What engines would be more compatible to swap in my 1986 Buick Regal?

I have a 1986 Buick Regal with the Oldsmobile 5.0L 307 cui engine. The engine doesn't essentially give me enough power I'd like so I'm looking at putting in either a Oldsmobile or Chevy 350, possibly an even larger engine. I'm well aware of the differences between the 2 makes of engines (power wise and their design) but overall which choice would be the most compatible with my Regal, or should I look for something a little bigger or smaller? Hoping to be in the mid to high 300hp range.|||I have a Olds 350 rocket in my 78 Monte. It is really torquey. I've heard the olds blocks have a higher nickel content in them which makes them stronger (which ones, I am not sure, probably the older ones).


It depends on if you want to keep it all olds, or not. The best $$$ spent are usually on a chevy 350. You can make more HP easily with that for less money. It also depends on what bolt pattern your trans. has.


Some have a universal bolt pattern, some don't.|||It depends on what you want...





Do you want it to be just like stock?





Then I'd go with an Oldsmobile, Cadillac, Buick or Pontiac motor. They will all bolt up to your transmission (which I assume is a 2004r).


You could go with a Cadillac pfi 4.9l and swap the intake with a custom cam. An Oldsmobile 350 all the way to an Olds 455 v8. A 3.8l v6 from a mid 90's Camaro or Firebird would also bolt up to your transmission but would require a manifold and distributor swap to work. This would give yo a little better performance then the 307 olds (smog motor).





Better then stock...


You could also go with something like a Cadillac Northstar V8, Tuned Port Injection 305 or 350 v8 or a LT1 from a 1993-1996 Corvette, Camaro, Impala SS, Caprice, Roadmaster or Fleetwood.


Or you can go even further with a 5.3 or 6.0l generation 3 or 4 motor.


All of these will require a lot of wiring, fuel system, transmission and rear end changes.


But will be well worth it in the end.