'67 L-79 Holley Questions...

[Bob S.]

Hello - From the carb air horn markings, my '67 has what appears to be its original "List 3810" carb with the 7 digit GM p/n and a date code that preceeds assembly by 2-3 weeks.

I'm curious about the "3810" also stamped into the left front baseplate/throttle body surface. Is this normal/correct? Maybe I've just never noticed this before.....or maybe the baseplate on the original "3367" carb from my '66 L-79 (which doesn't have a "3367" baseplate stamping) has been replaced??

Also, could someone please recommend a source of all the proper assembly torques for Holleys?

Thanks,
Bob S.

[Timothy B.]

Re: '67 L-79 Holley Questions...

Hi Bob,

My 67 has a service dated 3810 of the 1976 variety and the metering block is stamped 3810 as well as the base plate. Others with originals will answer you question for certain.

I can't give the torque values except to say there are in inch pounds. What's critical is the surfaces be flat for the new gaskets. I had to take mine to a machine shop to have the bottom and front/back milled.

[Jim T.]

Re: '67 L-79 Holley Questions...

This taken from my Holley installation and adjustment instructions.

Tightening of carburetor fuel bowl screws should provide 25-30 in.lbs. of torque. Periodically recheck bowl screw torque to assure proper fuel metering. Inadequate bowl screw torque is often characterized by a condition similar to a defective power valve.

[Gerard F.]

Re: '67 L-79 Holley Questions...

Original holley 3810's had 3810 stamped onthe base plate as well as the metering block in addition to the 4743 metering block number. Here's a base plate from a 751 (May 67) 3810:



Later replacements (later than Tim's) went to a generic baseplate without the stamping (and with a double choke pulloff vacuum port in the casting). The metering block number also changed in later rplacements (3608 comes to mind, but just off the top of my head.)

[Timothy B.]

Re: '67 L-79 Holley Questions...

Jerry,

The base plate on my 67 has only one vacuum port for choke pull off but I recall seeing a area where there is room for another port. It's flat against the base but I looks like it could be drilled and used. Is your original like that?

[Bob S.]

Re: Now '66 and '67 L-79 Holley Questions...

Thanks for the input guys!!

You've hit on another question I should have asked in my first post.....what do the stampings on my '67 metering block, "L18501", "8485" and "1947" mean, if anything, other than the fact it's a replacement?

Since the 3367 carb from my '66 does not have "3367" stamped in the baseplate is that a replacment too? Since I don't have a '66 JG, can I assume the '66 3367's correct metering block stamping is also "4743" (as mine has)?

I guess I hijacked my own thread to expand it from '67 to make it cover the '66 also......

Finally, other torques I can anticipate needing are for the baseplate assembly screws and for the (secondary) metering plate "clutch head" screws.......anyone know what these are? I know I'm being fussy about this, but since Holley component warping seems to happen often, and I already have 5 or 6 torque wrenches in my toolbox, why not use 'em?

Regards,
Bob

[Gerard F.]

Re: '67 L-79 Holley Questions...

Tim,

Original 3810 baseplates have only one port and and a boss for only one choke pulloff port. The replacements I've see have a boss for a second port that is not drilled next to the port,

Here's here's the baseplate of my 3810, prior to refurb:

[Gerard F.]

Re: Now '66 and '67 L-79 Holley Questions...

Bob,

Attached is general Holley Torque Chart:



Not sure if a 3367 has it stamped on the baseplate, probably not as the same baseplate casting was used for other carbs as well as the 3810;

Attached is my Holley Comparison chart, which compares the parts of other Holleys with a 3810. I used it to scrounge up replacement parts for my 3810 project.



Another way you tell if you have your original baseplate assembly is the single boss for the choke pulloff (shown in the post above), slotted (or even clutch headed) throttle plate screws (not phillips) and the primary throttle plate shaft bearings are leaky and worn. As the primary throttle shaft is probably the most physically used part on the carb, it is probably the reason to change the assembly and put on a replacement.

Have fun,

[Bob S.]

Re: Now '66 and '67 L-79 Holley Questions...

Another way you tell if you have your original baseplate assembly........................and the primary throttle plate shaft bearings are leaky and worn. As the primary throttle shaft is probably the most physically used part on the carb, it is probably the reason to change the assembly and put on a replacement.

Have fun,

Jerry - You're the man!!!! You guessed it...throttle shaft leaks: the #1 reason I'm getting ready to rebuild the 3810 for my '67! I've found a source that sells a kit to drill, ream and install bronze bushings in the throttle bore, and will probably try that if your/our suspicion of wear is true since the "3810" stamped baseplate appears to be the original. Although I may luck out and just need new throttle shaft seals.....a job I did about 30 years ago on my first '67 L-79.

Thanks for your help!!!!!

Bob

P.S. Jerry - I'm having trouble seeing the Holley comparison chart you posted. It loses clairity as soon as I try to enlarge it. Is there anything you could do to either post with greater resolution or maybe in a different format? I can just barely make out the torque specs though...

[Timothy B.]

Re: '67 L-79 Holley Questions...

Jerry,

I just looked and the base plate on my 3810 has another flat boss where a second vacuum take off could be drilled. No protrusion for hose hook up just the boss in the casting. FWIW

[Gerard F.]

Re: Now '66 and '67 L-79 Holley Questions...

Bob,

Try the one's below, I put them into a pdf format.

[Gerard F.]

Re: Now '66 and '67 L-79 Holley Questions...

Bob,

If you are just starting your 3810 overhaul you might consider this:



and:



I had both metering surfaces as well as the base of the body surface planed at a local machine shop.

If you do do this, make sure you check the straightness of the metering plate as well as the metering block, as they will warp with the warp of the body (which makes matters worse). My block was OK, but the #22 plate was warped or bent.

I was able to straighten the plate by putting it between two 3/8" plates (with holes in it to protect the little mounting studs) in a vise. I then shimed it in the high and low spots to reverse bend it. It came out pretty straight. Others have told me that they just beat them with a hammer to straighten them, but I'm a little more conservative

When I got ready to reassemble, I could not for the life of me find any of the teflon impregnated tape that they originally used on the throttle shafts. So I wound up buying a new baseplate assembly to finish the job, figuring on doing the baseplate in the future. The replacement baseplate remains on the car today. You know how those things go, on to other projects.

Here's my finished (or semi-finished project with the replacement baseplate):



It runs really well, but they notice the phillips throttle plate screws

[Randy R.]

Re: '67 L-79 Holley Questions...

Jerry,

Thank you for sharing this information with us. Coincidentally, I brought my carb to a machine shop on Friday to plane the surfaces of the main body.

Randy

[Bob S.]

Re: '67 L-79 Holley Questions...

Jerry / Timothy - Thanks for all your help.

In reviewing the Holley comparison sheet, I find it interesting how the 3810 and 3367 calibrations differ; most significantly the power valves and accelerator pump settings. It strikes me the '66 and '67 327's are likely 'indifferent' to the two different calibrations; especially considering each covers both the 300 and 350 hp ratings.

Timothy, I painted the wheel....it looks great!

Regards,
Bob S.

[Bob S.]

Re: '67 L-79 Holley Questions...

Jerry - When you say you couldn't find "any of the teflon impregnated tape that they originally used on the throttle shafts", were you referring to the throttle shaft seals?

Bob