55 series 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

charlieo · 02-01-2004, 03:03 PM

My Father-in-law has a 55 series 2 chevy truck . It has the original rear end but the ratio is too low (4:10 or 4:56) are there any gears avail ( 3:73-3:54) . Or would it be better to just change the complete rear out to a Ford 9" or the gm 12 bolt ? Would one of these bolt right in ?

rico_bob · 02-09-2004, 03:44 PM

3.38:1 Ring and Pinion Gears that fit the stock 55-62 Chevy Pickup differential case are available from Patrick's in Casa Grande, AZ. In his catalog Pat lists them as: complete kit (with axle bearings) for $200, and a Lite Kit (nix the bearings) for $115.00 web: www.patricksantiquecars.com

If you are going to street rod your 55 then you may want to look for a Camaro Nova or other rear end. Best to study lots of articles on what others are doing and make a plan! AND make a budget! My two cents worth, rico_bob

greatdaen · 02-09-2004, 07:02 PM

Chances are that if you change to a different rear axle, you'll have to weld on spring perches. I think all the 10/12-bolts out of a GM car will have coil spring pockets. The chances of a truck 10/12-bolt having the perches at the correct location, with a correct mating profile AND that place the pinion at the correct angle are going to be rare. Same issues with the Ford rear axle.

If you do swap axles, it is pretty straight forward to have someone either fabricate new perches or salvage the old perches off your removed axle. The welding is straight forward too - for someone that knows how to weld. Even your average Joe can bolt it all together before welding to ensure everything is located properly. But you need to orient the axle to the spring perches so that the angle of the pinion shaft axis matches the angle of the transmission output shaft axis. Again, not hard if you know what to do.

I know, because I did it wrong myself. The fix - short of cutting the perches back off and rewelding, was to have some wedges made at a machine shop that bolt in between the spring and the perch and correct the angle.

After all the monkeying around, it would have been much cheaper to pay someone the first time around.

-dch

BEAVIS · 03-04-2004, 02:31 AM

My Dad owns that same truck and it has a GM 8.5 posi under it. The truck had that rear under it when we bought it, as far as I know the perches were not relocated but I could be wrong. My suggestion would be to find a 70-81 TA or Z28 with the factory posi rear end and use it. Those cars are still around, I recently passed up an 81 Turbo TA w/ a disc brake posi complete car for $300. This would be your best bet since these cars are leaf spring. Hope this helps.

02-01-2004, 03:03 PM	#1
charlieo Registered User Join Date: Feb 2003 Location: sw Posts: 341	55 series 2 My Father-in-law has a 55 series 2 chevy truck . It has the original rear end but the ratio is too low (4:10 or 4:56) are there any gears avail ( 3:73-3:54) . Or would it be better to just change the complete rear out to a Ford 9" or the gm 12 bolt ? Would one of these bolt right in ?

02-09-2004, 03:44 PM	#2
rico_bob "Treasure the Ride" Join Date: Nov 2001 Location: Mid Michigan, Harrison Michigan, USA Posts: 682	High Speed Gears ? No Problem 3.38:1 Ring and Pinion Gears that fit the stock 55-62 Chevy Pickup differential case are available from Patrick's in Casa Grande, AZ. In his catalog Pat lists them as: complete kit (with axle bearings) for $200, and a Lite Kit (nix the bearings) for $115.00 web: www.patricksantiquecars.com If you are going to street rod your 55 then you may want to look for a Camaro Nova or other rear end. Best to study lots of articles on what others are doing and make a plan! AND make a budget! My two cents worth, rico_bob __________________ If you think you can you're right. If you think you can't you're still right. Trucks: '56 SWB; '57 SWB; '63 C-10 Current projects: 1963 Long Fleetside for the wife! '56 for the daughter. Visit us at: www.ricos-rods-and-relics.com Last edited by rico_bob; 02-09-2004 at 03:46 PM.

02-09-2004, 07:02 PM	#3
greatdaen Registered User Join Date: Feb 2004 Location: Apache Junction, AZ Posts: 102	Chances are that if you change to a different rear axle, you'll have to weld on spring perches. I think all the 10/12-bolts out of a GM car will have coil spring pockets. The chances of a truck 10/12-bolt having the perches at the correct location, with a correct mating profile AND that place the pinion at the correct angle are going to be rare. Same issues with the Ford rear axle. If you do swap axles, it is pretty straight forward to have someone either fabricate new perches or salvage the old perches off your removed axle. The welding is straight forward too - for someone that knows how to weld. Even your average Joe can bolt it all together before welding to ensure everything is located properly. But you need to orient the axle to the spring perches so that the angle of the pinion shaft axis matches the angle of the transmission output shaft axis. Again, not hard if you know what to do. I know, because I did it wrong myself. The fix - short of cutting the perches back off and rewelding, was to have some wedges made at a machine shop that bolt in between the spring and the perch and correct the angle. After all the monkeying around, it would have been much cheaper to pay someone the first time around. -dch

03-04-2004, 02:31 AM	#4
BEAVIS Registered User Join Date: Jun 2001 Location: Paris,Texas Posts: 35	My Dad owns that same truck and it has a GM 8.5 posi under it. The truck had that rear under it when we bought it, as far as I know the perches were not relocated but I could be wrong. My suggestion would be to find a 70-81 TA or Z28 with the factory posi rear end and use it. Those cars are still around, I recently passed up an 81 Turbo TA w/ a disc brake posi complete car for $300. This would be your best bet since these cars are leaf spring. Hope this helps.



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