I have a 1994 buick lesabre custom with the 3800 engine in it. Series 1 I think. I found an enigne and tranny from a 1992 pointiac bonneville and I’m curious if the transmissions will work out. I could just take then engine, but for a 88000 mile tranny, I’d rather swap both out at the same time. It’s my understanding that the engines should be exactly the same, but I’m less familiar with the transmissions.
My old engine got water in the heads and locked up. Next time I work on the car I think I’ll get the heads magnafluxed 
Thanks so much for anyone who replies
I’m no mechanic, but I’ve got a 91 LeSabre. My Haynes Manual covers 85 thru 02, and in there it makes no differentiation between 3800 engine types for 1992 on. It’s my understanding, however, that an engine mount moved at some point to be located inside the belt perimeter, so watch out for that.