Are all GM supercharged 3.8's the same? By that I mean is a 1992 Buick 3.8 the same as a 1992 Pontiac 3.8? Also, would it be compatible with a 4T60E tranny? Please give me some feedback because I was looking into a supercharged 3.8 in a 1992 Bonneville and was going to swap it into my 1991 Century. Would this work?

all 3.8s from that time period are the same and they will all mate with a 4t60. however, a 3.8 S/C will probably require a few other mods if you put it in a century, such as bigger C/V shafts, better motor mounts, new wheel bearings, and a trans fluid change at the very least.

Yeah they're all made by Buick so they'll all bolt up to the transmission but there are some differences. The Supercharged version came with a heavy duty transmission and a 2.97 final drive only. Other 60E's were available with 3.03 and 3.33 final drives.

If possible try to get a 93 l67. 1993 was the first year they used thinner low friction piston rings and roller fulcrum rockers with a 5/16th stud. They were rated for the same HP but many feel there is surely a difference.

For your reference the '92-95 naturally aspirated is known as the l27 and the supercharged is called the l67. L67 was also carried onto the series two engines, but they're a totally different animal.

Good luck on the swap!

Thanks a lot guys! I'll take all of your advice and will be sure to update you.