1986 C20 stalls sometimes

[Zach86]

I have a 1986 crew cab short bed with the following modifications. It’s a 350 I put summit vortex heads on it with scorpion 1.5 roller rockers, retrofitted comp cams roller lifters, a crane roller cam .488 intake & .509 exhaust, edelbrock 2116 intake, edelbrock 1406 carb, a huggers GM5Xtm torque converter on a th400, with a 4:10 rear end. MSD coil, MSD box, MSD wires. My truck starts up and runs fine but if I punch it from a dead stop it won’t spin the tire, posi is my next add on. Once it’s rolling around 40mph it will run strong when I floor it. But it’s a dog below that. I was doing donuts in the snow the other day and it would just stall. Any suggestions?

 

[Bextreme04]

I have a 1986 crew cab short bed with the following modifications. It’s a 350 I put summit vortex heads on it with scorpion 1.5 roller rockers, retrofitted comp cams roller lifters, a crane roller cam .488 intake & .509 exhaust, edelbrock 2116 intake, edelbrock 1406 carb, a huggers GM5Xtm torque converter on a th400, with a 4:10 rear end. MSD coil, MSD box, MSD wires. My truck starts up and runs fine but if I punch it from a dead stop it won’t spin the tire, posi is my next add on. Once it’s rolling around 40mph it will run strong when I floor it. But it’s a dog below that. I was doing donuts in the snow the other day and it would just stall. Any suggestions?

Sounds like you need to tune the carb. Edelbrock carbs kind of suck to begin with, but can be ok if dialed in right. Did you make sure the floats were set right before you bolted it on? Have you set the idle mixture screws yet? WHat do you have your timing set at?

 

[Zach86]

I’ll start by saying this was the first engine I ever rebuilt. But it fires right up and idles. My timing might be a bit off because sometimes it will stiffer when I floor it but not every time. I didn’t mess with the floats but I’ve probably put 2500 miles on the truck since rebuilding everything. It just doesn’t give the performance I was expecting. It doesn’t feel much different then before picture of old cam va new.

 

[Matt69olds]

You probably need to play around with the distributor, the ignition curve is probably all wrong for your application. Definitely need to do some carb tuning, aftermarket carbs are calibrated fat and with lazy secondary tip in to run on any engine combination. You need to make the carb happy with your engine.

You said you have a MSD ignition box, are you triggering it with the factory HEI? What is the total timing number? How much initial timing? How fast is the advance curve?