I would ask whatever vendor you use if it was Made In America.
A few phone calls will get you to the bottom of this and make your choice easy.
I've heard a few stories of Corvette owners who bought cheaper products and found they were'nt worth a darn. Turns out they were made in China or somewhere else that could care less.
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Before condemning the EGR valve because it doesn't hold vacuum, you must first determine if it is a ported EGR, or a Positive back pressure(PBP) EGR. A PBP valve will NOT hold vacuum unless the engine is running at a rpm higher than idle. It needs a little backpressure from the exhaust to seat a valve inside, before the vacuum can control the operation of the orifice. I would suggest testing it that way before deciding it is bad. Not all '75 engines had them, but they were available, so.... Most of the time, a PBP EGR valve will identified with a "POS" stamp on them....you might look and see if yours has that. Regardless of which type of valve you have, you will need to replace it with the same type, if you do replace it. I can e-mail you a PDF on identifying and testing the different valves, if you want.
____________________________________ Joel Adams C3VR Lifetime Member #56 My Link
Corvette is a registered trademark of the General Motors Corporation(GM) &
Chevrolet Motor Division. Vette Registries, LLC is responsible for all site content (except for member submitted content or where otherwise
noted) and does not claim or imply that Chevrolet or
GM is responsible for Official C3 Vette Registry content. Vette Registries, LLC is independent from GM and is not affiliated
with, sponsored or supported by GM. Copyright/trademark/sales mark
infringements are not intended, or implied and are in fact used to support
GM, Chevrolet and Corvette.
Official C3 Vette Registry content is Copyright 2001-2017, Vette Registries, LLC. Content may not be reused without written consent. All Rights Reserved. NS
Corvette (Vette) Model Years on this site: 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982