topbanner ad

Tuesday 18 October 2022

Baker Drivetrain

The Baker 6-into-4
It is ten years since Bert Baker's 6-into-4 was featured by the Discovery Channel in its 'How Its Made' strand, and it remains a unique and uniquely specialist piece of kit - a true overdrive 6-speed to replace stock 4-speeds, "designed to satisfy old school tendencies while providing the ability to run at reasonable rpms at modern highway speeds."
"The 6-into-4 gearset design is based on our original, award-winning overdrive 6-speed and is tough as nails. With our 6-into-4, you'll get all the benefits of an overdrive top gear, smooth shifting and the ability to stay in the powerband."
An upgrade to any 1936-1986 Big Twin 4-speed, it has many gear ratio and case, shift system and cover options to choose from, and all 6-into-4 case options come with a machined-in 5th stud. 


"We took the weakest point on other aftermarket transmissions and made it into the strongest point on ours. The 5th stud commonly breaks out of its bolted-on plate causing your driveline to tweak in the chassis.
"The 6-into-4 transmission case comes in two different versions - our 1936-64 case is a no-ear case to work with the factory primary; our 1965-1986 version comes with the primary ear bosses on it. These can be used with stock primary applications, belt drive applications, or running no primary plate at all.
"Both cases have a provision for an electronic speedometer which would utilize a stock 1996-2006 speed sensor. Subject to what type of electronic speedometer you use, an additional speedometer recalibration box is separately available; the Baker 6-into-4 case does not have a gear drive speedometer cable provision on the case."
Baker offers it in three mainshaft lengths - late 1984-1986 for diaphragm type wet clutches, 1970-early 1984 for Shovelheads and 1965-1969 for Panhead/Shovelhead.
All Baker 6-into-4s come standard with its Klassic kicker gears. Made out of 1018 HR steel, tumble finished to around a 20 micro and heat-treated to 50-55 RC, "these gears roll smooth as glass. We manufacture and offer three different kicker covers, making the 6-into-4 completely customizable from stock to custom build.
"It comes with a straight kick arm and as standard with a single-pole neutral switch top cover and Baker hidden vent design. The transmission can be ordered with our no-neutral top cover.
"Each transmission is hand-built to order with a 23-tooth chain sprocket as standard. Optional 24- tooth chain sprocket and 33-tooth belt pulley are available to order. The 6-into-4 has two more gears than a 4-speed and sticks out 1.6" more. The rear exhaust pipe, oil tank brackets and starter brackets may have to be modified for fitment. The electric speed sensor provision in case accepts stock 1994-up speed sensors; some 1970s inner primaries may require modification for sprocket nut clearance."