Summit Racing™ Performance Transmissions SUM-700380-SFI

Built for serious power, this remanufactured three-speed carries a 1,300 advertised horsepower rating and ships with a built-in trans-brake, a full manual valve body, and an SFI 4.1 safety-rated case liner, aimed at Chevy-bellhousing cars that need to leave the line hard and repeatably.

What sets this one apart

The internal solenoid trans-brake is billet aluminum, paired with a Pro-Mod 36-element drum and sprag and a direct drum modified for instant trans-brake release; clutch packs and end play are clearanced for low-drag operation with minimal binding. Thirty splines on 4340 steel in a TH350/400 pattern make up the input shaft, first gear sits at 2.48:1, and a billet steel clutch hub rides in an aftermarket aluminum case finished natural. The deep pan matches that natural aluminum finish, and the tailshaft runs 4.000 inches.

Bellhousing requirement

This unit is not lockup compatible and requires the SUM-700406 SFI 30.1-rated aftermarket bellhousing; it will not bolt up to a stock OEM housing. A converter, flexplate, controller, and wiring harness don't ship with it, nor does a cooler, fluid, or a dipstick. Sold individually.

Can I use my stock bellhousing? No, this case is built to pair only with the SFI 30.1 SUM-700406 housing. Is this lockup compatible? No, it's set up as a full manual, trans-brake-equipped unit instead.