Whats the deal here?

[66StangGuy]

iv had this issue for a long time with this motor.
new motor lots of cool stuff on it but it does not run like i think it should.

292 ci
world products windsor sr. heads. 202 160 valve
comp cams roller tip rocers.
edelbrock performer intake manifold
hooker super comp headers.
holley 600 vac.
Stock cam for now


everything is NEW and gasket matched and intake is ported to fit
the heads.

motor has great low end torq below 2500 rpm.
after that its a whole nother story.
no missing no hesatation or anything like that.
no obvious problems.

just no power!

it will rev nice till about 4000rpm then i have to floor it to get it to mabe get to 5000 in first gear with a c4 and 3.55 gears.

takes a long time to rev up.

same problem in gear or neutral.

Stock type distributor with pertronix and a msd coil.
35 plug gap.

any ideas what whould cause power loss at higher rpm?

only ideas so far is that i need a high rise intake manifold
and a carb spacer.