Hi all, 90 commanche

hello everybody!.
New to this forum. Lots of good info so far. I have a 90 Comanche, 4.0 5 speed, 2wd. From what I can find, it looks like it has the AX15 tranny. Total mileage is ~ 181,000 miles. Still runs good, needs a little work.
I am thinking of doing a v-8 swap. I don't have any fabrication facilities or abilities. Good with electrical though. Are there any good threads or sites that would shed the light?
I want the easiest way out. Small block chevy with the original trans. Possibly the 5.0 Ford and t-5. Would prefer to keep it manual.
The window sticker says 3.73 rearend. I changed the fluid and did the math of the stampings on the pinion and came up with 3.07/8. If I can keep the overdrive, I think some 3.55 would be perfect.
Goals- Reliable daily driver, torquey-not high winding, good mileage- presently at 22-24 hiway.
Concerns- Exhaust- what manifold or header, power steering hoses- looks like a saginaw power steer pump, hydraulic lines for clutch, tranny- already has a poor 1-2 shift after doing Beartooth highway pass loaded down.
5.0 TPI 5 speed from a Camaro or Mustang would be great, which is the easiest?
Thanks, MikeB

As a fellow Comanche person you would be better off keeping the 4.0L...the V-8 swap is way to overrated and needs way more effort than its worth...

your rear gearing is going to be 3.07's with a 4.0 5spd...as far as gearing goes do you plan on putting bigger/smaller tires or what...if you putting different tires on 3.55's would be ok but getting 24MPG is going to be tough to atain but its possilbe...

My best tank so far is 25MPG with a 4.0L 5spd 4wd 33's and 4.10's

4.7L stroker. Better than a stock V8 in both torque and HP, and you would have effectively a new motor, for what you would pay for a used V8 and trans. And you can make one and get it running for less than 2k.

for those that just got pissed off when I said that the stroker is better than a stock V8, remember that 305s and 350 sbc's were not very strong from the factory, b/t 200-250hp. And the fords are even worse, the 5.0 is less than the 305sbc, and the 4.6 is not much better. That is a lot of coin for a motorswap that gives you stock power for twice the price of a stroker build.

WMBigs said:

hello everybody!.
New to this forum. Lots of good info so far. I have a 90 Comanche, 4.0 5 speed, 2wd. From what I can find, it looks like it has the AX15 tranny. Total mileage is ~ 181,000 miles. Still runs good, needs a little work.
I am thinking of doing a v-8 swap. I don't have any fabrication facilities or abilities. Good with electrical though. Are there any good threads or sites that would shed the light?
I want the easiest way out. Small block chevy with the original trans. Possibly the 5.0 Ford and t-5. Would prefer to keep it manual.
The window sticker says 3.73 rearend. I changed the fluid and did the math of the stampings on the pinion and came up with 3.07/8. If I can keep the overdrive, I think some 3.55 would be perfect.
Goals- Reliable daily driver, torquey-not high winding, good mileage- presently at 22-24 hiway.
Concerns- Exhaust- what manifold or header, power steering hoses- looks like a saginaw power steer pump, hydraulic lines for clutch, tranny- already has a poor 1-2 shift after doing Beartooth highway pass loaded down.
5.0 TPI 5 speed from a Camaro or Mustang would be great, which is the easiest?
Thanks, MikeB

Click to expand...

The 1990 should be the AX-15 - IIRC, they went to that from the wretched Peugeot in mid-1988 (August or so. Or was it 1989? Aw, Hell - I got my first AX-15 from a 1990 donor anyhow...) The AX-15 is a decent box, and far better than the BA-10/5 it replaced.

3.73 gearing would probably be found with the 4-cyl, while the I6 with the manual got 3.07 almost universally. However, the I6 with manual would be better complimented by 4.10 or so gearing (I'd have to crunch the numbers again, but I'm thinking that it was 4.10/4.27 or so for better gearing and torque response.) The AW4 was actually well-matched with the 3.55 gearing it got from the factory, I'm not sure what AMC was thinking when they spec'd 3.07 for the manual. If you can find a four-cylinder XJ, chances are good it will have 3.73 or 4.10 gearing underneath it, and the rear axle will be a drop-in proposition (conversion to 4WD would take some more work. You'll have to find a 4WD transmission, get the transfer case as well, matching front & rear axles, driveshafts, ...)

I would tend to agree with opinions previously stated - stick to the 4.0L, and possibly go with the "low-buck" stroker (258ci crank, no overbore - you will still see 275ci, and an increase in torque output. Better low-end that most V8 engines, also...) and you won't have to do any fabrication to make the thing work - just build the stroker and swap injectors (you'll need more fuel delivery.) Gear the axle a bit lower to complement the setup (3.73 would be a minimum, y'ask me. If you cross the carrier break, throw in an LSD as well, and go with 4.10 or 4.27 gears from the off - you'd want to regear for the V8 swap anyhow.) And, I don't think the AX-15 would mate to any V8 save possibly the Chrysler LA-block - with a Dakota 3.9L V6 bellhousing (derived from the LA-block V8,) so you'd end up having to fab engine mounts, transmission mount, and probably adjust the transmission tunnel - do you want that headache? I didn't think so...

The stroker is going to be the easiest way out for you, I think. Or, let me know where I can pick up my new truck - I could really use a light pickup, and it would help if I could get one where I already know what colour the wires are...:laugh3:

Thanks for the info all. I am checking out the 4.0 options.