zraffz

I just joined the forums, this is an idea I'm throwing around and not definite! I have a 91 Jeep Cherokee, lifted 6.5" and it runs fine.

I also own a 454 bored .040 with ported/de-burred peanut ports and a mild cam. (we figure it put down about 400 FWHP/500+ TQ) Well it blew a skirt apart on piston #7 and nicked the cylinder wall. Now I'm going .060 over, clearancing an extra 1/4" and running the same heads with a slightly more aggressive cam... shooting for just about 420 horse and bumping the torque to 550+.

I know the obvious such as trans, transfer case and eventually front axle (already has a Ford 8.8 rear) but what kind of work am I looking at to make this big block fit into the Cherokee?

I have yet to measure anything, I'm descent at fabricating and imagine the firewall has to get cut out and rebuilt after the motor & trans are bolted in place.


Anybody have any pictures/tips/advice on this; I'm not much of a Jeep guy.

rweaver138

your going to want to plate/reinforce the entire unibody for sure

will a big block even fit?

zraffz

I've yet to measure, I doubt it will fit without at least pushing the firewall back. (I had to notch and redesign the firewall in my camaro to fit it).

I forgot to mention the unibody, I'd defiantly strengthen it. I'd probably run square tubing from front to rear over top of the original unibody rails and tie it together left to right by the front and rear bumpers.

N20jeep

Try prostreetjeep.com he's running a 454 in his xj and I'm sure hell cover some stuff I missed.


Firewall shouldn't be a problem, just maybe some trans tunnel reshaping. But header-go-header clearence may be a problem. Hood clearence will also need to be addresed with some sort of cowl hood.

The torque from the big block is going to give hell to the unibody, so I'd plate the frame rails at a minimum.

And cooling will be an issue, so figuring out a cooling system that will fit and cool will take some thinking

zraffz

thanks man for the link. I'm not concerned about unibody strength, it will be addressed after the motor is in place. I am going to probably only run a 700R4 (1/2 ton trans which is small and should fit in the trans tunnel)
Hood clearance will be a later worry as well. Cooling I have covered (maybe), I have a 3 core radiator from my camaro that kept the motor cool and since I doubt a clutch fan will fit anymore I'll run my two aftermarket electric fans.

I thought a little bit about exhaust already, probably will just run a set of manifolds off a car and rework the frame rails where they interfere.

If I can get away with just beating the firewall back instead of having to notch and redesign it, I will defiantly go with the big block.

sheepdog

lol you NEED to make a build thread for this lol as well as many many pictures, possibly even videos lol i have a friend that has a cherokee with a chevy 350 runnin 340 horse, but a 454 is just awesome.

zraffz

Well I gotta finish rebuilding the motor. It used to be a 468 but now its becoming a 496. We should realistically gain 50+ ft lbs (550) and with the right cam I can see close to 440-450 horse. I'd safely say this motor can put my big lifted cherokee into the 13's and still out perform off road.

I'll get pics of the jeep up tomorrow, this project won't happen for a few months though... like I said I need to still dump another grand into the motor to have it machined again. Maybe I'll sell my Z71 and fund some bush whackers, my windshield, machine work, and trans and transfer case.

Metmknice

I would say sell it, and put an LSx motor in it.

zraffz

It would be too expensive to buy/build an LSx. An LQ4 can be bought and built to make comparible HP for about 2 grand but I'd lose too much torque. Not to mention I don't want to deal with a wiring nightmare.

jcwclm

Run the exhaust through the hood like this!

http://rustysoffroad.com/mm5/merchant.mvc?Screen=RIGS

Tiberius

I'm very interested in seeing a build thread, I'm currently debating on doing a small block swap, and making my Cherokee srt8 themed

hercman

For a BB you may need to massage the width of the engine compartment. You may not be able to run regular manifolds either. I have a SBC in mine and the only thing that would fit for exhaust was block hugger headers.

If you look at my photos you'll see how little room there is with the SBC.

zraffz

Where your headers hitting the inner fender skins or the unibody rails? A big block (off the top of my head) is 2" wider and 2" longer if I recall correctly.

With that being said if you fit that without any hacking/smashing, I can fit a big block with a BFH.

hercman

Here's some pics for you to look at in regards to how a SBC fits inside an 85.













It's pretty tight. But with enough time and money anything is possible.

zraffz

It won't be that bad. Exhaust will be a nightmare, radiator will have to get moved further forward, and by the looks of it I won't be able to run power steering.