Build Thread Attempting 350 sbc,700R4,NP208 in CJ7

Build Thread Attempting 350 sbc,700R4,NP208 in CJ7


Phoenix, AZ
1986 CJ7
I'm going to attempt a V8 conversion with a 350 sbc, 700R4 and a NP208 transfer case in my 1986 CJ7 . Has anyone done this? What can I expect as far as the length of this set up?

Thanks for any info!:notworthy:
I know the 700r4 is a long trans. I bet your going to need a cv rear driveshaft...
Good to know. Now the question is, do I buy a $550 adapter to fit my Dana 300 ? I would like to not spend the $ till it breaks, but how much doest it cost to fix the drive shaft issue?

On a separate note, everyone I have dealt with on this site is very knowledgeable and friendly. Thank you to everyone helping me make this V8 conversion possible.
I'd run it till it brakes (but that is just me) :)

Once you do the swap you'll be able to measure to have your drive shafts modified (lengthened or shortened). Depending on what you need to do a local shop may be able to take care of you or you may need a CV shaft. If you need a CV shaft -->> Tom Woods Drive Shafts <<-- Tom Woods can most likely take care of you. Here is a great tech article on driveshaft geometry -->> Tom Wood's Custom Drive Shafts - Driveline 101

The big problem is that if you make the swap and DON'T put the 300 in, you'll probably have to have some drive shaft work done again. I can't be sure of that though, and if you do - it will most likely be very minor.
Thank you very much for the compliment, there is a great group of members on this site! :chug:
the best advice I can give you is expect to spend a lot of money if you go through with this.
doing a 350 costs more than you think. There is a lot of little things that pop up that add up to big bucks. Every thing leads to something else that costs more money.
That combo is real long for a CJ7 and extending your wheelbase sounds good till you find out the gas tank is in the way.:eek:
There will be a lot of custom fab work to do. If you can make parts yourself it helps but if you have to pay someone to make parts and do the work pretty soon you will have enough money in it that you could buy a new jeep.
If only it were as easy as it sounds. Just my 2 cents.
Sounds like I'll just use the NP208 for now if it’s minimal install issues. When it breaks, I'll put in the Dana 300 and modify the axle set up. A great site for axle info CJ! I think I might eventually go Dana 60's. Looks AWESOME LongHorn :drool:. Just being on some what of a budget....I've only had my CJ7 for three months and have about $7000 into the project. Hahaha
Jeeps: Just holes in the trail men pour money into!:laugh:
I know Old Dog, that’s what this turned into. But some of it's my own fault. It runs fine with the AMC 258 i6 / 4.2l in it, but not enough power for me. Plus, I love the way the old CJs look. Soon it will be a whole "new parts" Jeep. Then I will know exactly what I have. The good news is I have a connection who is an off-road fabricator. He builds rock buggies. His shop is at my disposal.
you need to decide which t case youre gonna use first because when you switch to the Dana 300 if youre planning on staying passenger side drop, front drive line clearance doesnt exist at all. the tranny pan sticks out almost right in front of the front output shaft on the Dana 300 . you have basically 4 options when you run the 700r4 or 4l60e with a Dana 300 . 1 you offset everything engine tranny and transfer case an inch and a half to the driver side. 2 you can run a carrier bearing off the frame and use a 2 piece front shaft. 3 is flip the Dana 300 over and run driverside drop with a ford or dodge front end. or 4 you can do like i did and run a full width chevy axle under the front. im not exactly sure on clearance with the 208. youre rear drive shaft is gonna be really short. and if you go spring over you will need a cv shaft. the swap isnt bad as long as you know what you need to watch for. i did this swap only i used an injected vortec 350 and the 4l60e with the Dana 300 . im also sring over and full width axles. let me know if there is anything else youre curious about. but definately figure out your t-case situation before you go together with it.
the CJ7 im building right now has a vortec 350 4l60e and a Dana 300 . never even thought about the front driveline clearance issues until i stabbed the Dana 300 on and looked at. needless to say it kinda freaked me out until i did a little research. also i need to mention when doin the Dana 300 on the back of the 4l60/700r4 if you use advance adapters you will need to shorten your tailshaft to 4.1 inches. the output shaft is hard and i mean really hard. not something you wanna try to cut under your jeep if you wait for your transfer case to break and then try and to throw in a Dana 300 .
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Thanks so much RunUOvr! Now that I have all this info, let me make sure I understand. I want to use the NP208 till it breaks. It's a passenger side drop. Will most likely need a cv shaft in the rear (no more than 3 degrees) I will also want to watch for clearance on the NP208. So will I still need to off set the motor and trany? Also, will I need to run full size axles? Thanks again for your help and knowledge.:notworthy:

Picking up the motor this Sunday and starting the swap in 2 weeks. Really want to get all my ducks in a row.
ok if you wanna run the 208 you will have clearance. look how far out your front putput shaft is is from the right side of your tranny pan. with a Dana 300 your clearance is almost non existant. the problem with swapping later is the drivelines you have built to use the 208 will have to be changed again because i believe the 208 is alot longer. and most 208s have a rear output slip yolk, so you will be doin a sye to run a cv shaft.

now with the Dana 300 you dont not have to run full width axles. when you move the engine tranny and t-case to the drivers side an inch and a half it changest the angle of your driveline enough to give you clearance past the tranny pan. you will need to run a small diameter driveline (tom woods does make one) i think its an inch and a half max diameter next to the tranny pan.

going full width axles changes drive line angle from the axle end and allows you to stay centered with the engine.

i believe youre gonna be money ahead to do the Dana 300 swap now instead of later. youll only have to build drivelines once. you wont be throwing money away on a sye if they make one for the 208. also you wont have to pull your tranny later to cut down the output shaft. the marrying collar from advance adapters will come with a new input shaft for the Dana 300 , real simple swap. also order the advance adapter tranny mount for that kit.

if this was my build being on a budget i would still buy the marrying collar and use the Dana 300 right off and forget that 208. then offset everything an inch and a half. get the advance adapters weld in motor mounts (they are predrilled to offset the engine in different locations). that way you can leave youre axles alone for now. a full width swap is a whole other can of worms that comes with a big price tag.

hopefully im a little clearer than i was before. if you need some pics let me know and i can hopefully get some tomorrow for you before i go to work.
Perfect! Thats what I'm going to do. What adapter would you suggest? Maybe Novak? Need to order motor mounts still. Should have all the parts here by the 19th. The Dana 300 is the way to go in the long run anyway. I will keep the thread upto date and take lots of pics. Thank you for all your help.
It's hard to go wrong with either one. I've used both & they are quality.
when i did mine i used advance adapters. dont know what the difference would be between them and novak. but i will recommend advance adapters to anyone they treated me good when i had questions and have quality products.

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