Will adding a shift kit to a BB trans mess with its ability to downshift to 1st from 30mph, like it's said to be capable of doing? I've never driven a true stage 1 car with a BB so I really want it to be as authentic feeling as possible
Ethan, read through this article, http://www.buickperformanceclub.com/SPTrans.htm While it deals with the switch pitch, there is a section there that explains why the BB does what it does. I say a shift kit won't hurt that ability since it really is a valve body calibration not effected by a shift kit.
Hugger what shift kit are you looking to do........if you just want to firm up the shifts some and shift a little quicker, that can all be done with just drilling a few holes in the spacer plate and removing a few springs. Is the transfer all apart or together.....if apart I would highly recommend dual feeding the direct drum. It's as simple as removing a seal ring front the center spirt and adding a freeze plug cup next to the center support bolt.......this will double the holding power of 3rd gear. I will be gone for weekend and might not be able to get you the info during those times......but you have my number I will be more than glad to walk you through some basic improvements that should effect any calibration, we are just opening up oil flow passages and removing cushion spring in the accumulators. If you don't have the number still just pm me
It shouldn't so long as the 1-2 modulator valves and 1-2 accumulator valves/springs have not been replaced or modified. But a kit may make the shifts excessively firm. The BB trans shifts pretty firm without valve body modification. I know of one '70 Stage 1 car with a Trans-Go shift kit installed in it's original BB trans, and an audible bang occurs on shifts. It hits so hard that the inside rear view mirror will vibrate even on part throttle shifts. I would recommend trying it in stock form first, and see how it feels to you.
That's just it , ive always heard the BB snaps pretty good, this is going in my 70 X driver car, maybe 425hp at best but I do want a nice snappy shift, haven't had a trans that shifted snappy in forever since I run big stalls and they soak up the shift so much, plus with decent HP you don't want a hard shift just a quick shift. But anyway i was wanting to maybe build this one since it's a budget build , just do the trans go kit , I've used it several times on customer cars. The dual feed drum mod sounds like a nobrainer , I know the trans in my Orange Car has it.
The OW (same as a BB) in my 71 Stage 1 was great. At part throttle at shifted nice & smooth but at WOT it hit second hard! It would leave about 10-15 feet of black marks on the 1-2 shift. And this was with the stock engine (just a re-curved distributor).
