Ricky, I don't have all those numbers memorized, and the numbers I used to have memorized are fading......Basically I'm saying the only thing I remember is that I don't remember anymore.
With that said I would search the web for the specific casting and part numbers on the carbs you have, looking specifically for some factory use proof giving rise to these two carbs being something rare and special, much like a 735 CFM Holley as used on a dual quad shelby 428 from a 4spd GT-500.
The specific part numbers and factory application can have significant impact on the value of a carb.
If you find these are just off the shelf 400 CFM Holleys anyone could have purchased from any store then you have two Holley carbs that must be looked at from a useful point of view.
What is the overall condition?
Any modifications to the carb beyond bolt on tuning parts...like altering the PVCR?
What do the carbs need?
How much would it cost to do a full rebuild or full restoration if they were once green zinc coated like older Holleys?
Because you have a box of parts of old Holley carbs you present MANY, MANY questions to most potential buyers and this will keep any higher valuations away because the buyers must take a big risk in buying your box of parts.
Keep in mind those carbs may have been improperly modified at some point, or directly damaged like having warped base plates (in the eyes of potential buyers) so they may purchase a box of parts rather than potential full carbs to be assembled and used.
Disregarding any factory type high values I would say these represent around $150-$200 worth of parts total at this point because nothing is certain with any of the parts.
If they were rebuilt by a compentent tech they move into the fully assembled and functional category, but still come with some questions because the buyer does not know if they actually work...that part is assumed based on visual condition and descriptions. Remember, everyone on eBay is selling a perfect whatever.
If you can get them rebuilt and tested, like video of them being used on an engine either on a dyno or in a vehicle, then you have fully working carbs and the value goes up a bit more.
At the top of the mark I suspect you would be hard pressed to get $300 each for these carbs....Maybe $400 if they were proven and in perfect condition.
New 400ish CFM Holleys are around $500-$700 at Summit.
Good luck.
