So I have an opportunity right now to get a buick road master with 80k miles on it from an elderly couple for a great price. my plan is to take the lt1 from the car and swap it into my '89 RS to replace my 305 with twice as many miles on it. What I'm wondering is if will be a comparable swap even though it's from a different model of car? I'm expectecting it to be more difficult that if I got the engine from another f body but the price is exponentially better. Any advice?

 

First, make sure it's an LT1, not an L99. L99 looks identical to LT1, but with a 305 bore diameter, a 3" stroke, and 5.94" rods.

 

The lt1 will be what it says on it's rpo sheet right like where mine says lo3 now?

 

What if someone blew up the LT1 by abusing it, then dropped in an L99? The casting number on the block is the only sure thing.
The one behind the left head is what you need.