Help in reading jet size
 

I removed one jet to check it’s size and I’m not clear on how to read it on the side it has 612 but the 2 is up side down so is it a 61 jet or a 612 jet I looked in the Holley web site and the carb came through with either one

Re: Help in reading jet size
 

"Size wise" it's a 61. The upside down 2 is a revision of sorts. I forget exactly what they did to the 2nd version, but what you got there is a size 61 "version 2" type thing.

Re: Help in reading jet size
 

thanks i want to try a different size

Re: Help in reading jet size
 

The 1-2-3 refers to the tolerance of the jet. Each jet is measured and compared to its theoretical perfect sizing. Don't quote me on this, but I think 1 is towards the low limit and 3 towards the high limit on the machining tolerances. Therefore, if you're trying to assemble a set of real close tolerance jets, you'd try to put all '1' in your jet kit. I seem to remember reading about this either on the Holley site or in one of my carb tuning books.

Re: Help in reading jet size
 

They used to just refer to them as "close tolerance" jets that cost a liitle more $$$. Now do they have 3 tolerance levels, LOL. I'm really just asking?

Rev

Re: Help in reading jet size
 

I seem to remember reading this somewhere. Will try to find the article/book and clarify but this is how I remember it. I've been wrong before though so don't go out buying all #1's !