New member with top swap & exhaust questions

[not_a_gtp]

Hi everyone! I have been reading for awhile but decided to register today... I have a 96 GP with a 3100 and want to do a top swap with 3400 heads, LIM, and maybe a 3500 UIM. can I use the 3500 UIM without issue or should I go full 3400 top swap instead? I would also like to use the 3500 "header style" exhaust manifolds if possible. I work at a junkyard so parts come somewhat easy. sorry if I sound kinda dumb but Ive never had a 60* apart before (I had a sunfire before this car). Also, are there any companies that make an exhaust for this car or am I gonna have to custom fab one?

Any suggestions would be appreciated.

Thanks,
Matt

[MidnightriderZ24]

go 3400 heads,intake, with an upper 3500. port the 6 "runners" of the 3500 intake and u have a nice breathing 3100! im up in appleton, and ive got a ported set of 3400 manifolds for diiiirt cheap if youre interested even though i see you work at a yard.

[RedZMonte]

no aftermarket exhaust other then custom availible. you can order alluminized or stainless mandrel bends from summit/Jegs/ect... as well as straight 5-6" straights, i suggest you order the bends, straight, mufflers, cat (if your going to run one) and piece a custom mandrel setup... 2.25" or 2.5" is all the bigger i would go.. You can get a borla catback for the 1995-99 Monte carlo and have it modified to fit your car, you will have to change the hangers and maybe a couple bends back after the Y to the muffler to make it fit. I think mark at O.E.M. makes exhaust for the Lumina Z34's, which should bolt up or close to it. my recomendations:

Cat-Carsound/Magnaflow
Mufflers-Magnaflow or Borla
Resonator-Magnaflow
Tips-Pollish Stainless (your choice of style) (stainless doesn't rust out)

S

[not_a_gtp]

thanks for your help so far guys! I am still trying to figure out whether or not I am able to use the 3500 exhaust manifolds or if I need to use the 3400 ones with the crossover pipe. Also, what gasket set should I buy when doing this?

[not_a_gtp]

AND, how much change in compression will I see by doing the top swap?

[not_a_gtp]

go 3400 heads,intake, with an upper 3500. port the 6 "runners" of the 3500 intake and u have a nice breathing 3100! im up in appleton, and ive got a ported set of 3400 manifolds for diiiirt cheap if youre interested even though i see you work at a yard.

Just outta curiousity... how much for the manifolds? any pics? I can get stock ones where I work really cheap, but obviously not ported ones... Depending on what this whole project is gonna cost me, I might consider it.

[IsaacHayes]

Compression wont really change much. Chambers might be a little bigger/smaller but still under 10:1 and above 9.5:1... So stock compression...

3500 front will probably fit the front, weld a flange to a pipe and route it over the trans like the stock cross over. The rear may or may not fit a W body. But others have used a front on the rear as well, then joined them. 2.5" Exhaust mandrel bent will work fine, I have that on my modified 3100 and it does not kill any low end and will support many mods to come...