["Puddles the Pontiac"]

its been a while since i have posted here, i have been in the world of late model performance for a while. i have recently built a new motor for my '65 Lemans. specs are as follows ;

463 with eagle/scat/SRP rotator.
6x-4 heads w/heavy porting and 1.77ex valve (no numbers but professional work was done)
1.5 JBP roller rockers/pushrods
edelbrock T2 intake
holley 750hp carb

comp cams solid flat tappet custom grind.
lift .558i .580e
dur. @ .050- 260i 268e
110lsa

pertronix hei triggered by Mallory hyfire VI #685
module bypassed.

now that i have that out of the way, i built this motor to to give me high 11sec times and to be used w/ nitrous (i have a cheater kit). and at some point i will be adding turbos.after break in i gave this engine a quick "tune" by ear. i set the timing where the engine liked it and started good, set the idle mixture to the highest rpm. jetted by plug reading after a wfo pass down the road. now the engine barks when i rev it and sounds pretty good... in park. i take it out on the road and i have this frustrating miss. not a back fire or pop but a constant miss. here is an example in typed form if i may...
mmmmmmptmmmmmptmmptmmmmmptmmmmmptmmmm. at cruising speed. and i feel i am missing alot of power. i have changed and tested the coil, pickup coil, module, volts going in, alternator, plug wires. checked cam placement and valve lash as well. i feel this is electrical because i noticed the miss on the timing light while bringing the revs up in park. i installed the mallory unit hoping bypassing the module (hei distributor) and giving the coil a little more push would help things. i gained some power but still had the miss. now, here is another odd symptom, after resetting the distributor by putting the engine TDC on #1 and setting the timing to where it would start easy and idle strong, i checked the initial timing. i was at 50* of advance! i brought it back to 16* and that killed the engine. when i tried to start it it would pop a few through the carb and want to start. but wouldn't. 30* did okay but it wanted 50. if i went past 50 it went into a "blower surge" sounding idle. so i take off the cap, put the engine back TDC on #1, make sure #1 cap terminal matches the rotor, put the cap back on and fire it off. timing is at 30*. so i say to myself "fine, this $400 digital snap-on timing light is screwing with me". so i assume the light is off 30* and put the timing at 45*(assuming its really 15*). the engine likes it. so now i check the mech. advance. i go from 1000rpm to 1500 and the timing advances 10*. odd, i have the stiff springs on the advance weights but okay. i rev up to 2000 and the timing marks go crazy. they did this with the light springs too. oh and the miss is still there. so now i cant set my timing past 2000rpm. and as the engine gets warmer the miss is more pronounced.

so to put this in a nut shell,
my engine wants 50* of initial advance. it has an irregular but constant miss that shows up with the timing light. i cant set timing past 2000rpm. it is low on power. idle gets weak after warmup. and another symptom i noticed is, i can't get this thing to detonate on 93 octane. it was easy to do with the 290b-6 cam, but this one just wont do it.

notes of interest,
the only things distributor wise i didn't change was cap, rotor, and bushing. they all checked out good. as far as mechanically and visually. and the cam was installed straight up (same way i did with the 290b-6 which made alot more steam) crank dot at 12 o'clock and cam at 6 o'clock firing off cylinder #6.

guys, i am out of ideas and pretty down about the whole thing. i have been without this car for 2years. i feel i am a fair tuner but this has got me stumped. please help