402 BBC in 92 K3500

[DeuceLoosely13]

I recently swapped in a 402 BBC in place of the tired old 350. Everything is working fine except the clutch. It isn't disengaging the clutch correctly. It is an NV4500 transmission. I used the flywheel from an older truck and the clutch, pressure plate and throw out bearing from the 92. Can someone point me to the correct combination of parts?

 

[b454rat]

Did you use the flywheel off the 350? Tho they are considered neutral balanced, they still have an external weight near the ring gear I believe. The 402 is internally balanced, and that flywheel is the wrong one for your motor. Surprised it even bolted up....

 

[Schurkey]

Did you use the flywheel off the 350? ...that flywheel is the wrong one for your motor. Surprised it even bolted up....

Not possible. The not-neutral-balanced flywheel from a one-piece rear main seal SBC won't bolt onto a BBC. Bolt circle is smaller on the SBC.

Guessing that there's an issue with the throwout bearing length, the pivot-stud length, or the linkage adjustment. But it's been so long since I've been into a clutch that I hardly recognize the parts any more.

OTOH, if this is a hydraulic clutch, I've had problems getting the system bled properly. I ended up pounding the clutch pedal from foot-off to "on the carpet" about two hundred times, as fast as I could pump. That is, pump 20 or 30 or 50 times, hold the pedal down at the end. Let the bubbles rise to the top. Release the clutch so the bubbles get pushed into the reservoir. Repeat. Make sure the reservoir doesn't run low.

No amount of bleeding at the bleeder screw was helping.

 

[b454rat]

I thought it wouldn’t physically bolt on but it’s been awhile for me too lol. What type of clutch is it? Borg n Beck or diaphragm? I did a SB to BBC and used the heavy duty clutch and the pressure plate would rub the fork. The flywheel was thicker on the BB, pushed it into the bell deeper….