Sorry!! New to this. Just need help with finding an adapter plate to mount a 600 Holley on a 12a.

 

https://www.racingbeat.com/RX7-1975-...nts/16464.html

 

Yes, the best and easiest way is to get a RacingBeat manifold. Many of RacingBeats's parts have been on backorder lately, but they have been so popular for so long, that they're usually available on epay or in the classifieds. I got mine in the classifieds a few years ago.

 

The stock manifold is more restrictive than the carburetor, kind of pointless to put a different carb on. Especially a carb as much of a pain to tune as Holleys are.

 

The 600 will be overkill for a stock 12A. You can make it work but the tuning will be very hard. And yes you will need to get the RB manifold to put it on there.

 

So if you already have a 600 Holley and you want to use it, then others have answered your question. You need the manifold from Racing Beat. It is still too much carb for a stock port 12A.

There are better options like a weber IDA or DCOE. Those carbs, out of the box offer more tuning options than the garden variety 600 Holley and can be sized to reduce/increase CFM potential. There are high end Holleys and Holley style carbs that have all of the tuning options of a Weber that also have interchangeable venturis like the Webers I mentioned. One of those in a smaller size or in a 2 barrel version might be a good choice. You would still need the Racing Beat manifold

 

the RB holley for stock 12a is more like 465cfm.

 

You'd also need a RB modified carburetor, unless you are patient and methodical, understand what all of the carburetor circuits do, and have a pin vise and a broad selection of small diameter drill bits.

Or a carb like a Quick Fuel where the idle feed restrictors and air bleeds and emulsion wells all have replaceable jets, instead of just drilled holes like a Holley. Then you just need the patience, understanding of what all of the carburetor circuits do, and a couple hundred dollars in jets.