heat shield for my slant six!! HELP
1. EGR systems came into common use in the US in 1972.
Well, '72 in California, yeah. '73 in 49 states + Canada.
All of them have vents under the carburetor which allow exhaust gasses to pass into the intake for re-consumption. Almost by definition, an EGR valve is in the intake on a carbureted engine.
Some Fords and Volvos had a different arrangement, but we don't talk much about off-brand cars here. All Mopars with EGR, yes, have the valve on the intake manifold and require the exhaust/intake "overlap" (as they weirdly call it).
I have not seen an inline, ohv, pushrod motor that didn't have at least two ports siamesed.
The way I read their misuse of the word "overlap", they mean the intake manifold hot spot, heated by the exhaust, where the intake and exhaust manifolds bolt together.
This seems to be the only leg they have to stand on. Most carbureted cars built in the US since WWII have had cast iron intake manifolds.
Sure, but if that's a leg, it's a gimpy one. "Some castiron intakes have had a heat issue also" makes less than zero sense.
The throttle bore on the 1920 is 1 11/16
Or 1-9/16", depending on which specific 1920 (or Carter BBS, or Holley 1945) we're talking about.
where the hole in the plate is 3/4. This means that the hole in the plate is 1/16 too large.
Not an issue; the hole in the carb flange gasket is also larger than 1-11/16" and makes no problems.