Just rebuilt my 460 for 82 van used for towing. Has original Holley 4180, after market edlebroch manifold. Straight up timing chain. I have the initial timing at 10 btdc. I read in the posts that timing at 3000 rpm should be about 38. Mine won't go past 28. I cannot tell there is any vacuum at the timed port on the Holley. I put a vacuum gauge on it, ran engine 30-60 seconds @ 2500 rpm and vacuum gauge does not budge. Carb was redone not very long ago, so looks clean. Any thoughts on how to get vacuum at timed port on Holley? Thanks

 

I have an '85 F250 with the same engine, carb, ect. My vacuum advance hose is connected directly to manifold vacuum source. You mentioned some work was done on, possible hose connected to wrong source of vacuum, hope it helps.

 

First of all set your initial timing to 10 deg. with the vacuum hose unhooked.

Then hook up the hose to a Ported vacuum source. On your carb there is either manifold (vacuum all the time) or ported (vacuum at part throttle). You can use a vacuum guage and try to find a ported signal from the carb. You will have to open the throttle with the vehicle in gear to get the throttle open enough to get a good signal. Just make sure you have one foot on the brake.

Nick from the frozen north
1974 F-250 4X4
soon to be 429
dana 60 front and rear