4.3L vortec swap

[The-Hurricane]

my jeep has the 3500?? transmission i think. if i need an entire donor truck would a 97 gmc jimmy with a 4.3 vortec work?? theres one sitting in my garage right now. why would my current rad not work? its brand new and when i ordered it the same part number came for the 2.5 or 4L.

i looked at carbed 350 swap, the jeep place here can do it for 1000 cnd plus motor. but then im running a honkin big 5.7 and im not sure i want all that? the 97 jimmy with an auto in my garage gets around 450k to the tank (60L) and it weighs twice as much as my tj and has an auto trany. i think i would get unreal fuel mileage and more than enough power to spin my 31's. i dont really plan on upping my lift or tire size ever. i want to get an old yj and put 2 ton diffs and 44's on it down the road once i have my own shop. right now i just want a good reliable dd that doesnt chug up a slight rise.

[Double AA]

As long as the GMC is complete, it would be fine for a donor. Compare the GMC's radiator with your four banger's and if it has comparable surface area, capacity and the inlet and outlet are close it should work.

I put an LS motor in my CJ, and while it's fuel mileage is far from unreal, it's much better than the injected I6 it replaced. In fact, during a three day wheeling trip, and my CJ with one ton axles, trany and 37's got much better mileage then the 4.0's and four cylinder TJ's did. The TJ's were on 32's and 35's with stock sized axles and transmissions.

[The-Hurricane]

see im not worried about 4wheelin mileage, cause fun is fun regardless of the fuel. but what worries me is that its my daily driver and i want if not great then no worse than what it is now

[inVERt'D]

So you've got a CJ-7 with a 4.3 and another CJ with an LS? How you like that NV4500? I'm fixin ta put one in my rig.

x2 on everything DoubleAA said; you may even need to swap your fuel pump if your Jeep pump won't put out enough volume or pressure.

I don't believe they ever used the NV3550 behind the 4-banger, but I could be mistaken. Check your numbers and find out what you have, cuz an AX-5 ain't strong.

I think the 4.3 would be a great engine for your Jeep. I've driven some little Blazers on and offroad with it, and I was impressed--that is one peppy V-6.

[Double AA]

No V6, just one V8, but the installation is nearly the same. I know a few guy's with the 4.3 and they worked out great.

If you already have one, then you know the NV4500 is short, but big heavy transmission. And if you want to have a flat skid you'll need to cut a large hole out of your floor.

They're built hell for stout, but being a truck transmission it's not the fastest shifting tranny out there, not bad, but it ain't no Muncie. It does shift better than the T18 I had. And like most granny transmissions there are some wide gear spreads. Not huge gaps, but not the tranny for stop light to stop light races. It's kind of like a three speed trans with a granny and overdrive. The earlier years were wider.

The unit I have is a hybrid. The front section is a GM with the 6.34 first. The rear is a Dodge with the closer ratio's and a synchronized reverse.

For rock crawling and general off roading it's a great transmission and you'll never have to worry about it breaking - ever. Run whatever horsepower, axles and tires you like, you'll have enough tranny. But for a daily driver that occasionally see's Big Bear and the like, there's better choices.

[inVERt'D]

Not trying to hijack this thread--honest, this is relevant to Hurricane's engine swapping! How hard and expensive was it to get that 6.34 granny in there?

Mine's a 1998 Dodge unit with the 5.61 or whatever; not bad, but could be better for a granny. I was toying with the idea of 4-spd like the SM465, but I could use the overdrive and like the synchronized granny and reverse.

By the way, here's a post that shows resources for all kinds of engine/ tranny swaps. Of course there are the usuals, like Novak and Advance Adapters.

http://www.jeeps-offroad.com/f41/eng...housings-4740/

[The-Hurricane]

thanks for all the links and the info guys, its really helping me figure out whats on my to do list! i decided on the motor swap the other day, i was thinking to myself, why spend a grand on exhaust and a chip and everything for my 2.5L when i still wont be happy at the end of the day. so its time to save up my pennies and gather me some parts!

[Double AA]

How hard and expensive was it to get that 6.34 granny in there?

I bought the transmission several years ago from a company that specialized in this conversion. The problem is the 6.34 is from a pre 1994 GM transmission, and they're real scarce now. You would have to buy two new shaft/gear assemblies from GM, which probably wouldn't make sense.

I'm sure you'll be happy with a 5.61 first gear and a 4/1 transfer case.

[inVERt'D]

Double AA,
Yeah, I'd drop in an old 4-speed before I did that. Some of those old boxes had 7:1 or slightly lower. BTW, those pre-'94 gm 4500s aren't scarce--they're all in Jeeps and whatnot!

I'm sure you'll be happy with a 5.61 first gear and a 4/1 transfer case.

Heck, right now I'd be happy with a 4.01:1 first gear and my 2.73:1 transfer case, if only I had a first gear.

Hurricane,
You're not supposed to be happy at the end of the day. It's a Jeep--you're supposed to continually upgrade it until you die a penniless old man, full of regret over a life spent looking up at the bottom of your rig. Anyway, if you need any more advice, opinionated remarks, off-topic diversions, or just some encouragement, you know where to go. :wink:

[The-Hurricane]

i know i want ever be finished! it just makes me feel good inside when i finish a upgrade and say ok thats good enough....then i go on mjr and start looking for the next thing....

and i really apreciate(sp?) the info and the off topic diversions!