chevysteve2

ready to pull my hair out.

I have a crate zz 502. everything is new on this motor. I changed the stock (224/236 @ .50)cam to a 236/242 @.50, put in roller rockers. The problem I have is when it hits 5000rpm it misfires. I have a mighty demon 825 cfm. I have a 6al box. I have changed the carb with a 850 DP and it still misfires. I sent the msd box back to the factory and they tested it and said it is good. MSD said that the box will work the same at all rpm, along with the magnetic pick up in the HEI distruberter. I changed out the coil with a another blaster 2. A friend said he thought I had weak valve springs. the stock springs have 135 at the seat. the comp cam springs that the camshaft calls for, have less seat pressure. the new cam has .20 less lift. I spent 700 bucks on a chassis dyno and tuner today and parts. My tuner could not figure it out. A visual check was peformed on the springs. The car runs excellent, good idle, but when it hits 5000 it falls on its face. Hp peaks at 3500 and slowly tapers off until 5000 it steeply falls off. The jettting was almost dead on, he fattened up the primaries to get it perfect. The A/F ratio stayed at 12 the whole time. He put in new plugs and wires and a new msd billet distruter. timing was at 34 total. nothing changed. The next thing I will do is put new springs in. Is ths a waste of money? Does any one have a suggestion?


thanx,
steve :arrow: :evil: :evil: :evil: :evil: :evil: