Currently foot braking and finding that tel:2000-2500" rel="nofollow - 2000-2500 is about the limit for holding it on the line and getting off the line relatively consistently. Any more and it really loads the suspension up, leaf springs and slapper bars, which tends to result in wheel spin. The convertor will hold maybe 3500 stall on the brake and flashes to around 4400 when launching.

I'm a bit of an online calculator fan and based on my latest run at 119.3 mph, I should be able to pick up a couple of tenths in the 1/4 mile if I can knock a tenth off my 60' time, which is currently around 1.65, Wallace is giving me me an ideal 60' of 1.54.

Also looking at doing a bit more bracket racing next season, so I'll need to be a lot sharper on reaction times. I'm slowly getting a little better at this, but the guys I'll be racing against are pretty sharp and it would be nice to be able to go a few rounds since we run knockout eliminations.

I gather a transbrake will help with both of these ambitions, however I know it will potentially put a lot more stress on the driveline. Realistically, what needs to be done to the 727 transmission to make it live with a transbrake and what about the rest of the driveline? 

 

A 727 rebuild with good clutches is all I feel you'll need at your power level.

What will you need? Having blown out a driveshaft at 120 mph I tend to lean on the bullet proofing concept anymore.

I run 1350 U-joints, a billet transmission yoke, and a billet rearend yoke.

Also if you don't already have it stepping up to a 20,000 pound rated transmission cooler is a must.

Once you put it on the brake the transmission temperature starts soaring quickly and can get 300 degrees in no time if you don't have a proper cooler.

Tom

I’m thinking I would be able to launch at a little higher RPM and maybe pick up a little in the 60’, maybe a couple of tenths over the 1/4 mile, not expecting to pick up half a second or anything crazy like that. 

Consistency and better reaction time would certainly help with bracket racing. At the moment I mostly run off street meets which are essentially test and tune, you are mostly racing heads up with the car in the other lane but not matched up into any sort of competitive format, so you might be up against a 16 second car or a 9 second car. They do run a best package competition for a bit of extra interest, person with the best combination of reaction time and closest to dial in wins a free ticket for next week.

At the moment it costs me $70 to enter and I might get 8 to 12 runs in a night, if I step up to the main events it’s $195, you get 3 qualifying runs and then it’s knock out eliminations, so might only get 4 runs if you get knocked out in the first run. Eliminations are seeded too, so if you are a bit ordinary, you will get matched up with the better qualifiers.

So anyway, my 727 as it stands is pretty standard other than some performance frictions, a bolt in sprag, reverse pattern manual valve body and billet servo piston that was recommended with the valve body.

I could build a new transmission if I need to run things like a steel drum (sounds like that might be a good idea) or other aftermarket hard parts, would be replacing the valve body anyway. Might be a good time to look at a more serious race converter as well, since that would likely help too, can get something that is setup for the transbrake.

Probably wouldn’t hurt to put some new uni joints in. Does anybody make a billet yolk for the AMC20, assuming the AMC20 is up to it with a tru trac centre and Moser axles.

I did upgrade the transmission cooler recently, but might need to revisit that by the sounds of it.

I've seen it happen many time with non spooled cars.

PS: my CSR transmission shield is still sitting on the shelf, might be a good idea to install that if I don’t get a steel drum.

You already have the billet servo that is required. I run an early 5/16 rod rear servo.

I also run a billet aluminum drum. A billet front drum is highly suggested as well as a shield!

A low band apply brake v.b. like an A+A is also suggested.

This seems like a reasonable sort of list from the Moparts forum: