Holley needle valves!!

[limeyboy]

Rebuilt my Holley yesterday and the rear bowl had a "normal" 3 piece needle and seat but the front bowl has a one piece "This solid type of needle & seat was used on some industrial and truck applications" one fitted!
My rebuild kit had 2 "normal" ones so I had to put the solid one back in, can anyone suggest why I've both types and where can I get a replacement for the solid one?
I forgot to say I can't swop it for the normal one as the solid one has a larger dia thread.
Someone changed the front bowl at some time?
Thanks

 

[camachinist]

I haven't run across that. Perhaps a picture could help. This is what I'm used to seeing on 4150's, etc. There are different setups for the 4165, etc carbs but I don't recall if bowls can be swapped or not.

 

[limeyboy]

Yes, the ones you show are in the rear bowl but the front one is one piece and larger dia.
I've got one coming from NJ with some other washers etc and think it will do.
I'm not sure but i think they come from a non-car carb.