[DanEC]

I'm upgrading (sort of a loose term) my generic Holley 1850s with exterior adjustable fuel bowls and going through adjustments on them. The stock jetting was #65s and they have a #9 stamped secondary plates which I think equates to a .067" fuel orifice.

Motor is a stroked 428 with 427 LR dual quad intake, steel heads, medium flat tappet hydraulic cam.

Most of the Holley literature indicates #66 jets in many of the 1850 carbs. Since I run 93 Premium Ethanol and have a pretty free flowing exhaust system I was thinking it might be a good idea to go up to the #66 jets from the #65s. But - no real basis behind thinking of doing so.

Anyone play around with these 1850s on a dual quad FE at the strip or on a dyno to have an opinion or recommendation on this? Engine was built by KC and broke in on his dyno but they didn't try to do any real dyno tuning with it. Pretty sure carbs were not touched other than idle mixtures. Hard to figure A/F data on it as they only used a hood on one carb for air flow measurements.