B&M 30262 Shift Improver Kit GM Turbo 350 TH350

The B&M 30262 Shift Improver Kit reprograms the hydraulic circuits inside a GM Turbo Hydra-Matic 350 (TH350 and the lockup TH350C) so the transmission shifts firmly and holds each gear instead of dragging through a soft, overlapping change. A stock Turbo 350 lets shift pressure bleed off to keep the change soft; over miles and under load that slip is what glazes the clutches and burns the bands. This kit raises and quickens the apply so the clutch packs lock without slipping.

You get two calibrations in one box. Stage 1 gives a firm but still smooth shift for towing, RV, and heavy-duty street driving. Stage 2 is the more aggressive street/strip calibration for full, hard shifts. You choose which one to build during the install.

Installation is done on the bench or under the car with the pan dropped. You remove the valve body, swap in the supplied separator plate and springs, drill the specified passages per the printed instructions, and reassemble. No special tools beyond normal hand tools, and the kit works with a stock or rebuilt Turbo 350. It is a common first upgrade during a TH350 rebuild or a fix for a unit that has started slipping on the 1-2 and 2-3 shifts.