66 Carb HELP!

[Tom L.]

On my 66 BB I have a 3247 carb (model 4150 780 CFM) and recently disassembled it to rebuild. The jets seem abit weird to me--the primary jets are #80 & #82 and the secondaries are #78 & #82? Shouldn't they all be the same? And, to further complicate things, I didn't log which jets came from what ports? Should the 82's be on the same side (choke side or throttle lever side)?????

Any assistance would be appreciated.

Tom

[William C.]

Re: 66 Carb HELP!

Per both my memory an my trusty Parts manual, the original jet sizes are #70 primary side and 76 secondary side. At least that is wher I would start, Gas today is different than in '66, but the Primary/secondary stagger should stay about the same.

[Timothy B.]

Re: 66 Carb HELP!

I am pretty sure the L-88 had a stagger jet set up from the factory, I don't know about the 3247 Holley. Does the engine have a stock camshaft because if not someone may have tuned the carburetor because some longer intake manifold runners are leaner than the shorter ones.

I agree with Bill, set it up the to the factory specs and see how it runs.

[William C.]

Re: 66 Carb HELP!

3247 NO stagger side to side, just primary (2) and secondary (2) jets.

[Dick W.]

Re: 66 Carb HELP!

3247 NO stagger side to side, just primary (2) and secondary (2) jets.

Believe stagger started with the 4296, used on the later '69 L/88 engines

[Ralph B.]

Re: 66 Carb HELP!

Per both my memory an my trusty Parts manual, the original jet sizes are #70 primary side and 76 secondary side. At least that is wher I would start, Gas today is different than in '66, but the Primary/secondary stagger should stay about the same.

Bill is correct with the model 3247 jetting @ 70 primary and 76 secondary with NO side to side stagger.

For some reason the previous owner of my 66 w/model 3247 staggered both the primary and secondary jets (side to side) as well ----- not sure how you go about making that decision, other than reading the plugs ??? Anyway I removed the side to side stagger and went with 68 primary and 74 secondary which is slightly leaner than original Holley settings whereas my driving will be limited to short distances only.

The jetting you currently have seems strange --- IMO way too rich for the primaries.

Also you should check your power valves to make sure they are appropriate size consistent with your manifold vacuum ----- this is important and easy to do.

Good Luck,
Ralph

[Timothy B.]

Re: 66 Carb HELP!

I think all these Holley's are jetted on the safe side (rich) from the factory, there is much to gain from tuning the carburetor as well as the timing.

[Carl B.]

Re: 66 Carb HELP!

Been a while since I did my carb (4150/3247) I googled holly web site and found listing For jets and power valves and other useful info hope this helps