CJ 7 SBC Conversion

[Lightnin 1]

Hey guys, I'm new here. Looking for some insight on a small block chevy conversion on my 84 CJ. Got a 4 cyl. now. Building a mild mannered 350 to drop in. Any technical advice will be greatly appreciated. Have a bell housing off a 4cyl. GM. Was told that it would work fine. Need to find out what else I got to have to make this thing work. Thanks.

 

[Old Dog]

Have you checked out these sites yet
Novak Jeep Conversions - Home
AdvanceAdapters.com | Engine & Transmission Conversion Adapters - Advance Adapters
Both sites have lots of info and also sell everything you need.
There are others that sell motor mounts such as Mountain Off Road- M.O.R.E. Manufacturer Direct Pricing on Jeep parts for Jeep YJ, Jeep CJ,Jeep TJ,Jeep JK and Jeep XJ models, quality jeep off road bumpers
I have an auto in mine so I can't help much on the manual Transmission stuff.

 

[Scooter402]

I had a T-176 behind a 383 stroker in mine many moons ago. You'll need a 168 tooth flywheel for your 350, a standard 10.5" clutch from a truck will work. Just make sure that the input shaft on your Transmission is a 1-1/8" coarse 10 spline, and everything should work fine. If you change the factory offset (I believe it is 1-1/2" toward the driver's side), your clutch bell crank will not be long enough. You'll want to leave that where it is, unless you want to lengthen your bell crank. I messed that one up once.

Other than that, it's a set of motor mounts from either Novak or Advance Adapters, unless you make your own. Then you'll need a SBC - Jeep CJ radiator, and then hook up a few wires and you'll be off and running in no time.

Exhaust -- well, that one's up to you and your state's laws. If you need all the emissions stuff, that will make it a little more difficult. The easiest thing by far is fenderwell headers and side pipes, if you don't mind the muscle car type rumble. I think they sound pretty nice, but others like to use factory manifolds or block hugger headers and leave all the exhaust between the frame rails. Post up a build thread in the build section and I'm sure you'll get more help and opinions than you ever wanted.

 

[CJ]

Don't forget the bit of electrical, cooling (rad and hoses), cables and little knick knacks - it all ads up so plan accordingly.

 

[Petescj]

I'll chime in a little in the Transmission department. It would be helpful if we knew what you were planning on using the Cj for 1st but we'll put the cart before the horse for now.

Your 84 with a 4 cylinder has one of the weakest transmissions in the Cj line. Throw it away. It will never hold up under V-8 power. If you already had a fresh T-176 to throw in it Id say ok use it. Its not a bad Transmission and can handle moderate ( stock ) V-8 power.

Now for me it doesnt make alot of sense to to go thru putting in a Chevy V-8 without upgrading to a stout Transmission . If I remember correctly its easier and cheaper to adapt the Dana 300 you have to a Chevy Transmission like the SM420 or SM465 than use the T-176 from a Cj. OLD DOG gave you the link for Novaks site. Plug in some different options and read accordingly. Thats a great site for conversions.

Hey guys, I'm new here. Looking for some insight on a small block chevy conversion on my 84 CJ. Got a 4 cyl. now. Building a mild mannered 350 to drop in. Any technical advice will be greatly appreciated. Have a bell housing off a 4cyl. GM. Was told that it would work fine. Need to find out what else I got to have to make this thing work. Thanks.

 

[Lightnin 1]

I'll chime in a little in the Transmission department. It would be helpful if we knew what you were planning on using the Cj for 1st but we'll put the cart before the horse for now.

Your 84 with a 4 cylinder has one of the weakest transmissions in the Cj line. Throw it away. It will never hold up under V-8 power. If you already had a fresh T-176 to throw in it Id say ok use it. Its not a bad Transmission and can handle moderate ( stock ) V-8 power.

Now for me it doesnt make alot of sense to to go thru putting in a Chevy V-8 without upgrading to a stout Transmission . If I remember correctly its easier and cheaper to adapt the Dana 300 you have to a Chevy Transmission like the SM420 or SM465 than use the T-176 from a Cj. OLD DOG gave you the link for Novaks site. Plug in some different options and read accordingly. Thats a great site for conversions.

I got to research which tranny I'm working with here..... I'm thinking its a T-4 but a few websites say that this year model could be using the T-176 . Really trying to get an idea of what I really want. Thanks everyone for the feedback.

 

[Lightnin 1]

Don't forget the bit of electrical, cooling (rad and hoses), cables and little knick knacks - it all ads up so plan accordingly.

Yeah, I'm finding this out quickly!!!!! By the time I get done with this project, I will probably have spent $5 to$6K.

 

[Petescj]

http://www.jeep-cj.com/forums/f105/manual-cj-transmissions-12112/

I got to research which tranny I'm working with here..... I'm thinking its a T-4 but a few websites say that this year model could be using the T-176 . Really trying to get an idea of what I really want. Thanks everyone for the feedback.

 

[Kane]

For 5 to 6k you could do a 5.3 vortec (truck version of the LS) motor with tranny and have a better gas mileage reliable power house

 

[Lightnin 1]

After everything I have studied, looks like I'm toting a T-4 .... Did have an old truck puller give me a tranny. Don't know exactly what it is but it's got a heck of a granny gear in it. Came out on a 71 Chevy k 20. He kept saying it was a Muncie, but I thought they just had car transmissions.. Hoping this could possibly be a T-18 but probably won't be that lucky.

 

[Petescj]

Its probably a SM420 or SM465 if it has the granny low and came out of a Chevy. I have the SM420 to put in mine. It is a Muncie. Read here:

The GM Muncie SM465 Transmission - Novak Conversions

Your in pretty good shape with having the T-4 . Your bellhousing can be machined to accept the GM Transmission .

After everything I have studied, looks like I'm toting a T-4 .... Did have an old truck puller give me a tranny. Don't know exactly what it is but it's got a heck of a granny gear in it. Came out on a 71 Chevy k 20. He kept saying it was a Muncie, but I thought they just had car transmissions.. Hoping this could possibly be a T-18 but probably won't be that lucky.

 

[BIGTRUCKNUT]

Its probably a SM420 or SM465 if it has the granny low and came out of a Chevy. I have the SM420 to put in mine. It is a Muncie. Read here:

The GM Muncie SM465 Transmission - Novak Conversions

Your in pretty good shape with having the T-4 . Your bellhousing can be machined to accept the GM Transmission .

Could also be an early Chevy NP435. Everything I've read says that the Chevy NP435 is not desireable for a Jeep swap because Transfer Case adapters and new mainshafts won't work in it. Something about a roller bearing used in the Chevy version. I don't know, mine is working fine (for over 15 years) between a SB 350 and Dana 20 .

Bottom line, figure out what you have and put it in - all are better than a T-4 or T-176 .

 

[WSS]

After everything I have studied, looks like I'm toting a T-4 .... Did have an old truck puller give me a tranny. Don't know exactly what it is but it's got a heck of a granny gear in it. Came out on a 71 Chevy k 20. He kept saying it was a Muncie, but I thought they just had car transmissions.. Hoping this could possibly be a T-18 but probably won't be that lucky.

You would be luckier if it was a Muncie SM-420 (stewart/muncie). 1:7 1st really low and really strong. I have one in mine and used a advance adapter to a Dana 20 tc.

 

[Lightnin 1]

How does the factory clutch linkage match up with the 465?? Or should I ask, what kind of modifications have to be made for it to work.

 

[Scooter402]

I'm only shooting in the dark off of memory, but there should be a manual clutch fork coming out the side of the bellhousing similar to what you have already. There may be some modification needed to your adjustable push rod (lengthen or shorten, I don't really know), but that "should" be about it. You might have to change the length of your bell crank so the push rod lines up directly with the socket in the clutch fork, but it'll make more sense when you get the Transmission in there.

 

[BIGTRUCKNUT]

My suggestion, and what has worked great for me since installing my SB 350 over 15 years ago, is to find a hydralic clutch bellhousing/slave cylinder from a later '80s era Chevy/GMC truck. I then used the clutch master cylinder from an early '80s 4 cylinder CJ bolted to the firewall and cobbled together a hose between the two. Greatest benefit is no clutch linkage binding or loss of pedal travel when the frame is crossed up and parts are readily available if you need to replace.

 

[Lightnin 1]

Still in the planning stage on this Jeep...... Looks like I'm going with a GM Crate engine.(290 HP). Going throught the SM 465. Everything looked good in it ,but while it's torn down, might as well rebuild it. The only thing I have not decided on is headers. I love the sidepipes, but thinking for a daily driver, might be too loud. Anyone run shorty headers w/ 2 1/2" pipe & Flowmasters?? Would like some feedback on this...Thanks

 

[BIGTRUCKNUT]

Sounds like a great plan, can't really go wrong with a GM crate motor and a 465. As to your exhaust decision, I have sidepipes and turnouts on my daily driven CJ5 with a Chevy 350 and it is loud. Some days I'm actually embarrassed when I stop at a light and folks next to me roll up their windows. When these headers finally rust through I'm going with full length headers inside the frame rails, a quiet(er) muffler, and a 3" pipe out the back.

 

[Lightnin 1]

Sounds like a great plan, can't really go wrong with a GM crate motor and a 465. As to your exhaust decision, I have sidepipes and turnouts on my daily driven CJ5 with a Chevy 350 and it is loud. Some days I'm actually embarrassed when I stop at a light and folks next to me roll up their windows. When these headers finally rust through I'm going with full length headers inside the frame rails, a quiet(er) muffler, and a 3" pipe out the back.

Is there any advantage to running full length headers vs. the shorty headers??? I'm just looking for a good deep sound and no popping.

 

[BIGTRUCKNUT]

Is there any advantage to running full length headers vs. the stubby headers???

Better overall flow from full length headers, but probably negligible difference in performance with this application. Stubby headers are often easier to plumb the exhaust system from, especially if staying with stock exhaust system, and it's not usually an issue getting the starter out without messing with the headers/exhaust system. Stubbies are also good in tight engine compartments or in swaps that are not supported well by the aftermarket. That said, full length Jeep/SB Chevy conversion headers usually fit well in the specified application since they are designed to clear stock Transmission /transfer cases. Personally, I'm partial to full length whenever reasonably possible.