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Chevy 350 swap

Chevy 350 swap
B

bearsden

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Location
Norwalk,Iowa
Vehicle(s)
2002 ford f150 4wd,1989 chevy suburban 4wd,86 cj7 ,67 nissan patrol(sold)
I have a 1986 CJ7 that when I bought it, came with a 700r Transmission bolted up to the inline 6 cyl. I have been running with that for roughy 2-3 years. I have a sbc 350 from a 1978 chevy pick up that I purchased from a friend about a year ago and have always been thinking about installing it in my cj. I have read alot of info on this but none that has had the tranny already in the jeep. I also have a Dana 44 rear diff. that I got out of another 86 CJ7 in the shed. thinking about swaping both. I dont do any heavy wheeling but do trail ride and hunt alot. any thoughts from the experts would be greatly appreciated !!!
 
What's wrong with the present I6?

Swapping engines is a can of worms. Some cans are bigger, some come with more worms in them.

Picture012.webp
 
Thats beautiful !! my motor doesn't seem to have a lot of power and bogs down bad when i get to a hill of any kind.And I do have some driving to get to some of my hunting spots. The 700r goes in and out of Overdrive constantly. If i have to spend money thought i would go with the v8..
 
bearsden said:
Thats beautiful !! my motor doesn't seem to have a lot of power and bogs down bad when i get to a hill of any kind.And I do have some driving to get to some of my hunting spots. The 700r goes in and out of Overdrive constantly. If i have to spend money thought i would go with the v8..
Click to expand...

:)
The 700R4 is a great Transmission for just about everything. 3.06 low gear x about 1.6 multiplication gets you a near 5:1 in low gear.....in 4th it's 30% Overdrive . You didn't say what gears you have in the axles , but normally for a Jeep that is looking for some off road performance 4:88's seem to work.

If your Transmission is hunting between 3&4 it could be something that is as simple as adjusting the shifting cable.........they all have a pressure regulated valve body so with the right shifter that can be manually shifted. But without knowing more about whats going on it's just a guess from this end.

They are a little long so not sure what your drive shaft length is? You may even be better off length wise with the shorter V8 vs the inline 6.

Transmission coolers , the right stall speed converter, and gearing is important.

I'm a big fan of the 700R4 platform .......In my latest build I'm using the modern version of the 700 a 4L70e electronic tranny behind a LS 376 motor.

Again a great Transmission , but perhaps not for everyone.

:D:D:D:D
 
gearing currently is 3.73's. It looks to me like both front and rear drive shafts have been modified. I did take it to the local tranny guy whom i trust very much and he adjusted it for me and told me i would have to manually switch it to avoid the back and forth thing or i will burn it up. I have been driving it like that for quite some time with no issues.
 
Okay, the I6 is breathing hard. Might As Well, go with the 350. Is it a carb'd or EFI engine? I'm assuming carb, because it's a 78. MAW consider going the full route and getting a junkyard TBI to swap.

There is a ton of aftermarket support for the GM/Chevy swap.

When I did my Ford 5.0 swap, there wasn't as much in the way of aftermarket support. You should have no problems (other than $$$) dropping the SBC into the CJ.
 
I don't think your swap will be that hard. Since the tranny is there that means the driveshafts are all set. You basically need your motor, motor mounts, new exhaust, some flexible fuel line to hook up the the 350 fuel pump, 350 conversion radiator and the wiring harness will need to be modified for the new ignition. the tranny position should not change because you can adjust were you place your motor. Your Dana 44 is a good swap and worth it so long as the gears are the same.
 
What size tires are you run'n on that '7'?
LG
 
Kane said:
I don't think your swap will be that hard. Since the tranny is there that means the driveshafts are all set. You basically need your motor, motor mounts, new exhaust, some flexible fuel line to hook up the the 350 fuel pump, 350 conversion radiator and the wiring harness will need to be modified for the new ignition. the tranny position should not change because you can adjust were you place your motor. Your Dana 44 is a good swap and worth it so long as the gears are the same.
Click to expand...
what motor mounts are you guys suggesting,I've been going through all the searches and it seems like novak and mountain off road get brought up a lot. I don't recall seeing a whole lot on the wiring end of it but i'll do some more reading. Thanks!!!!!!:chug:
 
HackFabrication said:
Okay, the I6 is breathing hard. Might As Well, go with the 350. Is it a carb'd or EFI engine? I'm assuming carb, because it's a 78. MAW consider going the full route and getting a junkyard TBI to swap.

There is a ton of aftermarket support for the GM/Chevy swap.

When I did my Ford 5.0 swap, there wasn't as much in the way of aftermarket support. You should have no problems (other than $$$) dropping the SBC into the CJ.
Click to expand...
yes it is carbed,and will be going with the quadrajet from what i've been reading. I do worry alittle about the clearance of the distributor, it looks to me like the PO moved the skid plate back to accomadate the new tranny and just looking it appears that i might have to pull everything forward..where the bell housing is seems to be back to far.But i guess i'll cross that bridge when i get to it. You guys have really helped me in the past and can't tell you how much i appreciate it.My internet sucks where i live so i don't always get back right away,but I'm reading everything i can! I'll try to post as much as i can!! Thanks again!!!:chug:
 
Are you sure those are 3:73 R&Ps?
OEM factory was either 2:73 or 3:31.
Sounds more like 2:73.........:confused:
How was your ratio confirmed?
LG
 
Lumpy Grits said:
Are you sure those are 3:73 R&Ps?
OEM factory was either 2:73 or 3:31.
Sounds more like 2:73.........:confused:
How was your ratio confirmed?
LG
Click to expand...

I couldn't find info on rear but front was tagged 3.31 43-13 and the other numbers were 8953004038 . I think I posted these before and someone told me 3.73 for some reason.
 
33" tires and a 3:31 R&P are a pour combo. BTDT!
Do you have a 'Model 20' rear or a Dana 44 ?
LG
 
A 350 with a mod 20 is a poor choice.
Get a set of 4:10 R&Ps along with Moser 1 piece axles and you'll be liking that 6(IF it's run'n 'rite')a whole bunch more.
LG
 
Lumpy Grits said:
A 350 with a mod 20 is a poor choice.
Get a set of 4:10 R&Ps along with Moser 1 piece axles and you'll be liking that 6(IF it's run'n 'rite')a whole bunch more.
LG
Click to expand...

Will that get me a little more top end? And should I get 4.10 R&P for the Dana 44 or m20?
 
Motor mounts: M.O.R.E. Great customer support, great product. Pay the $$$ and don't look back.

Gearing: 33" rubber with the O/D Transmission behind the I6, is probably begging for 4.56. Perhaps the 4.10's, but I don't know if you will be able to hold the hills at freeway speeds with the I6. Other's have more experience than I do with the I6. Can you get a set of 4.27's for the 30/20 combo (I don't know)? You might be able to get away with 3.73 if you swap in the V8. In any case, if you keep the AMC20 , get a set of Moser 1 piece axles.
 
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HackFabrication said:
Motor mounts: M.O.R.E. Great customer support, great product. Pay the $$$ and don't look back.

Gearing: 33" rubber with the O/D Transmission behind the I6, is probably begging for 4.56. Perhaps the 4.10's, but I don't know if you will be able to hold the hills at freeway speeds with the I6. Other's have more experience than I do with the I6. Can you get a set of 4.27's? You might be able to get away with 3.73 if you swap in the V8. In any case, if you keep the AMC20 , get a set of Moser 1 piece axles.
Click to expand...
The more i think about it i'm going to go through with the swap,i've been working on the motor for awhile and its something i've always wanted to do since the day i bought it with the 700r already in it. I will get the more mounts and not look back.I will swap out the rear end for the Dana 44 . I have a set of g2 3.73 r&p's for the Dana 44 that i bought while i was in az.For some reason i thought thats what i had in m20 Costly mistake if i can't use them. I still don't know how i screwed that up. L grits just brought that to reality for me. We have no good parts store around here and i grabbed them while i was out there all the while thinking thats what i had actually carried them home in my suit case. I will never hear the end of that one from the boys at work.....i'm going to go make a drink.
 
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