I HAVE AN 86 CHEVY C10, IT WEIGHS 4080LBS WITH ME IN IT. IT HAS A 355, 9.5 COMPRESSION WITH COMP CAM 12-210 .454 LIFT AND 218' @ .050 110 LSA. AFTERMARKET 180 INTAKE CC  HEADS, PERFORMER RPM AIRGAP INTAKE AND AN EDELBROCK 600 CFM CARB, STOCK HEI WITH FULL ADVANCE COMING IN AT 2200 RPM AND AN ACCEL COIL. IT IS BACKED BY A BUILT 2004R AND 3.73 GEARS. NOW IT RUN GREAT AND COULD REV UP YO 6000 RPM EASILY WITH NO LOAD. BUT WHEN I WENT TO THE DRAGS IT WOULD SEEM TO BOG OR STOP PULLING AT 4500 RPM. ITS NOT RUNNIN LEAN, THE PLUGS ARE TAN. IT MOMENTARELY BOGS AT 4500 RPM THEN CATCHES AND STARTS SLOWLY PULLING UP TO 5000 RPM. I WAS THINKING IT MIGHT BE THE IGNITION MUDULE? WHAT DO YOU THINK. IT IS IN GOOD MECHANICAL CONDITION AND NEW ACCEL WIRES AND ACDELCO PLUGS.  

I have basically same setup in my 87 c10 only 383 w/roller setup(218@.050)w/180dart iron eagle.Ihad all sorts of problems with the eldelbrock carb. i've since switch to a 750 speed demon made a world of difference not saying thats your problem.first thing i would check would be fuel pressure also check that you don't have any bent lines. next check your timing i'm using a performance distributor w/ live wires they have mine curved at28degree@2600rpm.by the way i'm knocking down 16-18mpg around town 21-25hwy if i keep my foot outof it.kinda hard to do.  

I don't think it's a fuel issue. I think you've got a valvespring problem. What valvesprings are you running? My guess is, your valvesprings are surging at around 4500 RPM, and when the springs do this it'll make the motor bog until it gets outo f that RPM that the springs have a bad harmonic problem.  

i think its the fuel pump. i am using a stock mechanical fuel pump, i'll just buy a holley 110 gph, its cheaper and it might work. what you guys think?  

any suggestions GibTG???  

How did you come to this conclusion? Did you check the fuel pressure at the rpm where you're having your trouble?
I once had a 110 GPH holley pump for my 355, and while under high load for a long period of time the pressure would drop right off to around 3 psi. Too low of course.
But more than likely the pump would be enough for your combination.

Sounds like a valve float problem to me if the fuel system checks out. I had a near exact problem happen with my 355. I bought the springs in conjunction with the comp cam, and so it turns out, they were not sufficient for much past 5K. I think that a big issue is that these smaller cams and spring combos were originally intended to be used with stock 1.94 valves. But that's just an assumption.

What do you have for valves? Are they 2.02 1.6?  And what do you have for rockers?
The reason that I ask is that if it is truely a fuel delivery problem, it wouldn't "catch up" as you described in your thread; it only gets worse the more R's you give it.


JC  

im  using the stock rocke arms and the springs that the heads came with the machine shop. and yes the valves are 2.02 and 1.6  

I would suggest finding the specifications on those springs and give Red at Comp Cams a call. I would speculate that they are not sufficient for the camshaft that you're using. A spring change can really change the way that an engine performs, especially at those higher revs.

JC  

THANKS FOR TAKIN THE TIME TO RESPOMD TO MY QUESTION JJCCORVETTE. WELL I CHECKED THE FUEL PRESSURE AND IT DROPPED NEARLY TO 2PSI AT 4500 RPM AND THE TRUCK STOPPED PULLING AS HARD ALMOST LIKE IT HAD A REV LIMITER BUT IT KEPT PULLING SLOWLLLY. NOT SURPRISING, IT IS ONLY A STOCK FUEL PUMP  

THANKS FOR TAKIN THE TIME TO RESPOND TO MY QUESTION JJCCORVETTE. WELL I CHECKED THE FUEL PRESSURE AND IT DROPPED NEARLY TO 2PSI AT 4500 RPM AND THE TRUCK STOPPED PULLING AS HARD ALMOST LIKE IT HAD A REV LIMITER BUT IT KEPT PULLING SLOWLLLY. NOT SURPRISING, IT IS ONLY A STOCK FUEL PUMP