Which Kit?

[machyoung]

I have an older Holley 4160. It's a 3310. Not a 3310 anything, just a plain old 3310. The carb is the old 3878261-EH. When looking at the Holley chart, it does not list a renew kit for the application. If it were a 3310-1 and I have a feeling that it's how they listed it, says to use a 37-1539 kit to rebuild. This kit is over $100. If this was any other 3310-x, it uses a 37-754 kit which is $30. Any ideas?

[Gaz64]

Early 3310s are 4150 with a secondary metering block, then 3310-1 onward became 4160s.
The 37-754 kit should do, but you will need another metering block gasket.
The 37-1539 is a trick kit, not just a Renew Kit, and contains tuning parts such as pump nozzles, cams power valves, etc.

[machyoung]

Understood, however, I'm saying that the list number is 3310. Early or not it is a 4160. No secondary metering block. Why can I not find a kit listed for a 3310?

[Gaz64]

This is a 3310 like yours with a secondary metering block: https://www.ebay.com/itm/1965-CHEVEL...-/323799480486. If yours truly is a 4160 without a secondary metering block, then the 37-754 will suffice. Gary

[machyoung]

Thanks Gary! That is my carb exactly excepting secondary metering block and my date code is a little earlier at 914. I'll buy the 37-754. Thanks again, Robert

[Gaz64]

You're welcome Robert. Gary

[machyoung]

If we could please revisit. I've rebuilt and upgraded with secondary metering block to a 4150 style. I'd like to know the basic transfer slot setup prior to installing. .020" on the primary transfer slots? Anything on the secondary? Thanks.

[Gaz64]

Aim for about the same or slightly less exposure on the secondary. The secondary throttle shaft needs for be slightly more "free" to rotate, so it doesn't bind; needs to be checked after the carb baseplate is torqued to the manifold. Avoid thick gaskets without limiting spacers on the mounting holes. Gary

[SatherCS]

I thought the transfer slots on the secondary were placed higher in the bore? I don't think you'd have any transfer slot showing on the secondary unless you really needed it to bring the primaries into spec.

[Gaz64]

Yes, from memory that is correct.
The secondary side has smaller constant feed discharge holes, (non-adjustable idle circuit).
The amount that you wish to crack the secondaries open for additional airflow depends on engine capacity, cam profile etc.
You can always remove the factory screw from the bottom, and refit from the top, a lot easier to adjust on car. Gary

[machyoung]

So what I'm looking for is an initial setup. Primary & secondary throttle plate position. .020" on the primary and match the amount opened on the secondary?
Engine is a Ford FE, 10:1, Comp 282S cam, Edelbrock heads & intake, headers, etc. About 11-12 inHg vacuum at 750 RPM. What I'm trying accomplish is getting the idle & cruise AFRs set.

[Gaz64]

It isn't that critical.
Hold the throttle up to the light, and make the secondary just short of the primary.
This is a vacuum secondary carb, two corner idle, and no replaceable bleeds.
It pulls fairly good vacuum, I would be more concerned if the camshaft was larger. Gary

[machyoung]

Time to revisit.

AF ratios as follows; 13.5-14.0 @ idle. 13.5 @ cruise. However 15.5-16 @ WOT. Primary jets are 72 and secondary are 78. I have also removed the ball bearing from the vacuum secondary diaphragm (secondaries now just seem to flop open with taller yellow spring). Does this affect the AFR? I'm going to return the ball bearing to it's rightful home. Ideas? Jet up secondary? How much? Thanks, Robert.

[Gaz64]

Wide open is engine destroying lean if that is correct.
What are using to determine that A/F ratio?
Have you looked at your spark plugs?
What size fuel line?
What fuel pump, filters, etc?
Yes, a too early, flopping opening secondary gives a lean bog. The engine struggles to pull fuel if the venturi signals are weak.

[machyoung]

Wide open is engine destroying lean if that is correct. Yep!
What are using to determine that A/F ratio? Innovate AFR meter bung just past header collector.
Have you looked at your spark plugs? No.
What size fuel line? 3/8"
What fuel pump, filters, etc? Holley manual through Holley regulator set @ 6-7 lbs.
Yes, a too early, flopping opening secondary gives a lean bog. The engine struggles to pull fuel if the venturi signals are weak. Is it the small or large ball bearing? I will replace.
Thanks so much for your responses.