Edelbrock LD340 Intake Manifold Usable Max RPM?

I ran a non-cut LD 340 on my 10-1/2 to 1 340 years ago. Had an MP 557 solid cam, 3:91 gears and a Holley 3310 on a 1" spacer. Stock X heads and generic headers. This was in a 4-speed 73 Duster. It was still pulling strong at 72-7300 but I ran out of testicular fortitude.