Both headers are conventional collectors, no try Y or merge, just a 1 3/4 straight tube that we ran in the truck and the 1 3/4 1 7/8 step dyno headers. I have the truck headers here, I'll measure them. I know they are shorter than the dyno headers. I've measured them both before but don't know what I did with the lengths.gmrocket wrote: ↑Thu Nov 28, 2019 8:13 pmThat thing never gives up..randy331 wrote: ↑Thu Nov 28, 2019 12:05 pmThis is our 421 cube pulling truck engine.Scan_20191128.jpg
Top line is with the higher ratio rockers. 1.8/1.7 vs 1.7/1.6 it had.
Bottom line is the headers out of the pulling truck vs the dyno headers in the other 2 pulls.
The truck headers are fender well 1 3/4 tube x 3.5 collector, dyno headers are 1 3/4 x 1 7/8 step x 3 1/2 inch collector.
I'm happy with the flat power curve and it's hanging on to power past peak nicely, but I'm sure it can be better.
The bigger carb didn't gain anything. I was bettin that would.
So, we need to build our own headers that are closer to the dyno headers.
Does it just need more cam ?
I'm thinking maybe open the intake valve earlier ? Maybe open the ex earlier ?
A little faster lobe too ?
Just more cam ?
This is on a Stuska.
Are both headers conventional collectors, no merge/pinch?
Since it likes the bigger two step and your gonna build a set anyway, it wouldn't hurt to try a 2" section after the 1 7/8 with some different lengths and a merge/pinch
Did it every dive up top?
8500 rpm is as high as pulled on the dyno. That was the rpm range I wanted info on from this dyno session.