Holley 1920 problem

All intakes interchange. Later EGR ones need a block-off plate ($15 ebay), or just leave the EGR valve on & closed (no vacuum). Of course, desireable intakes cost much more. A factory 2 bbl cast aluminum is primo, and similar price as a 4 bbl aftermarket unless you find a junkyard one or clueless seller. Some guys here lucked onto some 4 bbl ones on J.C. Whitney's site at a good price, but they were snapped up in an hour. Avoid E-beam welded alum intakes (late 70's-80's). They are extremely light, but many say they can be porous along the ugly weld line (looks like lava). You see the 2 split pieces when viewing the cylinder ports.

Factory Exhaust manifolds vary in the thermostat heat well, but otherwise interchange. After-market headers don't fit the shorter 170 engines.