Howdy! I have a '55 1st series 3100, and am considering changing to 3.55 gears. It is a torque tube set up. I was reading an article on Deve's Tech site, which states that 1954 carrier assemblies are different, and would require transplant of an older carrier assembly in order to use the new gears. My question then is: does anyone know how to identify the newer style carrier, so I can determine if I need to search for another carrier assembly or not? Thanks!
A 1955 1st series 3100 has an open driveshaft. A 1954 and older 3100 has a closed driveshaft or torque tube. My 1955 1st happens to be up on jackstands and I verified that mine is stamped N K 1004. Look on the front of the rear axle, passenger side and at about 8 to 10 o'clock, there may be hand-stamped letters and numbers. Cheverolet 1955 Specifications-Truck------Serial Numbers-----page 63 N = 1955 (J=52, L=53 etc.) K = Factory location (K = Buffalo NY) 10 = October (Sept = 9 etc.) 04 = 4th day of the month
Deve's website said the torque tube for the 54 is different bolt-wise than previous years.
Setting NEW gears to mesh well is very important and if you lack the skill, I suggest searching for a rear axle shop near you.
Deep pockets are needed to purchase carrier/pinion and other bearings. Factor that in if you also plan to go with a non-stock transmission i.e. S10 5 speed.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Thanks for the info, I shall check that. The title and serial tag of my truck show it to be a '55 1st series, but it does indeed have a torque tube driveline, which causes me to wonder if the rear was changed at some point (unlikely as the transmission would also have needed to be changed and the truck has other '54 features as well), the title and serial were changed (also not the most likely due to the condition of the door tag, with factory rivets, etc) or its being built very early in the model year with some '54 parts. Thanks for the reminder on the importance of proper gear mesh, I have rebuilt many rearends, though have not rebuilt any chevy rears as yet. The truck is running a SM420 transmission, which I intend to keep.
I've seen a 1951 titled as a 1952 and it was legit. The truck was built in 1951 and sold new in 1952. Dealers can't do that today. The side hood emblems are different (54 and 55). Block casting year (covered by the starter), head casting year (underneath rocker/valve cover) and engine serial number year. You want to keep good records of what you find in case you want resale in the future. FYI: https://www.motortrend.com/how-to/1003clt-chevs-of-the-40s-3-55-1-ring-and-pinion-swap/ click on see all 32 photos.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
The SM420 can be converted to open driveline configuration with nothing but a rear bearing retainer and output yoke change- - - - -lots less cost and effort than the ring & pinion swap to the torque tube rear axle. Once that's done, there's an almost unlimited choice of open driveline rear axles to pick from, with a wide variety of gear ratios. If you want to keep the six lug wheels, look for certain years of S-10 4X4 axles, or any of several models of Japanese pickups and Toyota Land Cruisers. Jerry
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