What will fit?

i have a 97 bonny, hydro-locked @ 3 weeks ago, i have pulled the intake plenum and manifold, cleaned the water out and reassembled, twice. (installed a new plenum the second time, with different EGR tube, hoping the degraded plastic plenum was the issue.) Apparently not. This time the engine started and ran ok, but blew lots of white smoke and when i pulled the dip stick, again i have water in the oil.
the question is: what year engine can i put in this thing? Mine has 126k on it, why buy a used engine with that many or more miles on it? Can I buy, say a 2000 and use it?
Call me cheap, but it's paid for and i simply cannot afford more car payments.

Did you change the oil and see water in it again? LIM gaskets could cause this also. Call any salvage yard, they have the interchange answers.

The series III will fit,same bolt pattern and the book is wrong on this.You have to change the intake manifold,upper intake and I heard one guy did this so far

i have a 97 bonny, hydro-locked @ 3 weeks ago, i have pulled the intake plenum and manifold, cleaned the water out and reassembled, twice. (installed a new plenum the second time, with different EGR tube, hoping the degraded plastic plenum was the issue.) Apparently not. This time the engine started and ran ok, but blew lots of white smoke and when i pulled the dip stick, again i have water in the oil.
the question is: what year engine can i put in this thing? Mine has 126k on it, why buy a used engine with that many or more miles on it? Can I buy, say a 2000 and use it?
Call me cheap, but it's paid for and i simply cannot afford more car payments.

First are you sure the lower intake gaskets aren't history? The lower gasket failure is a common problem much like the upper intake.. When we do an upper intake we highly recommend doing the lower gaskets with GM aluminum gaskets...

If you are going to pull this engine.... Is there an LKQ local to you or at least within a reasonable distance from you?

Next, Look for a Vin 2 3800 series III L26.. You will be able to use the the series 3, you will have to bolt your current parts to the motor... The series III uses a Dampolator balancer, this keeps the motor smooth throughout the rev band.. Next the series III has slightly better flowing heads, Forged Connecting rods and Molly coated pistons.. Its an all around good motor... and can be found with low miles.. The good thing is that the engines have the same service balance, meaning that you can used the old flywheel on the new motor..

This 3800 can be fond in the Buick W bodies, as well as the Pontiac W Bodies through 08 iirc..

A good friend just did a swap to the L26 Series III on his 97 SSE NA Bonneville, I did this as well on my 95 Transport.... so far we both like what we see in the series 3 engine and it is more refined over the 97 Motor..

I bought my 06 Series III L26 for $250 with 40,000 miles on it... My friend bought his 08 Series III L26 for $450 with 2000 miles on it...

If you have any questions please feel free to ask..

Appreciate the responses; to answer the LIM questions, I replaced them the 1st time thru, although with the standard style gaskets. I am very simply a (cheap) "shade tree mechanic", even in this day of internet and EGR systems, and i am doing a lot of "assuming" on my car.
I believe (hope?) I have narrowed the issue down to either a cracked head or a cracked block. I reckon I will start pulling things off and having them checked, or simply start a search for a Series III and stuff it in...the body is in good condition, and I'm pretty sure the old girl will probably last as long as my "new" ride, a 91 Olds Royale with 16?,000 on it. (hey, it started right up, after sitting a while, the A/C works, it was $250.00 cash, I have the manual..... oh, yeah, there's no coolant in the oil!)

If you have an LKQ it may be a lot cheaper to find a newer L26 and just drop it in as opposed to fixing what you have... And I know exactly what you mean.. I hate car payments... It took me a lot to pick up my 03 Bonneville because I hate payments... I like the "its paid for I own it" phrase.

the job is done, the beast has been tamed. my 97 Bonny is parked in the drive, idling smoothly with no smoke and NO, pardon me, no water in the oil. 6 weeks? 9? i forget. New plenum, checked both heads; very, very careful and meticulous reassembly. for a lousy mechanic, success. thanks to all for the inspiration.

:confused: Where was the leak?