Ok, please don't light me up like Cape Canaveral with flames, I'm no mechanic, but I am considering a project, namely an engine swap into an early Pontiac 3rd Gen. I did read the sticky about swaps, but it's a bit incomplete.

I know this question involves more detail than can be covered in a few posts, but I'll ask anyway...has anyone replaced the old 305 in an '82-'84 with a L98 setup from an '85-'92 (or '85-'91 Vette)?

If so, how hard is this? I'm looking to start this long term project late next year and have narrowed it down to a '82 Recaro or an '84 T/A. I have lots of ideas, but the first would be installing a L98 TPI system because they're cheap, lots of torque, plenty of engines and simplicity of the design.

I know all about the LSX conversions that are the rage, but I'm not building a street racer, just want a nice clean early 3rd Gen with more poke than the stock mill and don't want to break the bank.

If you've done a step-by-step of this swap already, I'd like to see your thread, just point me that way.

Any insights would be welcome!
Thanks for your patience with the new guy!

 

Okay, '82-'84. Assume V8. If so, your engine possibilities are Crossfire (dual TBI's) or q-jet.

Crossfire - I wouldn't bother with the system. Doesn't mean it can't be made to run better, but it is extremely limited.

Q-jet - I maintain you can't find a better street/performance carburetor than the factory computer q-jet. Pull the 305, put a 350 under it, put decent exhaust on it, great performance. Some details to be discussed, but basically do the "usual" hot rod stuff to it, it'll be fast.

Now, if you really meant the entire L98 engine/system, with TPI, it's basically a matter of installing the engine, installing the harness and computer along with sensors, provide proper fuel pressure (the factory did it with an in-tank electric pump with switches/relays to go with it), little things like throttle cables & radiator hoses, you're on the road. BUT, all other things being equal, the q-jet would make more power than the TPI.

 

I had heard that about the Quadrajet, but I guess part of the reason I like the TPI is the benefits of fuel injection and economy (not that a 5.7L is exactly a Prius or anything...). I like the factory look and feel of the TPI (as limited as it's breathing was, stock), and it's a good starting point once its in to juice up later. I've driven a lot of L98's and like thier low end grunt and highway pull.
Like any project, I guess its a matter of 'like' as much as anything...hot rod projects seldom survive the cross examination of extreme logic! LOL! I once had a HPP magazine with an article on a guy that crammed a 455 into a Fiero, so who knows how these ideas start!
Anyway, I guess if I find a decent donor car with the 5.7L setup, all the parts are going to be there. My concern is tripping over not knowing what small parts I might need and what I might over look. As old as the L98 is, do you know of any step by step web or magazine articles that might cover such a swap?
Thanks again for your input, it is appreciated!

 

Try over on http://www.austinthirdgen.org/. Maybe somebody local has what you need?

 

Opinions are worth just what you pay for them, but you couldn't pay me to go back to TPI. I had one on a 305, and I've driven both of my parent's 4th Gen L98 vettes (all nice, low miles, and very well tuned cars mind you). That being said, I've yet to drive a properly tuned quadrajet that didn't have all the torque of TPI at low end, plus a whole heck of a lot more punch at higher RPMs. Now, I've never messed with a computer controlled quadrajet, my stuff all runs the old style non-CC quadrajet with a standard mechanical/vacuum advance HEI distributor. The 305 in my Formula modified as such was a beast compared to my old 305 TPI Trans Am with the same mods (headers, complete exhaust, etc.) It had all the low-end grunt, plus the ability to breathe at higher RPM, even without the TPI cam.

And that was before all the modifications to the 305 I did. It now has L98 Aluminum heads, a CompCams XR258 cam, 1.6:1 Harland Sharp roller rockers, a Weiand intake, and some other goodies. All that change, and the only thing I had to do to the carb was richen up the idle just a hair. That much change would have been rough for a TPI to handle.

To make a long story short, in case you couldn't tell, I'm a strong proponent of the quadrajet carb. Take the time to set one up right, and you won't regret it. Plus, it's a whole lot easier and cheaper than dealing with that fuel injection mess. If you want some motivation, scroll down about halfway through my build thread link below. It details some of my engine build, I think you might like what you see.

-Levi

https://www.thirdgen.org/forums/memb...engineers.html

 

I've run a bunch of q-jets over the years, and by far the computer q-jets were the best of the bunch.

That being said, I don't fault you for wanting EFI. The only carbs I have now are either in the garage attic or in the storage unit.