Looking for some feed back here as I know there are lots of good minds on this site. 
I have rebuilt a 292 with a 312 crank, mains ground down, stock 312 rods. Engine has G heads Mummert intake, valve train, and Ramhorn exhaust, also running a new pertonix flamethrower distributor and an Edelbrock 500 cfm carb.
Issue is I'm at 30* initial timing and pulling only about 13" of vacuum. I'm at 600' elevation. I can't get more advance unless I restab the distributor due to vacuum advance  hitting the manifold, and I think it would run better if I did, but dam...
I'm having no starter drag where its at, it  runs good, starts good, temp is good, but I'm coupled up to a T-5 transmission and don't have much pull at all in 5th gear, rpm is under 2k at 70 mph with a 3:73 rear gear. Overdrive gear is 0.63 so I don't feel it should be too tall. Only have about 20 miles on her now, btw its in a 56 F-100
Cam is a Howards 292002-10 advertised lift of 0.463 and 255* duration gross lift at cam of 0.315 and 219.8* duration @ 0.50. 110 lobe separation, 106* intake center line.  Valve lash is now at 0.020, card request .022.
I'm almost thinking dampener dude may have put my dampener together a bit off. But during assembly TDC was correct with my timing mark. Thinking of stabbing the dist back in with timing mark at 10* and rotating a tooth back to get some manifold clearance for the vacuum advance canister, and see what it does with even a bit more initial timing. No sign of pinging where its at now but it just seems extreme to me. I know these engines love some advance. But what the heck?
Timing set is also true roller from John installed straight up, per instructions.
Yes vacuum advance was plugged off when timing and it's to ported vacuum on carb. 
Anyway thanks in advance for any thoughts and feed back.

Yeah, Ted I measured it against the original 56 distributor, and just did again and they are both 5" from the base. Gear width is the same, diameter is the same. 
Here is a photo of the gear mesh.