The 1947 - Present Chevrolet & GMC Truck Message Board Network

1: you will have to add an electric kickdown switch to the throttle instead of the current cable your turbo 350 uses. 71-72 The switch is located inside the truck above the throttle pedal, 68 to 70 uses an electric switch at the carburetor.

2: The driveshaft yoke is larger diameter at the slip joint and has a larger spline pattern.

3: some turbo 400s will use I slightly larger diameter three bolt pattern that attaches to the flywheel. most fly wheels are drilled for both patterns. If yours is a mismatch you can either use your original turbo 350 torque converter in the 400 or drill the flywheel holes using the converter as a pattern.

4: column shift linkage is a straight bolt on, No changes required.

5: cooler lines are ball park in the same location but require some slight bending to align correctly. Sometimes different size cooler lines. You can swap the cooler line adapters from the turbo 350 if they are different to match your original cooler lines.

6: if your turbo 350 is a short shaft and the turbo 400 is a short shaft, turbo 400 is just a little bit longer and you almost always have to shorten the driveshaft slightly to match.

7: make sure your turbo 400 has a dipstick and dipstick tube, this is different from the turbo 350 as well.

8: vacuum modulator hard tube from the intake manifold is a little bit too long for the 400, can usually cut off the extra and run a soft line to the modulator on the 400.

Steve weim55 Colorado