Well, I'm back in the shop with a goal to get my 1951 3100 on the road by June 2017. The dilemma that has me going into tangents is trying to decide which path to take for the running gear. Here are some specifics of what I have: 235 CI (Stock... I think) 4-speed, SM-420 (stock) Likely going to have 16" wheels Available rear ends that I have: 1955 Chevy pickup, outside width, 62", casting # 3707340, 10-bolt, 3.90:1 ratio, 6-lug 1968 Chevy Nova, 2.73:1 ratio, 5-lug Now for my question, which rear end would be best to use for leisure driving and periodic highway driving? I would like to cruise up to 70 MPH. Some folks suggest swapping out for a T5 tranny, but that can be pricey. I wanted to get some opinions from y'all on the easiest cost-efficient way to go. Thanks! Dan
Dan, I have found an engine with near identical horse power and torque as yours works fine with a 2.73 rear on Texas flat lands but not in the hills of Missouri. Cruises easily at 70 on flat ground. The 3.90 would be pushing to the max for sustained 70mph cruising. If your truck had a 3sp column shift then a Borgwarner overdrive is a direct bolt in giving a 2.70 final for cruising and a kick down for hills. Also the cheapest way out. When you bring up 70mph please spend money FIRST on updated brakes.
Coilover - Thanks for the feedback. Just curious, do you have the the 4-speed on the floor (w/first gear granny)? Oh yes, I'm definitely upgrading the brakes. Plan on front discs, drum in the rear. Dan
No, had a three speed on the column until my wife wanted to start driving and couldn't handle a standard shift. Then went with a three speed automatic and have the parts now to go to a 4.11 rear and a overdrive automatic that gives a 2.88 final drive. MUCH more than you care to do I'm sure but who can argue with the other half. We take really long trips and having something both can drive helps a bunch. You can get a ring and pinion for your Nova rear for under $200 in a very versatile 3.55 ratio. If you can install yourself it would be the cheapest way out
You're setup sounds nice, perfect compromise. I really like the idea of the ring and pinion swap, that is a reasonable price and something I can handle myself. Much appreciated!
I have a 3.55:1 rear gear, 1:1 high gear (a granny-low SM420) and 31" tall tires. 70 MPH continuous cruise is about as fast as the fairly stock 228 GMC six cylinder wants to run, with an occasional sprint to 75 mph.
Thank you Bill. I'm going to stick with the SM420 and go with the Nova rear end and swap out the ring and pinion as Evan suggested. It sounds like if I don't like it, there are various options for trying alternatives. Thank you. Dan
