Problematic 351c wont idle.
This motor was my daily driver, never missed a beat. Parked it up for 12 months and started it to find it now runs like a chev (poorly). I changed carb and manifold (had 2bl on it, now 650 sq bore) thinking the carb had dried up internally and it was a good excuse to change to 4 barrels. Nothing, striped disty to find the throw weights and other parts were seized. so i bought a new HEI disty/50kv coil thinking it would sort it, nope..... still runs poorly.
When it starts it wont idle, it revs under load very nicely, but reving with out throttle load produces a very ragged broken sound (like a misfire but never on the same cylinder) i have tried running it leaving one lead off to isolate a dodgy lead and it makes no difference other than a constant miss as well as the random miss. Oh... we have rotated timing both heavily adv and ret to see it there was any alteration in idle but nothing changes (minor pick up or down in revs but still never solid)
Could the diafram in the brake booster have cracked? could this just be a simple low vacuum issue? I have no guages to get a vacuum reading and have left it now for a month being a little de-moralised after digging deep for the carb/mani/disty.
Any suggestions on what to check and in what order?
Thanks in advance,