TH400 Shift kit and torque converter
Thread Starter
Instructor
Joined: Jan 2021
Posts: 134
Likes: 22
From: Houston, Texas
TH400 Shift kit and torque converter
My TH400 was cleaned up and resealed by a local shop. I'm putting in a B&M Shift Improver Kit and drain plug kit before reinstalling it. Not sure if I should go with the Heavy Duty level or the Street level. I want good firm shifts but not neck snapping shifts.
Also considering an aftermarket torque converter for a little more street fun. What stall would you recommend? Any specific make/model you recommend? I've had good luck with B&M products in the past, but open to other makes.
It's a 75 L48. Fresh engine with flat top pistons and a Comp 268H cam and stock rebuilt heads. 3.36 gears.
All input appreciated. Thanks in advance!
Also considering an aftermarket torque converter for a little more street fun. What stall would you recommend? Any specific make/model you recommend? I've had good luck with B&M products in the past, but open to other makes.
It's a 75 L48. Fresh engine with flat top pistons and a Comp 268H cam and stock rebuilt heads. 3.36 gears.
All input appreciated. Thanks in advance!
Le Mans Master
Joined: May 2007
Posts: 5,007
Likes: 1,114
From: North tonawanda NY
Its always been my impression that unless your using a larger cam that requires it, using a higher rpm stall makes the car less fun on the street while creating a lot of heat. But I could be off base here as ive only used the stock 1800rpm converter that came in my th400. The 268h is pretty mild with a power range starting at 1500rpm..
I went with street performance level on my 2004r build as it was explained to me If I truly wanted to use this as a cruiser the heavy duty kit would have drawbacks. I want the car to be responsive and quick but not unruly and uncomfortable either. I also went with a mild 1800-2200rpm stall but im curious what opinions other folks have on using a larger converter with a smaller cam. I am using a larger 276-284 cam but in a 406 and I think with the overdrive I dont want a converter with a lot of slipping at cruising rpms. Your situation will be different I think.
I went with street performance level on my 2004r build as it was explained to me If I truly wanted to use this as a cruiser the heavy duty kit would have drawbacks. I want the car to be responsive and quick but not unruly and uncomfortable either. I also went with a mild 1800-2200rpm stall but im curious what opinions other folks have on using a larger converter with a smaller cam. I am using a larger 276-284 cam but in a 406 and I think with the overdrive I dont want a converter with a lot of slipping at cruising rpms. Your situation will be different I think.
Last edited by augiedoggy; May 31, 2024 at 04:33 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Actually, of all the automatics I have owned, my current 3,000 stall is absolutely the most fun on the street.
Higher stall converters are torque multipliers. If you have 300 horse at the flywheel, it will feel like 500.
I don't see any heat issues. However, for longevity of the tranny, I have added a B&M cooler in front of the A/C condenser.
Ironically, that remote addition lowered my water temps by ten degrees (190 > 180)
B&M shift kit is a wonderful addition to any auto. You can hold the engine in any gear, any RPM w/o up shifts. There is absolutely no pause up shifting.
(all my down-shift hardware has been removed)
What ever converter you end up with, it should be in the $400+ range for quality & durability.
I have the B&M Holeshot, 3,000 stall. (284 D cam and 4:11s rear)
Higher stall converters are torque multipliers. If you have 300 horse at the flywheel, it will feel like 500.
I don't see any heat issues. However, for longevity of the tranny, I have added a B&M cooler in front of the A/C condenser.
Ironically, that remote addition lowered my water temps by ten degrees (190 > 180)
B&M shift kit is a wonderful addition to any auto. You can hold the engine in any gear, any RPM w/o up shifts. There is absolutely no pause up shifting.
(all my down-shift hardware has been removed)
What ever converter you end up with, it should be in the $400+ range for quality & durability.
I have the B&M Holeshot, 3,000 stall. (284 D cam and 4:11s rear)
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
Race Director
Joined: Jan 2007
Posts: 10,643
Likes: 695
From: Danville Illinois
2025 Corvette of the Year Finalist - Modified
2024 C3 of the Year Winner - Modified
2021 C3 of the Year Finalist - Modified
2019 C3 of Year Finalist (appearance mods)
On my 75 L48 turbo 400 i went with the street option. B&M kit had street, rv, street-strip, and strip options to pick from.
Stock converter, get good firm shifts.
Stock converter, get good firm shifts.
