Originally Posted by Blusmbl
Originally Posted by an8sec70cuda
[quote=Blusmbl]Nick...my 727 is still living, but I don't race my car very often. I killed a sprag a few years ago that took out the case. It let go mid wheelie in 1st gear, crunched the oil pan, but drove back in the trailer.
It still has stock shafts in it, but it wouldn't surprise me if it broke one on its next pass.
I have a 5 pinion steel planet, billet steel drum, non LBA Turbo Action transbrake, deep cast aluminum pan, etc. Nothing real fancy.
My car will go 8.60s, but my best 60' is a 1.30 (may not have tripped the beam w/ the front tire?).There's a fine line b/t wheel spin and wheel stand w/ my combo.


That's helpful too, thanks Chip! I'm heavier but am definitely going to be making less power and torque than you.

Do you normally run your car at the track on slicks or the radials?

And one other question, is the LBA stronger for situations like those, or would the sprag have failed anyway even with a LBA valve body?


Yes LBA is the safest way to go to protect the sprag. Period. All the load is on that sprag in first gear. No matter if you have a bolt in 16 element or not, it can still fail. So if it fails, it’s only in first gear because the sprag is holding the low reverse drum from spinning counter clockwise then once you shift into second gear the sprag begins to overrun, hence the term overrunning clutch. So the L/R drum begins to spin clockwise freely in 2nd and 3rd gear with no load on the sprag. The low band apply protects the sprag so now the L/R band is helping dampen the load the sprag sees in 1st gear.

Last edited by 71Demon528; 04/20/24 01:29 PM.