Cougar experts I need suggestions:
About 6 months ago I decided to try to improve my automatic transmission 1970 XR7 351 Cleveland 4 -barrel engine performance by removing the original carburetor and upgrading to a new Edelbrock 1405 600 carburetor. I also pulled the intake manifold (cleaned/painted) and replaced the gasket because it hadn’t been done like forever.
The car’s performance improved but after a few months to my dismay the engine developed a “whistling” at 1700-2000 rpms. As far as I can tell there is no performance issues but having my car whistle as I accelerate through that RPM range has become an annoyance to my driving pleasure.
I have since redone the intake manifold (thinking vacuum leak), done full compression check of engine (it is good), changed the carburetor to an Edelbrock AVS 1905 (plus gaskets to eliminate carb as source) to no avail. The car really likes the 650 CFM AVS carburetor however the whistle is still annoyingly there.
I should add this whistle is not there in park or neutral.
Any suggestions out there?
Thanks in advance,
Eric vB