Mystery Holley Jets. What size?

[Tim_K]

A guy I know was throwing out a couple of mid-70's Holley 2 bbls, like you'd find on a stock 360 or 400. So before he did, I took the jets out of them.

One carb had 2 different jets, numbered 571 and 611. No big mystery there. a #57 jet and a #61 jet, both on the tight side of the flow specs for #57's and #61's.

BUT - the other carb had 2 jets, both were numbered 299. And the 299 was stamped upside down. Visually, the hole size appears to be about the same as a #64 Holley jet, but I also know that because of entry and exit tapers, as well as the length of the hole, Holley jets of the same diameter can have different flow specs.

The #299 jet had an entry taper that the #64 did not.

So what are these #299 jets equal to in the standard 2 digit Holley numbering system?

[pishta]

the 124-299 jet is a 2 barrel or a funky 5210 4 barrel jet equal to a 122-57. The shape is indeed different due to the carb design. The 124-299 and the 122-57 both use a .056 drill bit. If the jet is a 122-xx2 then it is a close limit jet.

[Tim_K]

Ok, thanks. Now I know those #57 equivalent jets are too small for me to use. I know that on close limit jets, the third number is a 1,2, or 3 to show that the jet is on the low, middle, or high end of the range for that size jet.