I recently built a 350 (bored 60 over) 1970 truck block
crane 302 adv dur (246 at .050) cam 500 lift
Pete jackson gear drive
10.1 pistons
400 heads bored to 2.02 valves and planed to raise compression
jegs roller tip rockers 1.5 ratio long slot
holley street dominator intake
1" carb spacer
Demon 750 speed demon double pumper mech secondaries 76pri 78sec jets
3000 stall converter on a th350 with shift kit
3:73 gears

it is in a 1980 chevy c10 pickup stock body with all glass etc

the problem i am having is i do not know if the carb is tuned right, or if the timing is right. I have a professional product harmonic balancer that has timing marks for up to 60 deg advance on it, and the truck seems to run good at around 45-50 deg advanced i have no vacuum advance, and it is a stock hei distributor with a msd electronic control module and an accel supercoil.
stock mechanical fuel pump puts out up to 9psi.

when i adjust the timing at 1000 rpm idle, it can only move between 40 and 60 deg advance at the timing marks. The crank came out of a 1985 corvette motor with the keyway at the 1:30 or whatever position instead of straight up like the newer cranks. I am not sure if i am reading the timing at the correct position, or if i need to hook the vacuum advance up or if i need to tune my carb again or what.

The problem is that the motor revs up to 4500 or so really quickly when i am driving and mash the gas, but revs up slowly to 6500 after that. i think the motor should rev up a lot faster than that.

I would like tuning tips as far as timing, fuel adjustments, gearing or whatever anyone can offer.  

I can't help with the timing issues but I can give you some info on your intake.I have a 1984 S-10 with a 388 stroker and I initially installed the Holley Street Dominator on it.I had the same problem with the rpms kinda slowing down around 4000 then it would pick back up at 5200-5400.I switched to the Weiand Stealth intake and now it pulls strongly and smoothly all the way to 7000rpms.  

do you think that it would help if i installed the carb without a spacer or with a taller spacer? I really like the intake. But i suppose i could change it.  

Did they deg. the cam when they put it in.Did you get the timing gear set to go with your crank, the cam could be degreeded wrong. You may have the wrong balancer and your timing marks are in the wrong place. You need to put # 1 cylinder to TDC and see where the timing marks are. 40 to 50 deg of intial timing is a little much. Shold be in the 15 to 18 deg range.  

I fixed the problem. It turns out that i had a single plane intake still at my house, so i ripped my holley off, and installed the single plane edelbrock torker. i stuck a 2" spacer on top of it to accomodate slightly for the 750 carb. When i went to put my distributor in, i was gonna change the cap and rotor, and i pulled the rotor off only to see that the counterweights for the timing had oval holes in them, and the pins they ride on were worn like 1/4 way through. I bought a billet accel distributor to fix that problem. I put in the lightest advance springs i had and set my total timing to 42degrees. The truck runs like a top and revvs up to 6500 with no problem now!!! So i think all along it was mostly the distributor, but the intake may have helped too. - I did put the cyl#1 to tdc and verified that my harmonic balancer was in the correct position as far as timing marks go. The cam has not been degreed- this was my first complete motor b uild on my own, and i am pretty happy how it turned out.