1969 Z/28 Holley 4053 DZ questions

[LeadFoot_69_Z/28]

I have a 1969 Z/28 with a build date of April, 3rd week, 1969.

I have a 4053 dated 924 (8 weeks previous) and 941 (2 weeks previous).

Is the 941 the perfect date for an April, 3rd week, 1969 Z/28?  I have read that 3 - 6 weeks is the best.  Is 2 weeks previous (941) too early?

Please look at these 4519 and 5583 metering blocks (below). See how the castings are different in each picture?





Which one is correct?  Why are they different if they both are stamped 4519 and 5583?

[hotrod68]

I'd guess that's just a Holley casting mark anomaly, Lead. Holley made a blue million metering blocks! I'd think the important thing woiuld be the DZ on the choke horn. Can they actually trace the metering blocks to a specific carburetor?

[KurtS]

Go with the closer one. Remember that was the build date of the body, car was completed several days later.

[JohnZ]

The "circles" are ejector pin pads, where slides pushed on the casting to eject it from the die-cast mold; they have no functional effect at all.

[jdv69z]

My 10B, Oct '68, build date Z has a caburetor mfg date of 872; a lot closer to 8 weeks than 2.

Jimmy V

[firstgenaddict]

I would think that the early cars would have carbs spaced out futrther than the later cars just because of ramping up production.