I assume it's for a 302. I would suggest Holley PN: 0-90470, 470cfm, Holley Truck Avenger for off road angles. I don't know your engine build, so use the CID to cfm converter on this page. Don't forget .030" over is no longer a 302, it is a 306 CID.
Do your math if you want it right. Enter things like mild/moderate/big building specs, manual/vacuum choke, etc. Holley Performance Holley Products
P.S. An engine is an air pump. More air in must allow more air out. Exhaust needs to flow good also.