So I've had this B&M Holeshot, 2,000 rpm Stall, Torque Converter for about fifteen years now... Just been sitting on the shelf, thinkin bout stuff. Kind of curious if it'd be worth the trouble to slip it into my Formula. It's a B&M 70417, they're kinda proud of it... Says 1900-2100rpm stall. The car is what most would consider stock, engine is original, little porting on the TPI, the usual suspension mods... So what say the experts? Worth the trouble to drop it in, or trade it for something I can use?

 

It depends on what you are thinking of trading for. If I had one sitting around right now, it would be installed this weekend. Even on a stock car. Stock converters are a compromise for mileage and performance. You will retain the lockup capability so that is a wash. It will get you in the power off the line and keep you in the power during shifts.

 

Put it in. Higher stall = good. Mine has a 3000 stall in it and I love it.

I don't see a downside. Unless it doesn't work.

GD

 

Guess my thought was always that 1900-2100 isn't enough better than stock to worry about. It got lost in the mayhem of multiple project cars it could potentially go in, that ultimately led to being shelved until I decided where I was going. Since the sole 700R4 candidate was slated for a T56, it really didn't make any sense to put the torque converter in, but now the T56 is headed for the other Firebird, and the Formula is going to stay 700R4 for the foreseeable future...

Has anyone run one of these B&M converters? Curious how much difference it makes on a 350TPI car.

 

What IS the stall on a stock TPI torque converter, Drew? This does sound like a very small RPM difference, as I would "guess" stock is 1800-ish.

 

I think the lowest number I've seen associated with the stock converter is around 1700rpm? Maybe someone else can better answer that question. But I suppose it varies depending on factors like vehicle weight, power, torque curve, etc... Idk, just guessing really. If it were rated a few hundred rpm higher, I probably already would have tried it.

I need to get the 700R4 in the car rebuilt anyway, it has some nasty habits and I've been limping it along for 20 years. Probably about time I pull it out and get it rebuilt with the usual upgrades. As long as it's out, might as well change the converter... But then might as well go higher stall... Kind of a moot point, I suppose, since I have a line of other projects in front of tearing into a car that currently drives. Just had to move the B&M the other day to get in a box of 700R4 parts and started thinking about it again.

 

You have the shell upgrade for your planetary or is it what it came with still?"

 

The transmission in the car should all be original 1991 parts. I know there are internal issues with the transmission I need to address. For awhile reverse went wonky, and neutral was a forward gear. Park would have been a forward gear too, aside from the parking pawl engaging. I suppose I should really pull the trans and haul it in for a rebuild, but it mostly responds normally if I don't drive it like I stole it.

 

Stock TPI converters are 1300-1700 depending on engine and RPOs.

I dropped a 2200 in my otherwise stock 305 TPI Iroc. Made a huge difference in 'fun'. Give it some gas and she spins up and jumps. Major butt dyno kick.

If you have a 'free' 2200 sitting around and can swap it easy. it's well well worth it.

I'm running a Daaco, not a B&M, so I'm speaking toward stall speed, not the specific converter.

 

And that B&M should stall at 2100+ in the 5.7.

 

If your current transmission has problems, wait until they are fixed until you use that converter
so you do not contaminate it.

 

Good point. Hard to flush a converter.

 

The B&M torque converters are not very good to start with. Their history on TC's is not very good. The oem Corvette TC's are a good one. I think the oem V-6 TC's are a higher stall too.