Have you considered a Holley 670 Street Avenger. Ran that on two 383 cars with great experience.

https://www.summitracing.com/parts/hly-0-80670?utm_source=bing&utm_medium=cpc&utm_term=%2bholley+%2b0-80670&utm_content=Holley&utm_campaign=Part+Number+Ad+Groups

Summit link to Holley SA 670 cfm