'64 rear end swap out

[Wildcats_95]

Ok, I looked over the FAQ before posting and didn't see this one yet...but I am sure it is there. I am replacing the inline 6 in my 64 C10 with a 350 engine and 700R4 transmission (original I know). Was talking with a guy at the shop today who said I would probably have to replace the rear end. How hard would it be to swap out the original and put in a Ford 9 inch? What measurements do I need to make sure of before proceeding? Thanks in advance, and yes, I know I don't know a lot about this stuff...just learning as I go along.

[NorthstarGMC]

You'll have to shorten it and get a custom driveshaft.

You'll need to move the mounting plates for the u-bolts and line up the diff angle to the trans.

It can be done, but it's not just a bolt up job. I've read about a lot of people bolting up S-10 rear ends easily. Search the forums for S-10 rear ends.

[Captainfab]

I see absolutely no reason to change the rear end in your truck. What you have is a truck 12 bolt, and as long as it is in good condition, you're not going to tear it up. That same rear end was used up thru '82 in the C10's, and thru '79 in the K10's, behind big blocks as well as 6 cyl's. If the gear ratio is an question, you have a 700R4, so it should be just fine.

If you insist you need a 9 inch, that will require shortening a housing, custom aftermarket axles, welding on trailing arm mounts, fabricating a panhard bar mount, etc. Plus a good bit of money.

[blackedoutharley]

Originally Posted by Captainfab

I see absolutely no reason to change the rear end in your truck. What you have is a truck 12 bolt, and as long as it is in good condition, you're not going to tear it up.

^^^^ THIS!

I would rather have a worn out 12 bolt before I would ever consider a rear end from an S-10 (of all things).

[NorthstarGMC]

Originally Posted by blackedoutharley

I would rather have a worn out 12 bolt before I would ever consider a rear end from an S-10 (of all things).

How about a 14 bolt posi? Anyone have some 8 lug steelies?

[J.Cagle]

what rear end does an 84 suburban have? Are they ok to use?

[brokenspoke]

Originally Posted by J.Cagle

what rear end does an 84 suburban have? Are they ok to use?

They are wider

[fleetsidelarry]

Originally Posted by Wildcats_95

... Was talking with a guy at the shop today who said I would probably have to replace the rear end...

Just curious: did the guy say why? was he thinking the 6 cylinder rear was weaker than those that came with the V-8s?

[Wildcats_95]

Thanks all! The guy was saying it would be an issue because the 6 cylinder was weaker than the 350. I posted this because my intention was to just keep the original rear end but thought this guy might know something I didn't. But thanks to you all, I will continue with my original plan. @Captainfab -- I was thinking that going to the 700R4 was a pretty good combination with the existing rear end...thanks for the confirmation.

Really appreciate all the advice...Thank you

Dave

[Captainfab]

An '84 Suburban, assuming it is a 1/2 ton, will have the 8.5" 10 bolt. And yes they are wider....1-1/2" wider than the '63 to early '70 rear ends. The 8.5" 10 bolts are plenty good for a lot of applications. They are stronger than most people give them credit for

Originally Posted by J.Cagle

what rear end does an 84 suburban have? Are they ok to use?

Originally Posted by brokenspoke

They are wider

[blackedoutharley]

The rear ends were the same 12 bolt to 12 bolt regardless of the engine... I would certainly suggest servicing it with fresh oil as a minimum though

[fryer1979]

Originally Posted by Captainfab

I see absolutely no reason to change the rear end in your truck. What you have is a truck 12 bolt, and as long as it is in good condition, you're not going to tear it up. That same rear end was used up thru '82 in the C10's, and thru '79 in the K10's, behind big blocks as well as 6 cyl's. If the gear ratio is an question, you have a 700R4, so it should be just fine.

If you insist you need a 9 inch, that will require shortening a housing, custom aftermarket axles, welding on trailing arm mounts, fabricating a panhard bar mount, etc. Plus a good bit of money.

Man this guy is quick!

That's about what I was going to say.

[Budman56]

Originally Posted by Wildcats_95

Thanks all! The guy was saying it would be an issue because the 6 cylinder was weaker than the 350. I posted this because my intention was to just keep the original rear end but thought this guy might know something I didn't. But thanks to you all, I will continue with my original plan. @Captainfab -- I was thinking that going to the 700R4 was a pretty good combination with the existing rear end...thanks for the confirmation.

Really appreciate all the advice...Thank you

Dave

WILDCATS
I did change the axle and it wasnt too hard to do but there is work to be done, you either have to buy the brackets to weld onto your doner axle or cut the ones off your old alxe. here are some photo's of when I did mine, also I installed a 700r4 trans with the doner alxe from 1990 c20 dana 70 with 373 gears. Captian fab and all the other guys in this forum have most of the info you will need to do the swap if thats what you wind up doing in the end. my swap only took the weekend to complete.

[chevyrestoguy]

I am in the middle of doing this swap as well, and Budman56 summed it up exactly.

[Wildcats_95]

@Budman -- Thanks for the advice and posting the pics. That is a very nice set up you have there. I think I will stick with the original rear end. I might bug you later to see what you needed to do for the crossmember for the 700R4. Looks like the engine bolts right up to existing engine mounts.

Thanks again all for the help.