Amazing...that someone would spend huge money, time and effort for a one-off engine redesign only to cage a trophy (no $) and bragging rights! Geez, a turbo on any modern engine would surpass this old flathead design for sure.

Quote from: Mark Bliss on August 27, 2023, 12:57:21 PM

Thanks to both of you, and so far- agreed.
And my vague description of "cleaning and freshening it up" I did mean a soft parts kit.

My intention is to return to the original jetting to start- per the Holley specs. ("out of the box wouldn't specifically apply, as I got it used sometime in the 70's)

As I recall it, the general consensus (and my own experiences) left me inclined to think "universal" models were often jetted safe, and I often ended up leaning them out 1 or 2 jet sizes. While OE specific models were often closer.
This is a (I think its 33100?) that research describes being originally used on a 69' Chebby 396, not that it means anything.

Another related question- When I last messed with this I was planning a track day and wanted to try a 1" spacer. I have since decided that was likely either a mistake or wasted effort on this dual plane manifold and not likely to give the slight top end MPH bump I might have hoped for.
When setting that up, I recall checking the throttle for fully opening at WOT. Not paying close attention, I made an adjustment that as it turns out- causes my lead foot to open the throttle past WOT by perhaps 15% or so, as there is no real built in stop at full open.
Is it common to acquire or fabricate something for this condition?

BTW, it may be common knowledge to others, but on these vac secondary carbs, it is quite possible that opening the primaries 115% and having the secondaries open fully the link rod can drop down in its slot and upon throttle release, jam the secondaries wide open.
Guess how I know...

Holley has made at least a dozen versions of the “3310”, they are up to at least 3310-11 so far, plus more sub variants. The early ones had a secondary metering block, then Holley went to secondary metering plates, without a power valve. Add into that differences between down leg boosters & straight leg, internal passage differences, air bleed changes, etc. Always best to be sure of the exact version you have. And of course only the original version with date codes during car production were used on the actual Ch**y applications, so the vast majority, even of the early ones were just aftermarket.

Any 3310 SHOULD have a positive stop to keep from going past full throttle. I’ve included a picture showing the arm and how it contacts the base. Check yours over carefully - it maybe has been modified, or is broken. But that could be very dangerous. Replacement throttle arms are available if there’s a problem with yours. You can get add-on mechanical throttle stops too, I think Moroso still makes one. They’re not a bad idea to keep from bending/breaking the throttle arm on the carb. We use them sometimes when bracket racing to adjust ET, but they’re not a bad idea just from the safety aspect.