Hello!

I have a 1986 Camaro with a 2.8 MPFI engine which, sadly, pretty much needs replacing. Both exhaust manifolds are cracked and with the mileage on it, it's pretty damn sure bolts will snap if I attempt to replace them, skyrocketing the costs to way more than the engine is worth...

I am, however, buying a lovely, low-mileage 3.1 that has been rebuilt for performance. It comes from a 1992 Camaro, fits the same transmission, has the right exhaust manifolds - all is perfect.

Or is it?

Problem is, it's a TBI motor, and a few rather knowledgeable people told me to forget about it - as I would also have to get a new engine computer (basically the whole TBI setup), replace the fuel pump and miles of wiring. but... other knowledgeable people said that pretty much all I'd have to do in order to solve this problem is to swap the intake manifolds, as they're supposedly interchangeable.

Is that really the case? Will an MPFI manifold from a 2.8 fit on a 3.1 as a straight swap? I keep hearing that it's the same engine on the outside, but I need a clear answer...

Can you guys clarify this for me? Thanks in advance!

 

Yup they are the same with minor changes of course. 3.1L is part of *60 degree family
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wait a sec did I see 3.1L TBI and Camaro, thats not right, it should be same MPFI

 

You can swap all your mpfi components over to the 3.1 block.

 

Well, the motor started its life in a 1992 Camaro, was pulled for use in a performance S10 truck project, completely rebuilt, bored up, with new pistons, high compression, valve job, polishing, cranking out 175hp. maybe that's when the change was made?

Anyway, I thought Camaros were TBI from 1990 onwards...

Either way, thanks for clarifying things for me.

Just put it in, bolt on the old intake manifold and it will purr, without having to change anything else? That makes me really happy

I'm guessing, though, that my manifold won't let this motor spread its wings to its full potential, but heck, it's a good start.

We're something of a Camaro family, my sister-in-law has a 1981 Z28 convertible (pretty rare). It seems this upgraded 3.1 should give me about the same horsepower. On a lighter car. I'm absolutely hyper about this

Once again, thank you!

 

The 3.1 is good for a few more horses. The S10s are TBI but your maniflold will bolt up.

 

3.1 is dist less ? big hole where the dizzy is?

 

3.1 has a distributor.

 

Everything from the intake manifold up gets swapped over. EVERYTHING. You will need to log onto eBay and snag yourself a set of injectors for your 3.1 (just got myself a set for $30 last night) and swap those over to your 2.8 fuel rail. Keep the same ECM/PROM combination, just swap the injectors, including the 7th cold start injector, if you have one. Swap over your exhaust manifolds (and AIR system if your car has it), brackets, power steering pump, A/C compressor. It will probably be a good idea to clean the crap out of everything while you are doing the swap, and to replace the rear main and timing cover seals, timing chain, etc.

Few notes:
1. The 3.1 is internally balanced. Your 2.8 MAY have been, not sure when the changeover happened. You MAY end up getting the proper flywheel/flexplate for your 3.1, if it doesn't have what you need already. If you need a flexplate, I have my old one sitting in the garage (from when I did my auto/manual swap, yes, it's for my 3.1).
2. You might need to snag the fan switch out of the back of the 2.8's pass side head and swap that to your 3.1, knock the plug out of the back of your 3.1 head and put it where it is supposed to be. Also, you might need to swap over the temp gauge sender that is in this same position on the other head (same corner, opposite side, so its in the front).
3. I can't stress this enough: Unless you KNOW the donor vehicle has been driven within the past few weeks and the coolant was freshly drained, REPLACE THE WATER PUMP. If you don't, you could end up with a failed one within a few weeks and end up replacing it anyways (like happened to me after my swap), and it's just plain easier to do with the engine out.

:edit: BTW, for doing this, you get 5 HP and 20 Tq (with base engine, you will obviously get more with the modded internals).