Thread: TH350 to 305 CSB

Tweet

No tranny swap experience - will the TH350 mate up, without adapters, to the Chevy 305 (this one is an '88)? I am pulling a TH200 out - will the 200's flywheel/torque converter move over to the 350? Lastly, will any vacuum port on the carb work for the vacuum modulator? Thanks, Hal

No adaptor plates required. Just make sure the flexplate is correct. One piece rear main and two piece rear main seal engines are different from each other which also requires starter nose offset to match. In other words make sure the vintage of the motors are close to the same. Pre 84 will all be an easy exchange. Example; 83 engine being pulled out and a 96 engine being put in will require the flexplate and starter change to accept the set up. I know I'm creating a bit of confusion, just keep the years within the same generation. Manifold vacuum for the modulator and do not share the pcv port for this use. Properly mate a correct torque converter to the 350. If it's a used unit, drain overnight and put in new fluid.

I guess today isn't my brightest day. The 1988 305 CSB will mate up to the TH350 if the tranny is of the same generation - correct? Any idea what range of years I have to work with as for as picking up the 350 tranny? Thanks, Hal

for ease of installment, keep it pre 84 .....As of late 84 into 85 they started getting ready for the 86 one piece rear main seal attitude. Arguments abound about the time table, but it doesn't matter. Stay pre 84 for good measure. Tranny is not the main issue, work with the motor selection first and keep the right torque convertor in the 350THM for your satisfying install.

Nitrowarrior, thanks for the help and clarification. Hal