Help with Timing, Vacuum and Backfire - 289c.i.

[Phillyfanfrombirth]

I'm trying to figure out how you fit a 1.94/1.6 valve set up into a stock 1966 head with any kind of lift... that must be one heck of a squeeze. I have those valves in a set of Windsor Jr. heads, but those chambers make the stock heads look tiny.

That said, any possibility of some valves sticking open? or the rocker arms torqued too tight?

"ARP bolts and studs"... I would take this to mean that you've pulled the stock rocker studs and you've replaced them with screw in studs? If not, check your studs with a straight edge to make sure none have dislodged... If any look out of whack (I had one sticking up about 1/4" one time) they will have to be pulled and replaced.