Listing calls it a Chevy 750cfm. It will bolt to the stock Pontiac Q-jet intake. But, you'll have to do some plumbing for the side inlet. And, will probably have to modify the throttle linkage to connect to the Chevy throttle lever. Would be a little easier to buy one with a straight front inlet.

New spreadbore Holleys ain't cheap. Probably not a good choice.

https://www.summitracing.com/parts/hly-0-6210

https://www.summitracing.com/parts/hly-0-80555c/overview/

Ebay lists quite a few used and rebuilt. A 650 is big enuff for what you want.

http://www.ebay.com/sch/i.html?_from=R40...amp;_sacat=6000