68-72 HO52 Question

[Mapleleaf]

Sorry if this is in the wrong spot I’ll move it if it is. I’ve been told that a 68-72 4:10 pumpkin from a Eaton H052 or 72 will bolt into my 49 3600. I‘ve got 4:57’s now (and I actually have a spare one as well).

How hard is it to get a 4:10 H052 from a 67-72? How common were they? Did they come in particular models in that year or particular engine/tranny combos?

Are there any codes on the outside of the axle that give the ratio?

Any help appreciated – I’d like to do a swap in the spring if I can find the parts.

Again, if this is in the wrong forum I’ll move it.

[Livrat]

Yes an HO52/72 eaton will interchange from 1938 through 1972...
67-72 Chev trucks used them under alot of 3/4 tons and all 1 tons.. They are quite common and not in the "desirable list" I tend to toss them as they are heavy, pretty undestructable and difficult to get parts for (other than bearing and seals).. the most common ratio being 4:10 under the 3/4 tons, and ya never know under a 1 ton.. from 4:10 through 5:38..
The axle code is stamped onto the top of the pumpkin

[swamp rat]

I would say to keep your eye open in the parts threads and start asking there, but be prepared to pay for shipping costs. Ouch!

[special-K]

I think now that you know they are the same differential through all those years you'll find one pretty easily.If old trucks aren't too plentiful locally,check the guys who part trucks here on the site.I believe there are a couple 3/4t trucks being parted now.The drop-out differential (or chunk) is heavy,but you must weight the shipping against cost/effort to set up the rear if you choose to only buy a ring & pinion set.
I really like these rears and will run them as long as possible.I dig the fact that these trucks are connected through the rear (sounds funny...haha) to the proud line of GM trucks since 1938.There hasn't been a better rear made since...equal at best,but with more bulk.

[lilred67]

i have sent 3-4 of the ho52's to the junk yard. i have 2 more i need to get rid of. i would think with all the year's of trucks they fit, there would be a market for them!!!!lol

[sharpie1972]

I like the fact that they are a "drop out" rear end and can be changed quickly without setting up gears, plus they just look stout! Sharpie

[special-K]

A lot of parts/components get tossed for modern replacements only to cause regret in the future.If I had a dime for every tale of "I wish I had hung on to that" I'd be rich.All the motors tossed for a 350 replacements and now at car shows people just yawn when they see one and dream of seeing the motors they replaced...for example.

[Longhorn Man]

look for 350 with automatic trans... 4.10 was standard with that combo, both in the 20 and 30 series

[Mapleleaf]

Thanks folks I appreciate the response. I guess I have a couple of boat anchors with these 4:57's. LOL If anyone wants them they can have them.

I'll post a wanted ad over at the for sale section and keep looking locally. I'm heading down to NH in February and I'd like to find a pumpkin by then if shipping costs are not too crazy.

[raycow]

Originally Posted by Mapleleaf

I'll post a wanted ad over at the for sale section and keep looking locally. I'm heading down to NH in February and I'd like to find a pumpkin by then if shipping costs are not too crazy.

Halifax is a good-sized city. Have you exhausted all of the local salvage yards already? These rears are not particularly scarce.

Ray

[factorystock]

Originally Posted by Mapleleaf

How hard is it to get a 4:10 H052 from a 67-72? How common were they? Did they come in particular models in that year or particular engine/tranny combos?

Are there any codes on the outside of the axle that give the ratio?

This is exactly why a 4.10 pumpkin should never be tossed. It is the simplisit way to change out a 4.57 ratio on 48 thru 72 3/4 tons for a simple back yard mechanic. Just think who many people who own much earlier years where this ratio was never available. The 4.10 ratio first became an option in '63, but didn't get popular till around '69. Axle code method is difficult because it is barried under tons of gunk and codes change from year to year.As Longhornman said, look closely at 69 thru 72 3/4 tons with 350's and autos.

[swamp rat]

>>This is exactly why a 4.10 pumpkin should never be tossed.<<

I agree with that! even the brake parts too! I'm still running an HO52 and asside from the hard to find parts they are pretty bullett proof.

I was thinking of converting to 4:10's someday and would love to get my hands on a 4:10 pumpkin one of these days too........after i crawl my arse outta all the unexpected bills i just ate.