Too many miles

This is my first post, usually i'm reading through for advice. My 97 riv has 255,000+ miles with original engine and transmission. I absolutely love this car but am worried about it finally going out. I would like to replace both the engine and tans with an updated gm model. Such as a Grand Prix or G8. My car has a supercharger so the step up to a gen 5 would be nice. My question is what year and model of vehicle would be best to swap out the engine and trans into my riv.

Ideally you want the motor from an '04 or '05 GTP, those L32 engines had the GenV blower. You will need a throttle body adapter and your throttle body, or an N* throttle body because the '04 '05 had drive by wire. I would have your trans rebuilt by someone who knows these and select some quality parts from ZZP Performance or Intense Racing to supply the rebuilder with. The transmissions behind the '04 '05 GTPs are different enough that it's not worth the switching effort.

In all reality, the only difference between the L32 and L67 engines is the supercharger/LIM and cam design. It may be cheaper to rebuild your engine and pick up a Gen V blower, and install a good cam like S1X or XP cam.

Read through the 3800/Grand Prix parts sections of zzperformance.com and intense-racing.com

A lot of the performance parts can be bought in good used condition from clubgp.com's classifieds.

L26/L32 engines have powdered rods too.

What you really want to do is a compression and a leakdown test to determine if you really have a need. The Riv's 3800 engine has a VERY strong bottom end, if I remember right the design was well in excess of the car's power output. It should cost less than $150 to have a local mechanic do the testing if you do not want to/can not yourself. Search this site for "leakdown" to find the posts describing the tools and how-to for the leakdown test.

As for the transmission check the fluid and work from there. If it's not pink/cherry red it's time to change it, have it changed to Dexron VI is my suggestion.

If your car was well cared for to this point odds are you need neither a transmission nor an engine. Testing will tell you if there is a need then you can act accordingly.

Albertj