Is there a formula or work sheet that I can use to get a rough idea where to start with the primaries and secondary jet sizes on my 4150 carb? I just don't feel like going thru the whole scale but would like a starting point. Thanks

The orginal set up ia a place to start, look up your list number here.

http://documents.holley.com/techlibrary_carb_numerical_listing.pdf

What size engine? what CFM is the carburetor?

The engine is a 505 stroker and the carb is a ProSystem 1000 cfm. The jets that are in it are 92 front and back.

Better rich than lean at first , get a Holley jet kit / assortment / should be the same for ProSystem Jet kit on ebay or wherever so you can get it in the ballpark so it does not end up costing you a bunch of money to get the right jet/s sizes , also some Holley jets are the same size for the number stamped on them but #92 are like 105 , do a search for Holley Jet Sizes and you will get the chart under "images" how rich is rich? try primary first , I would guess a #84 to start with , it depends on a lot of stuff cam choice makes a big difference but nobody can give you an exact size for your engine , good luck.

#92 is a 105 drill size
#84 is a 99 drill size
#79 is a 91 drill size
#74 is a 84 drill size
#71 is a 76 drill size
#70 is a 73 drill size

Does the carb have power valves in it? If it does make sure the throttle linkage is adjusted so it is on the idle circuit only and not up on the transition circuit when idling You may need to adjust the idle screws in so it has from 1/8 to 3/4 turn out from bottom with the linkaged on the idle circuits only on all the idle screws The jet sizes should not influence the idle air fuel ratio There are four or five different circuits in both the primary and secondary parts of the carbs. depending on if it has both four corner idle and power valves in both ends of the carb.
Good luck. let us know what you find and do, that will help others on here later

Add idle timing, leave total timing where it is. It will take more fuel with more timing.

I am running 94's in my 1000 on my 512...Also, what idle bleeds are in it and HS bleeds are in it. You should have #70 idle bleeds, and #27-32 HS bleeds...I run the #27-#28's and it is dead on.

How do you know the the primary main circuit is way too rich?

Idle bleeds are #76 and the HS bleeds are #32.
I'll add more idle timing and see what it does. Thanks for the suggestion!

Change idle bleeds to #70-#71 too...Then start working the HS bleeds down while watching plugs.