I have a '68 Chevy C/10 stepside with a 292, Edel-1404, Offy intake and Clifford headers. The Offy intake is a close approximation of the stock cast-iron intake but in aluminum alloy. So it bolts right up. It has a deck which will accept a base plate for a 4Bbl squarebore carb. Carb heat is not provided, but may be added onto the bottom or between carb and manifold. The Offy intake will fit with the Clifford headers with minimal adjustment. Since I live in Tucson, I don't use carb heat.
My 292 is modified: Bored .030 over, Badger cast pistons, 1.84" (307) intake valves, Crane 260H cam, and Rhoads hydraulic lifters.
I now use an Edelbrock 500 CFM 1404. My carb set-up is Stock main jet (.086), #1452 (.070 x.052) metering rods, and Yellow [4" Hg] springs. The springs have the same function as power valves on Holley carbs.
I passed AZ emissions a couple of weeks ago on the 2nd try with minimal leaning of the carb.
The truck is my daily driver, isn't great on gas mileage, but is quick and nimble in traffic, and will move on the freeway. It roars at 2500 RPM.
