Has anyone tried using "adjustable main jets" in a Stromberg 97 to be exact. Do they work well? or should I just get a few different sizes?  Thank's

I have used adjustable jets on the model 4150/4160 Holleys.  The problem with adjustable jets is getting them initially adjusted so they are actually in the ball park. While too rich can wear the rings and cylinder walls at a faster rate, being too lean can promote some very serious and detrimental engine damage so care must be taken when making those adjustments.  A wide band oxygen sensor would assist greatly in this.  Performing those adjustments by trial and error and simply looking at plug readings or seat of the pants performance would be guess work at best and involve a considerable amount of time and driving.  And where more than one adjustable jet is involved, then having them the same or balanced would be another problem.  If one had a chart that would correlate the number of turns of the adjustable jet to a corresponding area size, then tuning with those could be performed in a more educated manner.

For the multiple setup 94’sand 97’s, I simply use numbered jets. Once a baseline is determined, those numbers can be used on other engine combinations as a starting point.

Lorena, Texas (South of Waco)

Found a set at a swap meet once and gave them a try on my Holley 94 3x2, (only the primary).

They were just OK, not that hard to get close, but once they were there it was really no different than buying 3-4 jets in a range and seeing what it likes
I was really not scientific, just plug check, sound, smell, etc to figure lean/rich.

I eventually just upped the secondary jets to compensate for blocked power valve and left it alone.

Vintage mixers have enough inherent fiddling that 1 less variable was easier. JMO

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC