Strange problem

[goinbroke2]

Originally Posted by X-TECH MAN

Not to argue with Jody but I disagree with his solution. Im no expert but I always thought that if it was valve springs the problem would show up more in 2nd and high gear. The RPM come so fast that the engine swings thru the valve float before it becomes a problem at the shift point but the slower RPM swing in the upper gears causes it to show up more in the upper gear ranges. This is just backwards from what Jody said. This showed up in the old Jr. stock days for me with OEM valve spring pressures and the early days after NHRA changed the cam and valve spring rules before the "Shubeck" type lifters came onto the scene allowing the crazy valve spring pressures of today. Anyone who builds engines have a comment? Adger are you out there? Again not to argue about it but just what I have experienced.

I too experienced valve float in 2/3 but in 1st (or pissed off in neutral) would spin to 6700.
Wrong springs came with cam. Spring pressure was correct for those springs, but the cam called for a bigger spring. The clue (after chasing EVERYTHING but springs because they were "new" and "showing correct") was when I added a .030 shim and picked up 700-900rpm before nosing over. Threw on an OLD set of much bigger springs and the bitch went to 7000 no problem!

So, what is it? Need more info really. One thing I would ask is what size of fuel line and how much pressure does the pump push...actually..the pump is pushing fuel not pulling from the front right?
Here's my thinking; If you have replaced the factory line with a bigger 1/2" fuel line and and you have a smaller/weaker pump, even if you have the "proper psi at idle" when you leave the line the weight of the fuel in the line is going against the fuel trying to be pumped forward basically stopping flow. Once your into 2nd the G's drop off and the pump can overcome the weight of the fuel.
But, not knowing carb/pump/line size/if you wheelstand/etc it's a shot in the dark.
So, one check is watch your fuel pressure when you leave the line and see if it snaps down then slowly creeps up.