Carburetor Questions

[LIRacer]

My 70 LT-1 has a Holley double feed on it. No auto choke mech which starting a little bit of a chore. As part of the spare parts that came with it, I was told the original carb was included. The spare looks freshly rebuilt. I can not find the proper number on it. The one installed is a mechanical secondary car. The spare "original " has vacuum secondaries. The Original has the number 6335 and 6145. Neither has the correct 4150 number. Any suggestions? Did the factory Holley LT-1 have vacuum or mechanical actuated secondaries?

 

[Crimson Thunder]

The LT-1 came with vacuum secondaries. Part #R4489 or R4555.