I went online to racing beat and they’re sold out on manifolds. I’ve heard of people buying adapters and drilling holes on the stock Nikki position. After that installing the Holley . Also what would I do with the omp lines I hate seein those Holley with omp lines coming into the venturis holes . Might as well block the omp and premix which I have already been doing . Thanks for any input don’t need no dumb answers please is a 12a streetport and this would be until racing beat have the intakes back in stock.
it’s also a Holley 450 already tuned for a streetport 12a.

 

On the 4160 family of carbs (like your 450cfm) there is a "sight glass" on each of the float bowls. On the RB Carbs they unscrew the primary bowl's sight glass and thread a nipple in there, and hook the OMP lines to that. You'll need to "Y" them together to hook up to the single nipple.

I can't help you with the 12A Holley intake though... I have an order in at RB for a 13B intake and they said 10-12 weeks.

 

i hav a used RB 12a intake.... let me kno your interested .... it was slightly ported for a 600cFm it will work with carb .... PM me