hey guys, Does anyone know how strong 1949 Buick rear ends are? I'm building a 30 ford coupe with a 1949 Buick rear end. It all looks to be in good shape has 3.90ish gears. The cars an old school hotrod and used to run and drive with a flathead in the early 60s. when I got the car it had no engine or trans in it. It now has a relatively healthy small block and a 4speed. does anyone know if the rear end can take any abuse? I plan to bring it to the antique nationals and race it a bit. someone, please school me. I do not care if I blow it up, but I want to make at least one pass.
pictures of the rear end? I though Buicks were torque tube back then? Olds and Pontiac were different from Buicks, so saying BOP kind of doesn't make any sense, until the mid 60s, when they started using some of the same parts.
Yep, I am wondering about the origin of the rearend you have. Squirrel is, of course , correct. '49 Buick rear ends were born as torque tube types. But then again, so were Fords and Chevys, so maybe Buick is what you have. But, if so, what transmission do you have connected between it and the 'small block'? If you have a Pontiac or Olds rear end from '49, they are decent rear ends, but not as strong as the '57-'64 versions, but in a light car like your Model A, probably strong enough. Pictures??
Here's the OEM from my 46 Olds for comparison, what's the bolt pattern? I can't recall the OEM bolt pattern, 5 on 5 I think however driver's side axle studs were LH thread? I have a restorer friend who used the pumpkin from a local 49 Pontiac in his 46 Olds housing, a very similar housing to OEM Pontiac and a direct bolt in. Ratios were something like 3.9:1 or 4.11:1 with coarse spline axles, not a performance rear end however in a light car your may be lucky for a brief period of time until you side step the clutch!. Note that the early style pinion (companion) flange is different to the larger later model style. Inside C-Clip style to Wing style u-joint with step or recess in flange to accept joint. This is the later, bigger and stronger 57 - 64 rear axle with different pinion flange and larger axles. Be gentle or this could happen.
Wheel bolt pattern is 5 on 5" for BOP from the '30s thru '76 full size models and thereafter on most of the larger chassis rear drive cars.
You do not state if it was from the Special or the larger more powerful Roadmaster. All Buicks were large, powerful cars with straight eight engines. They would have a strong rear axle, stronger than a Ford or Chev. I don't think you will have any problems in normal driving. If you want to drag race, drop the clutch and burn rubber from every stop light that is different. But even then it should last for a while.
All of you are totally right I mis spoke, I meant to say 49 olds rear end. it does have a 3.91 ratio just re checked it, and is 5 on 5 bolt pattern. I can take more photos tomorrow when I’m back underneath the car making break lines. The engine is a good running Chevy 350 with a pretty healthy cam should make 400ish at the crank hopefully This is the style of u joint on the yoke. EVERYONE THANK YOU FOR ALL THE HELP!! Love this community
That is exactly what I have and I do plant to just drive it out the first couple of passes until I decide to go for gusto and side step the clutch at 4,000ish rpm The car was running around with a flathead back in the 50’s so I know the rear end is strong enough for 100-120hp but I hope to make 4 times that
Stick shift, early rear, no posi , 4,000 launches = Bad idea. I won't even get into the side step the clutch nonsense.
The 8 3/4 ring and pinion are plenty strong but the rest is a 120 HP piece. The core diameter of the 10 spline axle is to small to take any real power,a stock 50 Olds would bend the housing and the U joint is to small. All this is fixable. A girdle welded across the back of the housing,57=8 Pontiac axles and side gears,and a 56 Pontiac U joint and you have a strong rear end.
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