Has anybody used the 727 second gear launch valve body with any luck and what brands.
thanks Tom

That's all I use... I think they call it a Powerglide

yep got one of those powerglides you speak of in the cuda just trying to turn my 727 in my belvedere into one

I have one of John Copes .
Works great and tamed down my car on the launch .
Since I started using it got my best 60 ft times.

Transact.

I may get one for my Challenger. I am going to test it with the 3 speed Torqueflite first to see how it does since I bring in more of the power with both kits after the launch anyway.

Backing off the spark can make it feel like you started in overdrive.
If that's what you want.

I need one of these 2nd gear transbrakes in a bad way.

I put one in my Dart because the local track doesn't prep well and radials don't hook there. Last fall it went 1.49 60' leaving in second, every attempt leaving in first off the brake resulted in tire spin.

So getting it to leave in 2nd with a 1.45:1 gear ratio and still 60’ is all about the converter I’m guessing? Probably need big power for it to be effective as well? Would it not be just as effective to use a higher rear gear and have 1:1 for better cruising rpm?
I remember Freigburger at Hot Rod (I think) did a big converter/gear ratio round up using a Nova with a 572 crate engine (the race one) and a crate LS something or other and the take away was the more power/converter you have, the less rear gear ratio matters. I tried looking for the article but I can’t find it.
I also remember reading of a members experience here (can’t remember his name, his avatar is the guy running with a pair of scissors lol, I think he might own the Brown Sugar Barracuda) where he had a BB Mopar in an early (I think) B body. High stall TC and 4.30 gears. Blew the 4.30’s and put a 2.94 in it to just get by and ran the same basic et.......

I had a number of transmissions and low gear sets in my car, from 1.76 to 2.74. Sometimes just to answer the question, "what if". As a result, I've come to appreciate the importance of SLR on the performance of a racecar, and all the factors that play into that tuning decision. Missing the optimum deal by a few tenths of a point in ratio can be the difference between the car being fast and consistent or being a turd.

2nd gear launch sure provides a bigger tuning window on the launch that's for sure. It's just another way to manage torque at the tire rather then do it through engine power management.

If you're in a situation where you are still knocking power out of it 30 or 40 ft out, you obviously don't need the 2.45 ratio. If you are only knocking power out of it for the first 0.3 sec, then the 2.45 will still be quicker.

I know mines not a world beater, but through a lot of suspension trial and error mine will leave on 4200rpm @14psi of boost. It's at 5200rpm and 23psi within 0.3 sec. A lot of it is just getting the tire planted and making it through that first tire rotation then you can really pour the power to it.

I think I would invest into the grid.. there's a lot you can do with timing.. for instance this past weekend we were leaving the starting line at 23 degrees of timing and bringing the timing back gradually over 2 seconds.. this allowed me to run low 1.20s 60 foots on a small Tire with no wheelie bar
.. take a peek at the rules for your particular class and see if the grid would be legal...

Wrong again

For sure knocking lead out of it will kill torque. It's also nice because you can have full control of when/how fast it comes back in.

Not to derail the thread but...


It's not quite that simple. The thing is especially in an automatic car, making torque gets the car up to a higher flash stall on the converter. The gain in RPM air flow is a MUCH better way to spool the turbo then through retarding the timing. Retarding the timing can work good once you start to get the turbo lit through full timing/RPM/High Stall speed, but if you roll in with low timing you'll have a hard time getting the turbo lit at all (unless you're talking a clutch car where you can make a lot of RPM without any load).




I had heard that ol' tale before too. I tried it on a 11 second 340 with zero sucess years ago. However what I found out later was that they didn't retard timing in high gear to gain MPH by itself... what it does is allow you to run MORE timing through the first 2 gears. The lower load of the first two gears will take/wants more timing, but it won't tolerate that at high loads in high gear. So you run more total for the first few gears, and then retard back to your normal best MPH timing in high gear.

That being said... I'm pretty sure we're not talking about cars still running points... lol

No, but 40 years ago I made a new plate to mount 2 pickups inside of a breakerless distributer. I had them offset enough to use as a start retard in a locked distributer. Used a double pole double throw switch to select which pickup was active. It worked great. Could have easily made one with only a few degrees timing difference for a high gear retard.

It just occured to me that one side of my switch was labeled START and the other side was labeled GOMANGO.

Just for fun: why don't some of you point out where I'm wrong BEFORE I waste me time?

Thanks everyone for your replies I guess timing is a good option I was just thinking 1st gear leave on a good track 2nd gear leave on a marginal track seamed like a no brainer. Jstinp61 what brake are you using?