Success!... Not so fast

[1BAD68]

Well, after doing a magnum head swap on my 318 over the winter and trying 3 different sets of pushrod lengths, I finally got it right.
Initially I measured with an adjustable pushrod checker then ordered pushrods but had a lot of noise like a sewing machine.
Realized that I forgot to add preload, I ordered another set. It was better but still noisy.
Then I ordered a 7.700 set and the noise is gone and it feels like I picked up another 30-40hp.

[b5blue]

I'll bet ya did pick up a bunch of torque also!   

[Kern Dog]

Boo-Yah !

[1BAD68]

Ok this is strange but I need some advice.
When I start my car and drive normal, everything is fine. No valve train noise and lotsa power until the first time I mash it to the floor. It'll do a nice smoke show and all that but then the valve train noise starts again and it runs rough and loses power.
But if I pull over and shut it off and let it sit, I can hear a sound like the lifters bleeding down. It makes a clicking and creaking noise that sounds like a hot engine cooling down.
Once that noise stops and I start it up again, it's quiet and has lots of power again.
What causes this? Weak lifters?

[1BAD68]

it remains a mystery

[heyoldguy]

Did you buy pushrods that oil goes through to the rockers?

[b5blue]

Lifters "pumping up" possibly? 

[1BAD68]

I think I may have a bent push rod or two but won't know for sure until I pull em. The noise seems to be there all the time now but sounds more like it's isolated to just a couple spots.
So I went from 7.600" Trick Flow's to 7.634" Edelbrocks to 7.700" Howards.
The only choice I can find now is 7.650" in the 5/16"