I've gone back and forth a bunch on what I want to do with my LG4. I had originally intended to LS swap and then I was leaning towards a L98 swap to keep it period correct but now I kinda just want to put a 5.7 in it and reuse all of my stock components, if possible.

So, assuming that I'm going that route, am I looking at any pre 1996 350 for all of my stock accessories, intake and exhaust manifolds to bolt up? Seems like most of the new crate engines available use vortec style heads so my stock intake won't work.

 

If you are wanting to do something that is mostly stock appearing and is period correct appearing, I'd try to build something in the spirt of the Chevy Race Shop ZZ3/ZZ4 350 H.0. Camaro engine conversion kit for 1982 to 1987 LG4 automatic and 1984 L69 automatic Camaros.

A much better intake manifold can be used than your factory GM intake while still being stock appearing.

None of your stock LG4 exhaust system can be retained. It sucks so bad there would be no reason at all to do anything else if it had to be retained.

 

This is what it would look like under the hood.


As installed in a 1987 Camaro

 

SBC 400, SFR 195's, cam of your choice, best dual plane you can fit under the hood, paint all of that aluminum satin black, use stock tin valve covers and air cleaner. Put all accessories and emissions stuff where it belongs (functioning or not), and go burn some rubber!

Any "Not-Vortec heads", all your stuff will bolt up.
Stock exhaust manifolds will murder the power potential of any engine. I'd recommend making the appearance "concession" of using headers and header back exhaust.

 

Exactly what I did with my build. Only difference is mine is a Canadian LG4 (no computer/AIR etc.)
Just EGR, Charcoal Canister, Cat. etc.
I eliminated the EFE because of my shorty Hedman headers.

 

Some of the ideal parts aren't available.

Parts I have owned / used.
ZZ3/4 intake - best 86-down EGR spreadbore intake for legality and slight improvement over stock.
Slot the middle holes and use angle washers for 87-up heads.

The 88-93 serpentine accessories bolt to centerbolt heads. No reason not to use them. Try the TBI support brackets or fab some for triangulation.

A max effort Vortec build goes to LS levels of cost. But if I were going that route, GM had the 3.8" crank for 1pc RMS blocks in the HT383.

Figure out how fast you wanna go. If one of mine hadn't been stolen, I might still have a smogged Qjet sbc registered.

 

What are your goals with any engine work/swap?? Do want a quick car or a effing bat out of hell fast car? Others like Sofa have stated the LG4 cars have a crappy exhaust system (manifold to tailpipe), a tiny cam shaft and you probably have a rear axle ratio of 2.73 if it’s an automatic.

Swapping in any roller cam block 350 with any aftermarket iron heads can give you the OE look and a lot more power depending on your budget and desire. I would not use any of the exhaust from the OE setup as that would be negating most of any power you gain.

Maybe state you goals, desires and budget for some more pointed suggestions from the more knowledgeable people here…..
..

 

When I made this thread, my main goal is a budget friendly, reliable cruiser that will get out of its own way when I hit the gas. The LG4 now is pretty darn slow.

I do have a 2.73 non posi rear in the car now. That will definitely be swapped out along with exhaust no matter what I end up doing.

The more I've thought about it and researched, I think I will end up regretting anything other than an LS swap. The only other swap that interests me is a L98 swap, just to be period correct for nostalgia. It would be cheaper than an LS and would be a big performance improvement over what I have now. I just think that after a while, I'll crave more and will want to do the LS swap so I might as well start now.

 

My stock-ish rebuilt L98 TBI build.