Ok here is what im thinking

[CLEVEN]

Ok i just got my 1998 Olds Cutlass paid off. 89,000 miles on it What i was wanting to do is get a little more power out of it. What i wanted o do is get a Lower 3400 intake, upper 3500 intake, Running a stock 3400 t/b . What i wanna know is what all i shall need for this swap i seen it done on some early3100's.

[SofaKingWeToddDid]

some wrenches.

[robertisaar]

metric socket set and a socket wrench..... and gaskets.....

doesn't get much simpler than that.

[CLEVEN]

Yeah i knew all that lol. Yeah iv done alot of research on this and went on alot sites. Been thinking of it and nowthat i got her paid off i might go ahead and hit up a pick and pull this weekend

[AaronGTR]

Well, if you wanna use the 3500 upper you're going to need a few more things than that. For starters you'll need the TB adapter to use a 3400 style TB. Personally I think you'd be better off with a 62mm TB but if you don't have the $ right now the stock 3400 will work. You'll need the 3500 map sensor as well or adapt your map sensor to the manifold. You may also run into clearance issues with the neck on the 3500 UIM and your fuel pressure regulator. Nothing that can't be fixed with a bit of grinding with a sanding disc. I'm sure there are a few other things.

[IsaacHayes]

Torque wrench is essential. Or you will have leaks with the intake manifold (epesially the lower).

Grab a chiltons/hanes manual. Need new injector o-rings too. Might as well port the new stuff before you put it on. You have roller rockers so the 3400 lower will fit right on no problem. there are a few other things, if yous search my topics I started tehre is a 3500 plenum swap thread. Some of the stuff won't apply to you like the rockers.

I'm running that setup and it's nice. I also have a 65mm TB and 2.5" mandrel bent stainless exhaust from the manifolds to the tail pipe with a high flow mangaflow cat and straight through ultraflow stainless muffler. clamps and hangers are stainless too


EDIT oh yeah go to dealership get a new oil pump shaft oring the brown high temp one. Replace that while youre there. Get the metal dorman or felpro lower intake gaskets. DONT mix up pushrod order or you'll have bent valves... After assembled and the RTV cured, fire up the engine till its a little warm, change oil then go for a drive.

[1988GTU]

Torque wrench is essential.

EDIT oh yeah go to dealership get a new oil pump shaft oring the brown high temp one. Replace that while youre there. Get the metal dorman or felpro lower intake gaskets. DONT mix up pushrod order or you'll have bent valves... After assembled and the RTV cured, fire up the engine till its a little warm, change oil then go for a drive.

Just use globbs of orange RTV and an impact gun, it'll git dun really fast!

[fbody_mike]

What kind of performance upgrade would the above net on a 3100?

[robertisaar]

since you're essentially turning a small port 3100 into a large port 3100 with a 3500upper, isaac would know best.

i'd say you could pick the motor up to a healthy 185HP with a large port lower, 3500 upper and 56mm TB. the stock TB probably won't go much farther than that, and the stock exhaust manifolds aren't helping any either...

so figure around a 25HP boost from factory parts...

[fbody_mike]

Hot Damn! This is going on my project list. Especially since I gotta due my LIM gaskets anyway.

[IsaacHayes]

With tuning at least 175hp, as that's what a large port 3100 runs. Depending on what exhaust manifolds you have too, and how good your exhaust is. Without tuning who knows. The 1/4 mile track was sold to apartment builders and there are none remotely (read within a days drive) close to me now so I don't know what I'd run now. But I'm not tuned, and the motor and trans have well above 200,000 hard miles on them... But it is faster. Either a fresh trans, a tune, or new injectors and my car should pull better. It pulls hard in some areas but not all (tuning), and is now dying off in upper RPM so I'm thinking injectors or trans...