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V8 Swap

I

IcedXJ

NAXJA Forum User
Location
Spokane Washington
This is not the typical v8 swap question. I am going to put a Chevy 350 into my XJ and I am going to put either TH350 or 700r4 tranny whichever i can find for a good price and an NP231C t-case. I am going to keep the stock rear Dana 35 until later in the project just because of $$$. But when I do do the swap what gearing should I look into, I know if I had the I6 I would run 4.56 with my 32's, but with the amount of torque froma SBC I am unsure.
 
d35 with a 350 = broken axles is 300 extra that much to save for an 8.8 and even an 8.8 is gonna be maxed out if ya put some bigger tires on it. not to mention the d30.
my advice is to rethink or hold off on the 350 swap till ya have the proper drive train to handle it. rember people break d35's in parking lots with stock motors/tires let alone on the trail with a 350 and 32's (please dont' tell me your gonan lock it)
if you absolutly must run the d35 save your coin on gears and run it with stock gears on 32's
 
bj-666 said:
rember people break d35's in parking lots with stock motors/tires let alone on the trail with a 350 and 32's (please dont' tell me your gonan lock it)
Click to expand...

lol, the D35 isn't THAT bad, and is not going to break with stock engine and stock tires. i would think that because of all your power, you should be able to run a higher ratio like 4.10, but it depends on what tires you plan on in the future.
 
okay maybe i should have been a bit more clear. I will never lock or gear the Dana 35, what a waste. I mean I am looking to do the swap before summer comes b/c I am going to Fiji and will not be able to work on my Jeep from thousands of miles away. I figured that the 8.8 would just shred if ever really got on it and knowing me, when this project is done I am going to be making some smoke signals (if ya get my drift). I mean what concerns me most is that it would be very difficult to find a Dana 44 from an Xj...wait nevermind. I think I will pay a visit to my local Jeep Recycling plant.

I mean I would gear the 44 and I guess I could modify a waggy front 44 to fit my XJ then I would gear those. I mean would the 30 hold up to a 350, I mean I am not too crazy when wheeling.
 
i wouldnt go much deeper that 3.55 gears with a small block and 32" tires. the sbc will make a huge difference. i would get stronger axles dana 44 or better and gear at least 4.10 for 35 or larger. remember the 350 is gonna make a larger amount of hp a tq on the top end so high gearing will scream on the free way.
.
 
IcedXJ said:
okay maybe i should have been a bit more clear. I will never lock or gear the Dana 35, what a waste. I mean I am looking to do the swap before summer comes b/c I am going to Fiji and will not be able to work on my Jeep from thousands of miles away. I figured that the 8.8 would just shred if ever really got on it and knowing me, when this project is done I am going to be making some smoke signals (if ya get my drift). I mean what concerns me most is that it would be very difficult to find a Dana 44 from an Xj...wait nevermind. I think I will pay a visit to my local Jeep Recycling plant.

I mean I would gear the 44 and I guess I could modify a waggy front 44 to fit my XJ then I would gear those. I mean would the 30 hold up to a 350, I mean I am not too crazy when wheeling.
Click to expand...

are you planning on staying with 32's ?
i would regear very similar to what you would with a stock motor 4.10-31's 4.56-33's 4.88-5.13 for 35's i beleive the R4 has a good OD so higway shouldnt' be a prob. if your are as hard as you say you are on the truck then the 30 has got to go even if you are light on the gas the 30 is still pushin it. again depending on tire size you looking into a well built 44 or a 60 (or fancy hybrid) 9" would be my suggestion for the rear they have ton's of aftermarket and are fairly cheep to start.
again tire size is one of the main determining factors as to how easily your going to be breaking things. but with a 350 you should be buildign heavy.
 
well I have found a ford 9 inch out of a 1970 Ford Torino. I am going to talk they guy down from 400 bucks (rip off). I could use that for the rear and does the NP231 out of a newer blazer have a passenger or driver side drop. I have found a Dana 44 out of Ford F-150 (76-77) and it is driver side drop. Once again he has the price at 400...I will talk him down. I would have to regear both to make them match and even if I go with the 9" I would still have to regear.
 
Id do the 700R4 if your looking for speed, its has the nice low first gear and a over drive for the highway. Id also put in a converts 1000RPMs higer then your idle, so like 2300-2500, This will give you MUCH more off the line punch and when in low range 4wd at lidle you will not be fighting it with the brakes.
JEgs or summit have cheapies that would be ok for a stock to mild 350. I wish I did that before putting mine in.

Horse power should not have a huge factor on gear selection. It only changes your RPM range and top speed. What do you want your top speed to be and at what RPM. If you are happy with the top speed and RPMs of your 4.0 keep the same gears for your V8. 4.10s Id say for 32s.
 
What do you think about this setup.

Chevy 350 --> 700r4 --> NP241 -->Front Dana 30 (or 44)
-->Rear Ford 9"
(4.11/4.10 gearing)
 
if you want a higher stall in a 700r4 get a v6 converter they stall at about 2200rpm it will save you to bc it is a stock converter. as far as gear ratio goes if you have a good 350 to something healthy dont gear overly high. 4.10's and 33 will scream on the road. i had 265/75/16 bfgs (approx 32") and 3.42 gears in my z71 and it had plent of power even with 160k+ miles on the stock motor. and in 4 low it had way more umph than my jeep has ever had. now im at 35" tires and 4.10 and the truck is geared great, it pulls hard and has a good top end and dosent run to high of a rpm on the hiway i think it would be pulling well over 2300rpms with 33" tires, and my truck is alot heavier than a xj. point being with a v8 id rethink my gear choices unless this is going to be a trail beater only.
 
Well I am going to go bigger than 32" eventually when these wear down but these are brand new. So I am guessing a gear ratio of 3.73 or something in that range would be good for applications at this point.

As far the t-case tranny and axles go. I am confused about the front axle. What really has got me ocnfused is the whole fulltime or locking hubs 4x4. If this could be explained....Like I do not even know how to explain my confusion..

I mean I was just going to use the NP231 or NP241 4x4 t-case and mate that to a Ford 9" and a Ford/Jeep Dana 44 front.
 
IcedXJ said:
Like I do not even know how to explain my confusion..

I mean I was just going to use the NP231 or NP241 4x4 t-case and mate that to a Ford 9" and a Ford/Jeep Dana 44 front.
Click to expand...

I think the S-10s had the 700R4s and the Np231 T-case and had the 4.3L V6 with the higher stall.

The NP241 is junk IMO, it has a differential meaning one wheel drive enve when its in 4 wheel drive, one rear tire is in a hold all the power from teh front axle goes to the rear and to the tire in the hole (open differentials at the axles, and a differential at the T-case)

The 231 is nice because when in 4wd the frotn and rear drive shafts are locked together, but by a chain, The Chain makes it a weak design compared to gear drive t-cases like the D20, d300, and NP205. I would suggest using a d300 for your project and flip it to Drivers side drop. Thats alot more work then just a NP231 from an S-10.

The axle lockouts does not really matter, Just means when in 2wd your front drive shaft will spin all the time more weigth more friction. newer stock XJs are like that. Hubs are nice but when you abuse them they are a failure point over flanges (no hubs).
 
etaniyani said:
lol, the D35 isn't THAT bad, and is not going to break with stock engine and stock tires. i would think that because of all your power, you should be able to run a higher ratio like 4.10, but it depends on what tires you plan on in the future.
Click to expand...

what is wrong with you. other than a couple die hards, almost everybody hates the D35. my wife who doesn't go offroading nearly as much or as hard as me (she likes the gentle trail rides) broke her D35. with a stock 4.0L and 30" tires.

need more proof. go to google image search and type in: broken jeep axle

wow isn't that weird. it comes up with 9 pages of dana35. i find that interesting that D35's come up as the main problem when associating "broken axles" with "jeep".
 
I hate the Dana 35 and I am very suprised that it has not broken. I mean I am pretty sure that I have a Dana 35 and not a 44. Even though my Jeep falls in that year range for the 44, but I also read the gas tank has a higher capacity for the Tow Package and I have about 16-17 gallon capacity.
 
ttu.or said:
......as far as gear ratio goes if you have a good 350 to something healthy dont gear overly high. 4.10's and 33 will scream on the road.......
Click to expand...

How do you figure that 4.10 will scream on the freeway? What do we go to when we regear our 4.0L's?? 4.56, 4.88.

The 700R4 has a better overdrive ratio than the AX15 and the AW4 with a .70 OD. Yes the 350 will have better torque than a 4.0L anyday, but a 4.56 gearing with 33's will be just about right. The 700R4 has a 3.06 first gear, worse than the AX15 which has 3.83, but slightly better than the AW4 which has 2.80. Your RPM's in OD with 4.56 gearing will be 2200 at 65, NOT screaming at all. 4.88's will put you about 2400rpm's at 65. 4.10 will be about 2000rpm's.


The NP231J should be the same as the NP231C in gearing as far as LO goes.

Its recommended most of the time that 5spd Heeps w/ 4.0's regear to 4.56 with 33's, and 4.88 for auto's.

If better gas mileage is another thing your looking at, then get 4.10's or a Geo Metro.

This website has a great way to determine what your rpm's will be at at any given speed. Just enter your tranny gear ratio and rear end ratio, then tire size and redline, your good to go.

RPM caculator
 
scorpio_vette said:
what is wrong with you. other than a couple die hards, almost everybody hates the D35. my wife who doesn't go offroading nearly as much or as hard as me (she likes the gentle trail rides) broke her D35. with a stock 4.0L and 30" tires.

need more proof. go to google image search and type in: broken jeep axle

wow isn't that weird. it comes up with 9 pages of dana35. i find that interesting that D35's come up as the main problem when associating "broken axles" with "jeep".
Click to expand...

Ever think that broken 35's are so common because 35's are so common? Not that I'm saying you should ever put a 35 behind a V8, they really aren't that bad. Not everyone "hates" the 35, those of us who really know recognize it as a good axle as long as you don't overly abuse it. Hell, I do abuse them and I still can't break one.
 
in gearing on a v8 it is a whole different animal. comparing a 4.0 to a 350 is like comparing a mild 350 to a mild 454. or in jeep terms a 2.5 to a 4.0. if im wrong you tell any one with a 2.5 to put 4.56 with 31's and 4.88's with 33's, and where are the rpms on that. on a small block with 32 in a stock chevy z71 the factory puts 3.42 and 3.73 gears in a truck alot heavier than a xj. and the half ton truck has a half ton tow rating and they arnt a slouch with 3.73 gears and 32's. i run a actual truck with 4.10 gears a stock 350 and a 4l60e. it has plenty of power cruses great on the hiway and does as great as a ifs truck can do off road. btw i have a np241 t case which has the same low range as the np231. a built 350 has excelent torque between 1800-2000 rpms. if you are going to eventually go bigger than a 35 to say a 37 or bigger then id think about 4.56.
 
Well I was thinking that I am going to have to match gear ratios for front and rear. Since I am keeping the Dana 30 for the front and going with a Ford 9" in the rear I am going to stick with the stock ratios. Which is where I am unsure of what they are. I have the 1989 Jeep Cherokee Limited 4.0L. I do not think it has the tow package, but I am not sure how to tell. If it does not I believe the ratio is 3.53 or something like that and if it is I think it is 3.73.
 
etaniyani said:
lol, the D35 isn't THAT bad, and is not going to break with stock engine and stock tires. i would think that because of all your power, you should be able to run a higher ratio like 4.10, but it depends on what tires you plan on in the future.
Click to expand...

My brother broke a D35 in a stock 4.0 YJ with stock tires. Blech.
 
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