Just wondering, did you find/fix the problem?

Was the cam degreed?
Does the throttle actually open the carb fully?
You really sure you got all the plugwires on in the correct order?

Hey guys here is an update. I finally got some time to go and work on the car. I put the .040 shims in first. I fired it up, and it still acts the same. Should I still try an additional .020 of shim?

I'd go back over the basics starting with a compression test. More detail on how it's acting at 4K. (in the driveway or under load & WHAT is it doing) Did it always act this way since built or happen after a part/tuning change or out of the clear blue

Wonder if it's running out of fuel mechanical pump?

Valve spring shims are not meant to be used to increase valve spring pressures. They are meant to be used to correct installed height. Using them to increase pressures can cause problems like coil bind.

I don't see how it could be fuel delivery problem unless the carb is all junked up, there should be MORE than enough fuel in the bowls to allow the motor to rev up to 3,000 rpm in neutral. I think one time I turned my fuel pump off and the engine kept running at idle for another 5 minutes.

You might not want to hear this, but check the cam timing or valve springs.

or before you check those, tell us what changed right before this problem occured. did you do a cam swap? or did you replace the timing chain/gears? did you change the heads?

instead of just blindly adding shims, pull off your intake and actually look at the lifters to get an idea of how much preload you have in them.


If this is a brand new engine that you're still trying to tune it in, then check the valve springs and check your cam timing. with a degree wheel and a dial indicator, you can check the cam timing and not even remove the timing cover. (but you will have to remove a valve cover to put a dial indicator on #1 intake valve)

thanks for the help so far guys. This is a new engine that was built at a machine shop, I bought it second hand from a guy in my car club and the machine shop is not around any longer. I do know the block was decked (how much, not sure) but enough to wipe off the stamping on the distributor pad. That is why I tried the shims, to increase the height for the pushrods. I think I'm going to have to get someone from my club with some free time to come out and help me, as I don't have the expertise or tools to investigate further at this time. Thanks for all the help so far!

Sounds like you were using rocker shaft shims which are meant to correct geometry. and you weren't using valve spring shims or if you were valve spring shims will do nothing to push rod length.
I would like to see ow that cam is degreed in. Been down that road with no RPM's and the cam degreeing is off.