[Zeke's Garage]

If your 307 was like the one I pulled out of my Chevelle wagon, it probably had the nylon teeth coating on the cam gear of the timing set, and they might all now be in your oil pan, causing some crazy timing issues.

Otherwise hook up a vacuum gauge and check for any jumps and variations in the vacuum. The only way the vacuum will drop in the manifold, is if something allows outside air in, like opening the throttle, or a significant leak somewhere. So block off ALL vacuum sources while you're troubleshooting.. power brakes, trans mod valve, vacuum advance on the distributor. If you're still seeing drops and jumps, it's time to check your valve train and verify your static timing.

Good luck with it!

Shawn