How to fit a big block into a YJ?

Craig

New member
RE: FS: "If you can read this... ROLL ME OVER!" de

Hey. I have the opportunity to get a 454 BB at a real cheap price. Just wondering in anyone has ever seen a big block in a YJ and what kind of mods needed to be done to get it to fit.
 

RE: Gear ratio after lift

Take the fenders and hood off and it'll work.... :lol: :lol: :roll:
 
RE: Brake hoses on the way

I've seen it, and it'll fit with some creative exhaust and steering work. My 350 fit in my '88 YJ with plenty of room to spare.
 
Ya I've seen it done several times too. Obviosly you'll need all new mounts and everything (might have to get a little creative there)....along with a different transmission, t-case, axles, etc. You may have to trim or re-shape the metal wheel-wells, but that wouldn't be all that difficult.

As far as physically fitting in there--it shouldn't be much of a problem.
 

But the main ??? is WHY.............Are you going to put d60 f/r new transmission/radiator/tc/and everything else i forgot? Plus lets not forget about the $3 gal gas at maybe 5-6 mpg...............just a thought
 
RE: Busted rear shock mount

The exhaust manifolds are the major concern. You will have to either acquire some block huggers or install a body lift so the engine will sit higher. The other problem is overheating. It's hard to fit a large enough radiator in a Jeep to cool that monster. I have seen it done though.
All things considered, you will get plenty of performance and less hassle from a small block. The upfront price may be a drop in the bucket compared to the overall price of modifying the entire Jeep to withstand big block power. If its a carbed 454, I wouldn't even waste my time. I'd take a fuel injected 2.5 over a carbed 454.
 
It is fuel injected. I probably won't do it I was just considering it since I can get it at a good price. Just wanted to know if it would even fit to begin with. If I don't get this it's most likely gonna be a 350 instead. I'd like to eventually turn my jeep into a "trail only" weekend toy to bash around.
 
There's a local mud racer here that runs an aluminum headed 730hp(without the nitrous) stroked Chevy BB in his YJ.....on a race prepped 1 ton drivetrain with 44" Boggers. He's fast. :lol: There was a guy around here with a Samurai that had a 454 in it, but I haven't heard anything about it in a while. There has been a couple of guys put them in CJs, but they were more for show than anything else. It will go in relatively easy, considering....

Weight is of course a factor here. The handling of a lifted 93.5" wheelbase with that much mass at one end of it is less than great. In factory form the later truck 454s weren't exactly exciting, but that torque is going to rip the YJ drivetrain apart in short order. I wouldn't see the big deal if you really wanted to do it, but it will take alot of other mods to the whole vehicle. I think it would be cool, but a smallblock really would be a better choice if you don't plan on making insane power. But, a decent smallblock is going to require similar mods :wink:
 

How would the frame hold up to that much power? If you go with the 454, a few things to complement the motor would be nv4500/th400, dual d300's, d60/d60 or d60/d70, 4-link, reinforced or aftermarket frame, stretched wheel base, 44" boggers complete cage, you get the idea...
 

hmmm i think it might get decent gas mileage considering the load it would be under, i don thtink it would be that bad really. go for it and tell us when your done
 
THANKS!

I'm sure it would get at least 15mpg...probably even closer to 20 if it's running good.

And ya, the frame would hold up fine, most likely. You might want to simply add a crossmember and do a little reinforcing near the engine if it looks like it needs it.
 

Saw a great article on a bi block conversion in Off road adventures mag April 2005- guy took his body off, cut it in quarters and dropped it on a 3/4 ton chevy chassis, then fill in the gaps with sheet metal. probably easier than modifying a jeep chassis. Look a lot like a Hummer. see oramagazine.com
 
GaryMB said:
I don't see a big block getting 20mpg...

If it's runnning real good and is in a light-weight Jeep...I don't see why not. With the right gears and a light vehicle, the engine doesn't have to work very hard at all--wich is the key to good fuel milage :wink: .

One of our trucks with a 454 in it gets around 16-17mpg combined city/highway driving. We also built a '32 Ford Roadster with a 460 and it got a little over 20 mpg until it got supercharged :D ...and that was a pretty built up engine too
 
hahaha did someone say big block in a samurai??? that sounds like some funny stuff. can i tag along and watch?? why in the hell would you want a big block?? some one help me understand this. i come from a racing background and my small block turbo car smokes the **** out of most big blocks i have come across including big block turbo cars for those who want to make the comparison. what would be the advantage of have a big block?? i just do not see it in crawling i mean you can gear it to do what ever you want so why waste the money. and to who ever thinks 20mpg please pass what ever it is that you are on i have been looking for a good connect on something that good. my 454 in my truck gets 15 on the highway with just me in it and no load. if you are re gearing and doing everything for off road there is no way in the world you are gonna get 20mpg. i can see the roadster maybe but not a jeep with lifts gears and off road tires.
 

hahaha did someone say big block in a samurai??? that sounds like some funny stuff. can i tag along and watch?? why in the hell would you want a big block?? some one help me understand this. i come from a racing background and my small block turbo car smokes the **** out of most big blocks i have come across including big block turbo cars for those who want to make the comparison. what would be the advantage of have a big block?? i just do not see it in crawling i mean you can gear it to do what ever you want so why waste the money. and to who ever thinks 20mpg please pass what ever it is that you are on i have been looking for a good connect on something that good. my 454 in my truck gets 15 on the highway with just me in it and no load. if you are re gearing and doing everything for off road there is no way in the world you are gonna get 20mpg. i can see the roadster maybe but not a jeep with lifts gears and off road tires.


The torque the big block would put out would be great help in a mud bog running some 44's.I am not saying a small block wont do the job.
 
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