I've been playing with my big heavy Dakota (4200#) for awhile now, but just recently switch it over to MS3X for engine controls. While the truck is running good, it isn't pulling in high-gear like I think it should. I took it to the chassis dyno to nail down the timing and AFR. I got that accomplished, but now I am able to see on the dyno chart that it is in fact falling off in the upper rpm range. It will rev to 7,300 pretty easily, but it's not making more power up there. It used to when it was supercharged, but of course the "area under the curve" is much greater now, so it goes quicker.

This is a mild .030" over 360, a set of home-ported EQ 2.02 heads and an M2 2bbl, with 50mm F&B intake. The cam specs are 236° @ .050", .512"/.512", 114° lsa, and is installed 4° advanced. I'm also wondering if I should install it straight-up or even retard it some. Like I said, it used to make more HP at the top of the rpm range when supercharged. I'd like to get it back. With the same cam, the HP used to climb the entire way until shift point of about 6500.

I'm trying to reason out whether it's a valve spring issue, or a too small of a turbine issue for this much exhaust flow. Turbo is a T-76, .96 A/R on a T4 frame. Exhaust is a single 4" down pipe that dumps right before the rear tires. I also need to make more suspension/chassis changes to get it to leave better. It's hard on tires, but still manages 1.5 60' numbers with good track prep.

i would retard the cam -4 from 0 & try it before i spent money on other things.

Yes. It would be the cheapest thing to try. Just gaskets and some labor.

Without seeing the boost and exhaust pressure graphs, i wouldn't do anything.

I'll have to find a way to measure my exhaust pressures.
Once I measure them ...

What kind of differential pressures would be ideal?
What kind of differential pressures indicate a problem?

if the exh pressure is more than the boost pressure ,the exh pushes into the combustion chamber & intake trac,this happens during the overlap cycle,a blower does not have this issue ,----cam timing or turbo to small.