what carb to build

[BAMiller]

I need to build a carb for a 1981 Z28 I'm building. It's a 30 over 350 Chevy 9.7 to 1 compression with Vortec heads and a GM Roller cam they put in crate engines. Part #10185071 duration at .050 208/221 and lift .474/.510 112 lobe centerline. I have two good cores available a 17059216 and a 17085213. The first one is the 750-CFM model, and the second one is an 800-cfm model. Both have APT and idle bypass air. Is there any advantage to building one over the other? The car is just a driver with no plans for racing of any kind. Thanks

[Kenth]

https://cliffshighperformance.com/simplemachinesforum/index.php?topic=4486.0

I would start with the 17059216 for the above reasons.

HTH

[BAMiller]

Thanks, I'm glad I posted this I was leaning towards the 17085213. I did not notice that plug on the back. I did think it was odd the primary metering rods were .062 at the top of the taper. I will put it back together and put it back on the shelf. I think the 17059216 may be in better shape anyway.
With my engine combo should I use recipe 1 or 2? Thanks again

[novadude]

Something to note about the 17059216...

If my memory is correct, this carb does not have provisions for a ported vacuum source.  If that is something that important to you, you may want to look closely before putting a bunch of time and money into that carb.  From what I recall, they have an EGR port slot that looks like it could be a ported source, but these have a bleed hole above that will not allow it to work properly as a ported vacuum advance source (unless the bleed hole is plugged).

[Kenth]

I use to thread the EGR bleed off hole for a 2-56 set screw, if a ported source for ignition vacuum advance is needed.

[BAMiller]

Is the bleed hole in the baseplate?

[Kenth]

Yes, next to the slot in passenger side primary bore.

[novadude]

I use to thread the EGR bleed off hole for a 2-56 set screw, if a ported source for ignition vacuum advance is needed.

That's a good solution.