holley metering block ?s

ssba said
Yes. Allen plug screw in brass inserts. #6, 8s & possibly 10-32 next to the power valve.I believe. I noticed they were different than Holley's
ultra HP blocks like you say.
I also seen where holley sells raw or unmachined HP blocks.
I am starting to consider this is their origin.

ssba said
Fishy68 I haven't been able to locate my # drills. I must have loaned them out
and they disappeared some time ago. I will have to order a set to get back with you
on the sizes used.
That may be the best we can do on these. I may have to get some new inserts and
drill them for a particular use? Although I wouldn't know how to choose sizes myself.

Gotcha. I looked all through my book and don't see those #'s, sorry. My book is an older publication and after looking through it good it apparently only has the very early HP blocks in it. I didn't know Holley sold them un-machined but that is a possibility.

Generally you start out with emulsion hole sizes of .026-.027 and tune from there. The PVCR size is determined by the size of the carb and jetting. The idle restrictor sizes vary from .026 on smaller carbs to .033 on larger carbs with engines that need more idle fuel. If you decide to part with them let me know. I might be interested in them