My friend has a '91 c1500 with the 350. The timing keeps coming untimed? will slip a few degrees either way. happens usually in a few weeks. just changed timing chain/sprockets aand did not fix it. Will lose ALOT of power when this happens, but change it back and its stong as hell. Anyone got any ideas?
Thanks

 

by losing timing i am assuming that your distributor is moving. i would pull the distributor out and clean the surfaces and replace the distributor gasket. i would also replace the hold down clamp and make sure the bolt and threads are ok.

 

i will try tht