I have an 81 dodge W150, with a 76 dart ignition and an edelbrock 4 brl 500cfm carb. the truck accelerates just fine but when I back off to sustain my speed it studders but when I hit the gas it accelerates like normal. I am also trying to find out what the valve lash spec is with a 1982 head. Any help would be great.

What springs are you using on the vacuum pistons for your metering rods?
What you are feeling is the vacuum jumping up, and the metering rods being pushed back down into the primary jets. The engine goes very lean. You need to find a transition point that works. Try stifffer springs. Since our engines run at such high vacuum levels at cruise, get the stiffest springs you can to hold the high flow section of the metering rod in play as long as possible.
With the 500 cfm carb, you will see a reading close to 0"HG at WOT. I think the Carter/Edelbrock high rate spring is 10" HG.

CJ

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Part of Tyrde-Browne Racing

I'd also look over the driveline, engine/trans mounts and rear axle mounting.

'81 and newer slants were built with hydraulic lifters. Do you have adjusting screws in your rocker arms?

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Joshua

As far as valve lash goes is the engine older than 81? If it's 81 or newer it's a hydro motor and no valve lash required. Are you still deploying next month? Can you make the get together on the 3rd?

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83 B-150 slant 6,4 speed. 79 B-300 360 pathfinder 4x4. 74 W-300 318 4x4 git-r-done 80 B-100 sl6,4speed

Nothing schedualled for the 3rd yet but Im going to need directions.

where can I get the springs for this carb? I was thinking mabe on the edelbrock web site but I dont know.

Yes, I have adjusted my valve lash to specs.

You should be able to get them at a good auto-parts place. Probably even a bad one.

CJ

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Part of Tyrde-Browne Racing

http://viewmorepics.myspace.com/index.c ... D=43781572

is this the spring you are talking about?

Yep. That's the spring. Your photo link was broken, had to fix it. You have two of them in there. change out to the stiffest rate they offer. That should minimize the lean burp when letting off the throttle.

I don't have my list of spring rates. You should be able to look up what the rate is on the Edelbrock site. They are coded by color.

CJ

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Part of Tyrde-Browne Racing

sweet thanks alot I am heading to auto zone to see if they have any.