I was looking at the GMC Syclones of this year model and was wondering how hard a v6 Sonoma, or even the 4cyl model with an automatic tranny would be to convert to a LS1 4L80E tranny setup would be. Or would a carb or EFI base 350 be a better idea with a TH350 tranny? Possibly even a 383 stroker motor? Anyone done one of these? This could possibly be my next project!

 

I know Lingenfelter did a newer model w/ AWD and a twin turbo 427...

I do believe there is a guy that browses around here with a S-truck with a ls1 in it, and i'm pretty sure there is a SBC one around here too.

I'd go with the LSx swap, the 80e might require a tad of BFH on the tranny hump, but I wouldnt imagine it being too much.

 

I have an uncle with a tranny performance shop so getting the tranny work figured out will be no problem. I just didn't know how hard swapping a 350 into it, or LSx into it would be (i.e. motor mounts, wiring harness, etc.). Or if the engine compartment of one would have enough room.

 

Definatly enough room. for a SBC they actually sell kits on summit/jegs.

the 4.3l v6 that was in those models, is (for the most part) a SBC 350, with the front 2 cylinders wacked off....

You will have to run a different radiator and motormounts.

I wish i still had my old bookmarks, I'd post a ton of information for you, but alas, I lost them. Google a little aswell, and I will to.. If you do come across something semi interesting, post up, I'd like to see it.

 

try turbols6.com THANKS

 

Yeah, try TurboLS6.com. Tydriver (his screename on here & the SyTy.org board) is swapping an LS6 (soon to be turbo'd) into a Typhoon.

The biggest determining factor in the difficulty level of the swap is: 2wd or 4wd / awd?

2wd is fairly straightforward, engine mounts & headers are available. Minor frame modifications required (Ok, you might consider them major, but its just a couple of notches). There is a manual available for it (in electronic format). Check with v8S10s.com, I think its like $18.

4WD / AWD is a whole different ballgame. Engine mounts are about to be available, but header choices are virtually non-existent. Major oilpan mods are required. Basically, there isn't a "kit" out for this application yet. There are some folks working on it (Tydriver above) but its not there yet.

With either choice, you really need to run the Corvette accessory drive package. The truck package is too long, the F-body package puts the alternator and the steering box in the same place (which doesn't work). Other alternative is to make your own bracket to mount the alternator up high with the F-body package.

Harness stuff is probably the most scary (or at least intimidating). I'd check with Speartech & currentperformance.com (they've got some useful info as to how easy/hard the swap is.) I think Speartech is a better choice, their reputation for quality work at reasonable $$$ is untouchable. But the currentperformance site does have some good info.


The smallblock is a much easier swap, especially if you're starting with a 4.3l. The accessories bolt up, all the parts are available (and cheaper), many choices in headers. But your EFI choices are much more limited (and expensive). A LT1 / LT4 would work, but the accessories don't (LT1's have that cam gear driven water pump & front mounted distributor). Best EFI solution (if thats is what you want / need for emissions compliance) would probably be an aftermarket system or an LT1 / 4 manifold converted to work on a standard SBC (needs crossovers / thermostat housing & drill for distributor). Or run a carb (if you don't have to pass emissions)

Both engine familys can make power. Personally, I think the LSx is a better starting point (stronger bottom end, better heads), but its a significantly harder fit into the chassis. Ultimately its your call.

I'm still in the planning phase of a LSx swap into a 1998-2000 4dr 4wd Blazer (or Jimmy or Bravada). Basically, I want to build a 2nd gen 4door Tyhpoon. Hopefully sometime soon I'll move into the acquisition phase.

'Dreamin'

 

Dreamin, You said everything I wanted to. Great info on this site, and there are a few s-series trucks doing and that are done with the swap. I sure all of them will be happy to answer any questions you have.

SSLOWERED

 

Well, I just looked at some sites with Crate motors and it looks (pricing wise) like the best setup is a 350 carb motor. About $2,000 for a block, cam, and heads witha round 290hp. If you were to stroke it out to a 383 and put a few bolt-ons with it that'd be awesome... I do live in an emissions area, so how hard would it be to drop in a carbeurated motor and still pass? Thanks again for all the info.

(Oh, and it is a 4.3L auto truck... and I really want to leave it auto)

 

Leaving it auto isn't a problem.

However, depending upon your area, passing an emissions test with a carb will range from difficult to not possible.

For example: California. Not possible. They have a visual inspection, and you'd never pass it to even get to the emissions part of the test with a carb.

Maryland (my home state): Possible, but very difficult. A 1990 to 1993 vehicle has to pass the IM240 Dynamometer Treadmill test. What this does is test the emissions under load, simulating driving down the road. You have to have your carb absolutely dialed in (dead on) in order to make it pass. Because rich spots and lean spots will make you have too much HC and too much NOx emissions (respectively) and they're looking at both. There is no visual, so they don't really care what's under the hood, but you've still got to pass the tailpipe sniffer, which is the tough part.


My recommendation: Check out your local emissions regulations. Figure out what you can get by with and can't get away with, and plan accordingly. I'd suggest you forget about running a carb AND passing emissions.

'Dreamin'

 

where are you from?
i have a 355 tbi in my 1993 sonoma and kept the 4l60e. runs 12's, 20 mpg, and passes the tailpipe test!

it is a great daily driver.

ps - the a/c still works too.

 

You could always do this (scroll down) and register it as "the model/year it appears to be." That is the law in Oregon, so my 99 C5 will register as a '61 C10

Good Luck (and go with LSx)