Are the 2000 ssei motors and 3800 series II from a 98 grand prix similar. I know the obvious like one na one supercharged and so forth. But could I build up the heads of the na motor and then swap them onto my supercharged motor. This is the thing. I dont want to have the down time of building my motor up. Can I use the block and heads off the 3800 series II and then put the supercharger and such on it?

a few minor differences HOWEVER it must be a supercharged Grand Prix, the l36 motor will not work to well.

main problems are the motor mounts and alternator mount...harofreak00 just put a motor from a grand prix into the bonnie with minimal headaches overall.

Thanks for the quick reply. Do you know if the heads are the same?
What about the throttle body. I havent got to look at the motor yet so I may be missing the obvious.

The blocks, and heads are the same. The TB is the same, the supercharger is the same. Everything on the motor itself is the same with a few execptions. The MAF sensor can vary year to year. The harmonic balancer from an H-body is superior to that from the W-body.

Accessories and coil brackets and mounts are different though.

This is comparing L67 series II to L67 Series II, L32 Series III motors are different in regards to internal rods (although compatible) lower intake, supercharger, and TB.