I've tried everything to fix the miss. there's no miss when it starts up, idles, or when you punch throttle. the miss is there at ordinary cruising speed which baffles me. i've changed carbs/msd box/distributor/wires/plugs/fuel pump/coil with no luck. offically stumped. a tech at msd & holley said to take a look at the timing chain & the cam to see if something wrong with the chain. welcome to this nightmare....
Could be chain. i see you've changed everything you can. Is the miss worse under load (going up a hill in 3rd on the highway) What are you running for timing? Initial, vacuum and mechanical advance? Are you using manifold or ported vacuum? Have you ever tried switching from ported to manifold or back. Have you done a recent compression check on all cylinders?
If it was chain I would think it would be rough all the time.
