3.4L in a van...need help

[northstar46l]

1998 Olds Silhouette van [3.4L LA1 engine] bought cheap. Thought it just needed intake gaskets. Needed cam, lifters and valves. Engine rebuilt somewhere a year ago...badly. Took intake bolts out by hand. Valves stems ground so short there was no preload on lifters! Some lifters came apart. I would like to know if I can use a 2006 FWD 3500 engine in this van. I can get a good used engine for $450. What would need to be changed other than throttle body to make this work? OR should I get a set of used 3400 heads and use the 3500 intake?

I have 30 years experience in new car dealerships but I only worked with Buick 3800 supercharged for more power [like 450 hp and 525 lb/ft. in my Grand Prix]. This engine is new to me. Since I need so many parts to fix this 3400 of mine I might as well get some more power out of it if I can.

Any help would be great. Please steer me the right way. Thanks, Linn

[MidnightriderZ24]

if u worked with 3.8's how did u not come across a 3.1/3.4intake gasket?? 3800's are worse for intake gaskets.. but anyways, sounds like they drove with no oil lol. old lower intake gaskets used to be loose when doing them (only when original gaskets). check the rear headgasket, it could be blown/leaking too.. id slap 3500 heads/intake and run it till the old bottom end blows, and then swap over to a new/used 3400 engine if it does start knocking.

[northstar46l]

I was well aware about the intake gasket problems on the 3400 and was ready for that. The oil had coolant in it and so I had it towed home. What I did not realize was how bad the year old rebuild was.

When I boost the output with 3800 Buick motors I am working with an all aluminium intake system which never leaks coolant. The plastic intake on the 3800 NA motor is well known to leak.

If I was to use the 3500 intake and heads on a 3400 I give away a little in the compression area right? Do the heads/intake make up for that? On the high performance Buicks we run 9.5 to 10 to one compression then add a supercharger. If the static compression is higher than stock 8.5 to one we can run the supercharger slower so the outlet temperature is lower.

Are there enough changes in the 3500 motor that I can not use the complete 3500 motor out of a 2006 Uplander?

Thanks for the help, Linn