I have an 88 K5 that is stock. The engine started running rough and wouldn't idle. Thought it was a timing issue. Set it, reset it and set it again, didn't help. It had some valve seal leaks (187,000 miles) so I put in a new rebuilt stock 350, however it was bored .30 over. I have checked all vacuum lines visually as well as with starting fluid spray while running. It will run with some throttle roughly, but no idle. Timing is right, does anyone have any suggestions? It's killing me to spend $1100.00 on a motor and still not have a truck that runs. If there is something I am missing or more information needed, let me know and I will describe as best I can. Thanks!