Hi. I just got my 350 on the road in my 84.
I have 210cc patriot heads with 9.7 compression
with a 510 summit cam..
hurricane single plane maniforld ( what would be better?)
I have been driving it a few times now and it has crazy power up to 4500-5000 rpm then it bogs out and misses. I have a holley 750 vc seconday carb on it. The only mod done to the carb was a brown sping in the carb. I'm thinking its leaning out. Im running 8lbs of fuel pressure to the carb. I'm thinking of stepping the secondary jetting up to #80 jets and the jet xtensions. The car has very good power till it gets up to that 4500 to 5 it will roast the tires all the way. Im running msd street fire ignition with 36degres at around 3000 rpm.
Let me know what you guys think is going on.
Thanks
Travis

 

How is the fuel pressure when it starts to bog? Fuel demand at an idle is not the same as when under a load at 5000 rpm. If pressure is dropping to 2-3 pounds, performance will suffer. 8 PSI at an idle for a carb is too high. Max 7 PSI. You could also be draining the float bowls faster than they can fill. What size fuel line and how is the fuel filter?

Weak valve springs floating at 5000 rpm? Binding or broken valve springs?

 

will I have 1/2 fuel line all the way from the cell up to the fire wall then 2 3/8 lines runing to the carb. I have a summit 130gph pump and rugulator. I dont know if the fuel pressure is droping b/c my gaug is on the fire wall.. Im planning on moving it in the cab. The plugs are llike new yet and they pry have 4 hours of run time on them Im also running 87 octane gas. Im going to try to put a lighter secondary sping in today and im going to go out and run it. as for the valve spings there all new and say there good to .600 lift and 7500rpm Thanks for the help so far,

up to 4500rpm.......