What's the difference between the SBB and BBB transmission cross member configuration and mounting hardware for my '72 Skylark Convertible? The original cross member in my Skylark Custom 350 is a stamped-steel (sort of an inverted U cross section) affair that's sandwiched between rubber isolators that are clamped to the frame rails. That is, the ends are not bolted directly to the frame. The car will soon be receiving a Tri-Shield 482. Although no sanctioned drag strip activities are planned for it, I'm still concerned the X-member to frame mounting points (especially) won't be strong enough. I'm also wondering if the X-member ridged enough. So, what X-member upgrades, if any, are necessary? Thank you in advance for your inputs.
That's the way my cross member is attached. It's been that way since I bought the car in 1999, through the 13's, 12's, and now the 11's.
Pontiac Grand Prix uses a boxed frame and same length cross member as an “a” body convertible. The Trans cross member is reinforced as well. I have one in storage and can post a pic sometime Monday
Had time to pull the Pontiac x member today. I bought this to replace my factory Buick piece that had a rusted tab where it inserts to the rubber block. I was told they reinforced them for use in the early model grand prix’s with the 400/400 motor trans combo. Pretty amateur job of welding from the factory It is the same length as the convertible piece as Pontiac Used a boxed frame on some of those models
Thank you Larry and 2dtrak. I was kind of concerned about it when I saw the "1968-72 Convertible crossmember" ad in the "Parts for sale" forum this morning. That particular crossmember was original equipment in a '71 Grand Prix. I've always looked at the crossmember-to-frame mounting with suspicion, though. I suspect that it helps reduce vibration and noise a little. I just wasn't sure about strength. Sounds like I shouldn't worry about it. Thanks again you guys.
To answer your original question, the only difference between SBB and BBB is the oval slot for the e-brake cable on BBB. The Olds crossmembers are similar to Buick but bolt directly to the frame. I'll post a picture of one later.
