Here are some specs, a picture, and a link to Jegs website with more info.
(Says idle to 4800 rpm in one paragraph, and then it says idle to 5500 rpm in the next?
Part # 510-300-38
Idle-4800 rpm, Dual Plane, Square & Spreadbore Flange
Works equally well on the street or at the track thanks to its dual plane design that enhances fuel distribution and its raised plenum divider that improves torque. Accepts both spread bore type and Holley flange carbs. Features late model alternator and A/C bracket mounting provisions. No EGR.
Features:
* Idle-5500 RPM power band.
* Low rise/dual plane design.
* No EGR provision.
* Spread bore and square bore carburetor mounting flanges.