[jimmykicker]

so, the 3.1 would be 89mm x 84mm

there are a lot of 3.4 engines out there, but i’m not sure if any of the RWD versions were TBI. I think in the Camaro/Firebird they were maybe MFI at that point? Just saying be sure to get the ECU and harness from the donor vehicle.

Another thing to think about… I don’t know the rules in your state (TX?), but in GA cars over 25 years old don’t need emissions inspections. That means that you might be able to find a ‘95 or ‘96 3.4 with OBD-II, which would possibly let you tune it. I don’t know if they ever made a 3.4 RWD with OBD-II, but could be worth researching…

Let us know if you find anything!

You are correct. There is no such thing as a 3.4 TBI engine. The Camaro had the SFI engine in 94. My truck is an 84 and I converted it to TBI EFI. To accomplish this and it not be gutless, I had to use a 4.3 TBI unit from a Astro van, bore out a stock TBI intake. I rebuilt the injectors, and it runs pretty well. However, you will need to do some turning because there isn't any "drop in" tune for this configuration since it was never offered. It spark knocks like crazy on regular fuel, so to me that indicates at least how important that is. However, I never tried to tune mine and just run premium. These days with all the stupidity going on in our federal government and gas prices so high, I'm considering educating myself on it. If it was my DD, I'd certainly have already done that. I probably haven't put 10k on that engine in 12 years. It's an ex food delivery truck I pounded on for 12 years that I kept out of the junkyard by replacing everything on it back in 2010. It's retired now and just for fun.

 

[riscy]

Yah - the tuning aspect is what’s so difficult. The number of places able/willing to tune those OBD-I systems has dwindled. When you do find someone who can do it, I was repeatedly told they won’t “waste their time” on something that isn’t a V8/common engine. Doesn’t mean there isn’t a way to tune that stock ECM, it was just very difficult when I tried it.

That’s why I was bringing up the ‘95/‘96 (‘97?) engines - they would (possibly) be OBD-II AND out of the emissions requirements in most states - and tunable via software. Or get a MegaSquirt for the modded 2.8.

 

[jimmykicker]

Yah - the tuning aspect is what’s so difficult. The number of places able/willing to tune those OBD-I systems has dwindled. When you do find someone who can do it, I was repeatedly told they won’t “waste their time” on something that isn’t a V8/common engine. Doesn’t mean there isn’t a way to tune that stock ECM, it was just very difficult when I tried it.

That’s why I was bringing up the ‘95/‘96 (‘97?) engines - they would (possibly) be OBD-II AND out of the emissions requirements in most states - and tunable via software. Or get a MegaSquirt for the modded 2.8.

There used to be a bunch of guys on here that had done this same thing I have done, but they are all gone to my knowledge. They could burn us a chip that's "in the ballpark" of what we needed since they had tuned their trucks with a custom tune, which for me would be fine. Currently my truck is running a 4.3 chip. It runs ok on it, but like I said it requires premium fuel which is annoying. And expensive. I know it could do better on fuel too. The SFI conversion is more attractive to me right now at this point due to tuneability and support. Not sure all what that entails though.

Maybe Raven can expand on that?

 

[riscy]

Yah, you can buy the proms and tuners, but it’s getting that “baseline” tune and being able to massage it that’s difficult these days.

SFI is intriguing. I had looked at a 3.4 intake and injector setup, but was too chicken to see if I could make one mate up to the 2.8. Again, though, you’d still be OBD-I and up a creek regarding a tune. You’d need to go with a…

O. M. G.

I just realized you could use a Holley Terminator X on a stock 3.4 intake on the 2.8 and have the best of all worlds. Even TC lockup control. Damn - wish I had thought that through sooner!!! 🤣

 

[manbearpig]

I wouldn't bother trying to make the 3.4l stuff fit a 2.8l, just use the whole engine... If you're going to Frankenstein, you might as well go into the hybrid world. The 60 degree V6 didn't get interesting until they started putting aluminum heads on it. wot-tech.com has tons of performance parts for them too.

 

[riscy]

I don’t disagree. But the original premise what what could be done with a 2.8 and we’ve been riffing ever since

 

[DougE]

The original thought was to take a relatively rust free 1st generation S10 without an engine and transmission, and put in the left-over parts from a V8 swap to make it into an inexpensive, reliable driver.
A compression test proved that the 2.8L would need a rebuild but it would be reasonable to upgrade to the 3.4L. As of now it appears that the most economical course would be to source a 3.4L short block, move all the 2.8L parts over to it and use a Weber carb.
If you upgrade to the entire 3.4L system, you face dealing with modifying the computer to work in this application and an upgrade to the fuel pump. While the engine connections are fairly easy to adopt, there is no information (i.e. a wiring diagram) to define the necessary computer harness modifications. (If you go to the next level and get a 4.3L then a replacement transmission would also be required.)

 

[manbearpig]

I would just hook the computer up like it came from the factory. Buy a Camaro service manual and it should be cake. Use a manual transmission and it's even easier, not to mention actually feel like it has some power, rather than have it all sucked dry by the autotragic. Use a plastic fuel tank/pump from a flex fuel S10 and you'll have way more capacity than you'll ever need.

 

[DougE]

I have located a 3.4L engine in the area. It is not in the vehicle. How can I verify this is the engine I am looking for?

 

[jimmykicker]

I have located a 3.4L engine in the area. It is not in the vehicle. How can I verify this is the engine I am looking for? View attachment 371366
View attachment 371365 View attachment 371367

that looks like a FWD 3.4. Not what you’d need. The direct swap motor is a 3.4 from a 93-95 Camaro/Firebird. Pretty much that’s it. Unless you can find a crate motor (basically impossible.). Jegs in the past has sold complete 3.4 long blocks which I think is a smart idea.

 

[DougE]

Thanks for the response. It pays to do due diligence, doesn't it? I can see that the exhaust routing is appropriate for what you are telling me. (Am looking for the identifying marks on the engine I will need to be sure in the future).

 

[Ed Mc]

Doug, the F-Body block ('93-'95 Camaro/Firebird) has a large "F" cast into each side of the block (see attached pics). Also has a lot of stiffeners cast in which decrease NVH over the 2.8 block.

BTW just an FYI, you can buy an adapter that bolts to a 2.8 TBI intake and allows you to use a Holley 350/500 2-bbl, or early Autolite carb. A much cleaner solution than trying to source some "Unobtanium" aftermarket intake or using an older S10 2.8 2-bbl that breathes poorly. Here's one such adapter being sold on eBay:

2 barrel 4412 HOLLEY 500, 350, TO CHEVY TBI manifold adapter 44mm 1.75 USA | eBay

Find many great new & used options and get the best deals for 2 barrel 4412 HOLLEY 500, 350, TO CHEVY TBI manifold adapter 44mm 1.75 USA at the best online prices at eBay! Free shipping for many products!

www.ebay.com

This seller has sold a Grunch of 'em so I'd expect they're putting out a good product.

I have a '90 Trooper that used to have a GM 2.8 in it. Did a 3.4 Camaro swap 20 years ago. I did not have to upgrade the fuel pump, or change the ECM. I did have a Holley Big-Bore TBI that used to be on another 2.8 Trooper I owned, and that was transferred over the the 3.4. It also has 1.6:1 roller-tipped rocker arms, improved air intake, bored-out intake manifold (to fit the Holley), and a free-flowing 2-1/2" exhaust.

The TBI system adapts to the bigger engine fairly well except that a 3.4 with stock 2.8 TBI will lean-surge on cold starts, because the fuel map isn't enough to feed the engine in Open Loop. After the engine is warm enough for the ECM to run in Closed Loop, it'll run fairly well, but you're losing a lot of performance via not enough airflow out of the small TBI. You can raise fuel pressure and that'll help but the real answer is using a 4.3 TBI and boring the intake manifold to 1-11/16" to match the bore size of the larger throttle body unit.

You can do some fine-tuning of this setup by installing an adjustable regulator. Or sometimes all you need is to install a 14-psi spring in the stock fuel pressure regulator.

The Trooper runs great, and the hopped-up 3.4 hauls its 3800-lb carcass around pretty well!

IDK which way you're gonna go carb or EFI, but I know you'll be happy with the performance of a 3.4 vs 2.8.

One last thought, to simplify things you could run a Holley Sniper TBI setup. Not necessarily the cheapest way to do it but they work very well. IIRC Holley has a smaller 2-bbl unit that, with the Carb-to-TBI-Intake adapter, should work. At least one Trooper Dude at the Planet has done that mod and reported excellent results.

HTH..............ed

 

[DougE]

That is certainly good information, Ed Mc, I appreciate the effort. (I've put a FiTech unit on a jeep but kind of want to stick with a carb on this guy.)

 

[jimmykicker]

Doug, the F-Body block ('93-'95 Camaro/Firebird) has a large "F" cast into each side of the block (see attached pics). Also has a lot of stiffeners cast in which decrease NVH over the 2.8 block.

BTW just an FYI, you can buy an adapter that bolts to a 2.8 TBI intake and allows you to use a Holley 350/500 2-bbl, or early Autolite carb. A much cleaner solution than trying to source some "Unobtanium" aftermarket intake or using an older S10 2.8 2-bbl that breathes poorly. Here's one such adapter being sold on eBay:

[

The Edelbrock is still available. Jegs has them. Not cheap though. $550 for the base and 4bbl top! Yikes. I think I paid that for the carb and intake in 2005. Offenhauser had one too, but talk about unobtainium! I think @Mad Max has one. I've never actually seen one in the wild.

Definitely agree though to not use a stock 2.8 carb intake.

 

[PeteD]

The Edelbrock is still available. Jegs has them. Not cheap though. $550 for the base and 4bbl top! Yikes. I think I paid that for the carb and intake in 2005. Offenhauser had one too, but talk about unobtainium! I think @Mad Max has one. I've never actually seen one in the wild.

Definitely agree though to not use a stock 2.8 carb intake.

No matter what , this will be an interesting venture that's bound to grow the budget.

 

[jimmykicker]

No matter what , this will be an interesting venture that's bound to grow the budget.

I think if you put a v8 in a truck like this, most people would figure it would run like a beast. I think more people would be surprised if it ran like a beast, and had a rather stock looking motor in it.

 

[PeteD]

I think if you put a v8 in a truck like this, most people would figure it would run like a beast. I think more people would be surprised if it ran like a beast, and had a rather stock looking motor in it.

Tru That. More so if budget unlimited.