I agree with both these guys to tell ya the truth but honestly i have three 3800 powerd cars an ln3(1990 buick) an l27(94 bonne se) and an l67(97 bone ssei) and my ln3 is def the slowest my l27 is faster than the ln3 but in no way than the l67 lol....i just pulled the l67 out of my bonne and am gonna get rid of the body then do a swap into my buick hahahahaah but the info i gave you was just me trying to help some without costin you a huge amount of money or time as i would assume the 88 is your DD

There was a turbo LN3 here a while back. It is absolutely awesome, and still running today. Not much power, but it is a cool setup.

Heads/intake
As rjolly said, you could do an L27 top swap. I suggest a 1995 Chevy/Pontiac minivan should supply you with parts because of the minivan demographic and also since that'* the last year of the L27. The intake would be plastic in that case, I think, but see if you can get a metal one. They crack less easily. That, along with some Yella Terra Series 1 rockers (if they fit), would work great.

Exhaust
An LG3 exhaust should be able to bolt right up. The LG3 came on the 86-88 or so 3.8L V6 engines, and it'* thought to be the engine that came before the 3800 as it'* called today. There aren't many interchangeable pieces, but the exhaust manifolds should work, and if they do fit, please switch over since they essentially are headers. Then, as mentioned, get a high flow cat and all that fun stuff.

Also, I suggest that you take out the cam that'* in there, have a shop figure out its dimensions, and then you should go to some place like CompCams or so and get a new camshaft from them. I don't know why anyone hasn't done that yet.

Well thats a real downer I am not going to do an engine swap on this car. I just want to make her more enjoyable because I know the LN3 engine has gotten great reviews as far as reliabilty and my car only has 79000 original miles so I would like it to just stay and last a couple hundred thousand for sure since the car was free. I will check into the exhaust I called a couple shops and the guys weren't real nice here where I live so I might just go into the next down and ask. Thanks I can always just make the engine bay pretty

Probably because for the amount of work and cost it would take to cam and tune an LN3 (and get minimal gains because the heads flow like crap), you could swap an L67 for a couple bucks more.

Let me try to give you an idea of how terrible these heads flow.

3100 (60*v6) heads flow better than S2 L67 heads
S2 L67 heads flow better than L36 heads
L36 heads flow better than L27 heads.
L27 heads flow better than LN3 heads.

A lot of this has to do with casting imperfections, the size of the valves, and the shape of the ports. You can smooth out casting imperfections with a grinding stone and a dremel and that will give a noticeable increase in performance, but you can't get around the fact that the valves are smaller and the ports were not designed to flow high volumes. If you get a cam, you'll get higher lift and duration, but your heads still won't be able to flow well enough. This is why the L27/LN3 is a dead end road, and why porting those heads makes such a big difference.

The L27 front intake manifold is basically the same design as a powerlog. It is much better designed than the Series 2 3800 front manifold, which is cast iron. Not sure what the LN3 has, but I'm assuming its the same.

Want to do an L27 top swap? I have a set of ported heads with lapped valves on 5/16" studs, and a ported lower intake manifold at my buddy'* house in Ohio near Cleveland. I just recently got a S2 L67 swap done, so if you want them, I'll let them go for dirt cheap.

Touché. That does explain quite a bit.

Will the Tb from the L27 work on the LN3. That is if i use the L27 upper intake. I have a 92 L27 that i'd like to use on a 90 LN3.

We are having good results with factory stock LN3'* here, we just had one go 11.7 @121mph on 15psi (T70 turbo on basic log manifold) and 222*/222* cam but with major traction issues with some 26x10.5 hoosiers.

the LN3 manifolds are completely different from the L27 (see http://en.wikipedia.org/wiki/File:38...bonneville.JPG ) which is why we want to try the L27 manifold.

I'm working on a set of LN3 heads, fully ported and polished using 1.77" in/1.5" ex stainless valves like the buick grand national heads GN heads (i think).

Found the info i needed. The L27 heads , intake and Tb will bolt up and work with very little work Porting them would be the best way to go. Need the fuel rails and injectors (with new o rings) which are 22lbs and LN3 are 19lbs. As far as i can tell my exhaust manifolds will work and the 92 exh look to be the same also.
I have the complete running car so no money investment into parts.
Do the 92 L27 heads have roller rockers ? Or 94 up only.

I be great full if anybody can hook me up a L27 intake of give me the contact details of someone who could. i've spent some time emailing various outfits with out luck

Try these two plenty of info here. Let me know how it goes. I want to finnish my suspension and tranny first before porting my spare L27 heads and intake. to swap over while i keep the car running.

viewtopic.php?f=1&t=3982
http://www.bonnevillepro.com/forums/...hp?f=36&t=7156