1995 Bonneville SSE-- I have to replace my engine. Found a 2001 impala 3800 with 11,000 miles at a junk yard. How difficult or possible would it be to match this up with the bonneville??

You'll need your Exhaust manifolds and fuel lines and such but otherwise its' the same engine, save some parts that have been modified for duarability (upper intake).

Make sure you keep your tranny dipstick tube as well!

Keep your trans, too. They won't swap. Also the Bank 1 O2. Not sure about Bank 2 on that year. There may be more misc pieces, so don't ditch the old motor until you're done.

Thanks for the info-we will be getting into it this weekend.

i'm halfway hijacking the thread, but when replacing an engine what would be the best tradeoff between reliability and affordability? i.e., a newer stock series II (do they beef them up more these days?), a year-for-year identical that may be higher mileage or use lower grade parts, or a custom option like a remanufactured engine with aftermarket components? assuming a guy like me was gonna do some moderate to heavy modding (intake, exhaust, cam, rockers, computer) what is the best buy out there?

There is virtually no internal difference between a 95 L36 and 2003 L36. Only some external stuff. Sensors, exhaust manifolds, etc.

Keep your H Body motor mounts as well. Impala'* for example use totally different mounts.

and your 95 UIM won't leak