455 Pontiac in a 79 Jeep (FSJ) *UPDATED*

[skid2964]

I made mention of this setup in another post and was asked to supply more info here.

I bought my 79 Jeep Cherokee earlier this year and found the 401 in it needed a rebuild, the more I researched the AMC, the more I hated sinking any money into it. I used to race Pontiacs years ago so I decided a 455 would be perfect! 4x4's (especially 5000lb ones) need lots a low end torque!

The swap is fairly easy as far as the drivetrain goes. The Jeeps with the Quadratrac 4 wheel drive system used an AMC bolt patterned GM Turbo 400 transmission, so I acquired a Buick-Olds_Pontiac bolt patterned TH400 and will have the original output shaft installed in it to mate up to the Quadratrac transfer case.

The motor mounts, I thought would require a big fabrication job, but I have found this is not the case. I mocked up the empty 455 block and empty TH400 case in my Jeep this past weekend and found the motor mounts are VERY close! (see pics). This makes things very easy! All I need is some flat adapter plates. ( I may market the adapter plates ).

The only things left will be the AC compressor and brake booster. "vintageair.com" makes brackets for a Pontiac to mount a new style compressor, but I think I will fabricate mounts for my original York compressor. The brake booster looks like it will interfere with the driver's side valve cover, two options; use GM hydroboost or get a reduced diameter brake booster from summit racing, I think I will do the latter. (actually 3 options, a 2 inch body lift will make it clear also)


http://www.laniebaby.com/temp/mockup/mockup1.jpg

http://www.laniebaby.com/temp/mockup/mockuptop.jpg

http://www.laniebaby.com/temp/mockup/mockupleftmount.jpg

http://www.laniebaby.com/temp/mockup/mockuprightmount.jpg

http://www.laniebaby.com/temp/mockup/mockupbottom.jpg

[skid2964]

I made mention of this setup in another post and was asked to supply more info here.

I bought my 79 Jeep Cherokee earlier this year and found the 401 in it needed a rebuild, the more I researched the AMC, the more I hated sinking any money into it. I used to race Pontiacs years ago so I decided a 455 would be perfect! 4x4's (especially 5000lb ones) need lots a low end torque!

The swap is fairly easy as far as the drivetrain goes. The Jeeps with the Quadratrac 4 wheel drive system used an AMC bolt patterned GM Turbo 400 transmission, so I acquired a Buick-Olds_Pontiac bolt patterned TH400 and will have the original output shaft installed in it to mate up to the Quadratrac transfer case.

The motor mounts, I thought would require a big fabrication job, but I have found this is not the case. I mocked up the empty 455 block and empty TH400 case in my Jeep this past weekend and found the motor mounts are VERY close! (see pics). This makes things very easy! All I need is some flat adapter plates. ( I may market the adapter plates ).

The only things left will be the AC compressor and brake booster. "vintageair.com" makes brackets for a Pontiac to mount a new style compressor, but I think I will fabricate mounts for my original York compressor. The brake booster looks like it will interfere with the driver's side valve cover, two options; use GM hydroboost or get a reduced diameter brake booster from summit racing, I think I will do the latter. (actually 3 options, a 2 inch body lift will make it clear also)


http://www.laniebaby.com/temp/mockup/mockup1.jpg

http://www.laniebaby.com/temp/mockup/mockuptop.jpg

http://www.laniebaby.com/temp/mockup/mockupleftmount.jpg

http://www.laniebaby.com/temp/mockup/mockuprightmount.jpg

http://www.laniebaby.com/temp/mockup/mockupbottom.jpg

[PMDRACER]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> The brake booster looks like it will interfere with the driver's side valve cover, two options; use GM hydroboost or get a reduced diameter brake booster from summit racing, I think I will do the latter. <HR></BLOCKQUOTE>

Save your money. Get a 10" dual-diaphragm booster from a '78-'87 A/G-body car. Cost you $10 out of the yard, and $3 in parts. See my site here for the details. (http://home.socal.rr.com/tigerefi/)

BTW - your Jeep looks alot like the "Golden Eagle" J-10 a friend of mine in High School had. Used to tear up the hills in that thing!

[PLAY400]

Since you have to make the plates for the motor mounts you may want to consider coupling the 2 sides together with some sort of crossmember to prevent the frame from spreading under torque. My kid was showing off with his CJ5 rock climbing in low gear and pushed the passenger side of the engine below the frame. Tore the motor mount right off. Going to fabricate a mounting system like Summit sells for it this year.

[skid2964]

PLAY400,

That is an excellent idea, I had thought about it, but had not seriously considered it. Since this engine can make over 500 ft lbs of torque, I think I will do it ... Thanks

[ddouble]

Thanks skid,

That is very interesting. I've watched and helped (well I thought I was helping http://forums.performanceyears.com/groupee_common/emoticons/icon_razz.gif) with two 258 to 360 swaps in CJ's. It really doesn't look like much more work to drop in the 455 on your wagon. I have sent this thread to my friend with the Jeeps. Can't wait to hear from him.

Dan

[skid2964]

You are welcome ....

I am creating blueprints for my machinists to make adapter plates now. I will make these plates available to others once I prove they are going to work properly.

[skid2964]

I put the heads and intake on it this weekend, the heads were at the machine shop last weekend getting new valve guides and being checked for cracks and straightness, now I have thewm back to do some port work on them.

Starting to look like some progress is being made! I bought that performer intake used, I WILL be stripping the blue paint off of it! will paint it black http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif .

http://www.laniebaby.com/temp/mockup2/front.jpg

The headers seem to fit very well, except for the bump stop on the passenger side being in the way, I think I can just cut it off, I have two other bump stops anyway.

http://www.laniebaby.com/temp/mockup2/rightheader.jpg

http://www.laniebaby.com/temp/mockup2/rightheaderobstruction.jpg

http://www.laniebaby.com/temp/mockup2/leftheader.jpg

The drivers side head would not even go on with the brake booster in place! I think hydroboost will be a necessity!

http://www.laniebaby.com/temp/mockup2/boosterclearancecloseup.jpg

and finally, it looks level too!

http://www.laniebaby.com/temp/mockup2/level.jpg

[6567GTO]

Cool project with some great pics! Keep us informed of your progress. I've gpt a 94 Jeep Grand Cherokee. I wonder how a Pontiac would fit into that!? LOL

[skid2964]

less room, but I bet it would fit! http://forums.performanceyears.com/groupee_common/emoticons/icon_biggrin.gif

[Jandro]

I have a 96 Jeep GC and have an extra 455, I've seriously thought of using it, when the original motor kicks it, BUT I'd have to be somewhere they didn't require emissions inspections
http://forums.performanceyears.com/groupee_common/emoticons/icon_frown.gif