I'm in the planning/pricing stages of a future engine build, and have a few questions for anyone who's overhauled one of the smog era 460s.

I'm curious about how exhaust gas is routed to the EGR valve.

Looking at photos of Edelbrock's EGR and non-EGR intake, it's clear that there's a port near the carb base plate for the EGR exhaust inlet. It also seems that there's a port on the back of the intake manifold on the EGR version that is not present on the non EGR.

At this point, I feel safe in assuming that that is one (and only?) exhaust port for EGR.

Are there any others? (70's small block Chevrolet engines have an EGR crossover in the cylinder head that leads to the intake)

Does any anyone know the thread spec for that port?

Thanks!

*edit* One thing I noticed when comparing the Performer series intakes to the Performer RPM is the passages between the center cylinders' intake ports. Does this work with EGR as well, or is it merely some kind of heat crossover?

(the basic reason for asking is that I'm trying to decide if I want to stick with the engine's original cylinder heads, or go a nice, new aftermarket casting)