360 in YJ

[mika01]

I'll be putting in a 360 in my YJ and would like to know if anyone has any recommendations on headers for the YJ. Anyone with past experience would be great.

[pyagid]

as far as putting it in the YJ, i know advance adapter makes a set of mounts, I just bought them for the YJ frame i am using on my CJ project. I have always run heddman headers in my CJ, although have herd people have problems with them not sealing properly I have never had a problem.

I am thinking for this new project I might go back to normal manifolds though and run a single exhaust instead of dual

-Paul

[mika01]

Thanks Paul,
I have another question, I pulled the intake of the motor and it looks likes its been to war and back. Ugly! I'm thinking of getting a new intake and not sure between the Edelbrock "Air Gap" or the "Torker". Which one would you recommend? Also do I have to use the original valley pan or simply a set of head gaskets? Thanks for your help.

[tufcj]

Just my $.02 . :wink: Unless you're revving it over 3000 RPM and holding it there (like mud bogs), go with the air-gap or performer series. Use a new valley pan (about $20), it keeps the hot oil off the bottom of the manifold. Be sure to transfer the factory tin baffle from the stock manifold to the torker or performer (I don't know if the air-gap uses it). I've seen instances where oil is sucked thru the PCV system without it.

I ran a torker on my CJ for a while, it really hurt the low RPM torque. I run a performer now, and it works better for low RPM rock crawling. Bought a R4B (long discontinued Edelbrock), which will go on next year when the engine (360) gets a full rebuild.

Bob
tufcj

[mika01]

Thanks for the info Bob, greatly appreciated. Since you also have a YJ frame with AA motor mounts what Headers will you use? I want to make sure I get some that dont interfere with the mounts. Thanks a bunch.

[mika01]

Bob is there a specific reason your going to use a R4B intake? Are there any perrormance advantages over a new Performer intake? Iknow they factory options on police pack 401 but performance wise are they better then a new Performer?

[tufcj]

Paul has the 360 YJ. He'll have to answer the header question. I got rid of headers because I live in a smog zone now. I have to have the AIR pump and smog rails, it was easiest to just keep the factory high flow manifolds. I run thru a singe 3" exhaust with a free flow cat, and I don't notice any loss of performance. I seldom rev it past 3500.

The R4B is still (supposedly) the best "all around" manifold. I don't know if it will make any difference in performance. I have one on my AMX, and have a 70-up version on the shelf that I want to try. I may not even like it, but as long as the engine is apart, that's what's going back on. :? :?

Bob
tufcj

[pyagid]

i Have not put the mounts on yet, nor the motor or anything. I dont think there is going to be a problem with the headers clearing but wont be sure until i get it all fitted

-Paul

[mika01]

Out of curiosity, could either one of you tell me what probable horsepower and torque numbers I should expect if I install an R4B intake together, 600 CFM carb with a set of 291C heads on an 89 360? I have no idea what to expect so any numbers would be welcome.
Thanks
PS you guys are awesome. Very knowledgeable and experienced. Definitely the best board I’m on.

[Mudrat]

There's a couple R4B's on e-bay right now ... http://search.ebay.com/r4b_W0QQfkrZ1QQfromZR8

I went with the performer for the 360 going in the Waggie (bored, balanced, blueprinted). Mainly 'cause I bought it before these ebay items ...

Pat

[tufcj]

It's hard to say with just a head, manifold and carb swap. I'd say somewhere around 50-75HP over stock, providing the carb is dialed in properly. The 291 heads have a little better compression, but actually don't flow as well as later heads. They also have a slightly smaller intake valve (1.62" vs. 1.68"). I've found that AMC V-8s respond VERY well to mild porting. Money or time spent for porting is always worth it. Next is cam selection. An engine is a big air pump, intake/exhaust get it in/out, but you cam helps push it thru. If you stay with a stock cam, that becomes your restriction point. I've had good luck with the Edelbrock Performer cam in my 360, I've also heard good things about the Summit 8600 or 8601 cams. I run a Crower cam in my AMX, but it's way too radical for off-roading.

Desktop dyno for my 69 390 estimated 450HP. It's balanced, 10.1:1 compression forged pistons. It's got 291 heads w/stainless valves (1.68/2.025) with some extensive port/polish work. Crower stage 3 "street beast" cam 282/292 duration, .512/.525 lift. Crane gold roller rockers, R4B intake, Hooker super comp 1 7/8" headers (jet hot coated), run thru dual 2 1/2" exhaust with an "X" pipe. Carb is an Edelbrock 750. I also run a 2500 stall converter (auto trans), and 3.73 gears in the rear. As soon as I get the interior in, we go to the dyno to get a real measurement. It feels and sounds strong, so I think the estimate is close.

Bob
tufcj

[mika01]

Wow! 75HP over stock, I'd getting close to 300HP! Thats fantastic! Probably not much for some of the harder sore guys out there, but for someone who is ditching his 258 its going to be almost triple what I have!! Now if I could just stay of the little pedal on right!
Thanks a bunch
PS sounds like you have one hell of a monster on your hands.

[Mudrat]

Probably not much for some of the harder sore guys ...

Um .. some of us are not harder, but DEFINATELY sore Mika :t:

[mika01]

Darn that fat finger syndrome!

[fjr1300]

I am also putting a 360 in an 88 YJ with a 999 auto, from what I've heard I can use CJ headers - is this correct?

Thanks for any info

[mika01]

Not long ago there was a Jeep rallye in CT and I saw a couple of YJ's with the 360 installed and yes one of them had the CJ headers. I believe they were the Headmens. He ran it with dual exhaust and converters. Of course the exhaust is going to have to be customs but it did work. Now that I think about it the passenger side botom header tube was dented to clear the mounts. I trial assembled mine (not Headmen) and they clear nice.