I have a 66 coupe with a 300 hp 327 I am rebuilding a carb (3367) holley can any one tell me what size main jets were in this carb from the factory

 

I want to say 66 in the front and 72 in the rear, if you converted the rear plate to a block, that is

 

The 3367 only has primary jets the secondary is just a block

 

yeah, but you can add the secondary metering block to the carb to allow the use of jets in the rear............

I even added 4 corner idle to my 3367

 

The 3367 uses 66 primary jets and a #22 secondary metering plate - it does not have a metering block on the secondary side. Primary accel pump shooter size is .025, and it uses a very conservative "purple" secondary diaphragm spring.

The secondary plate actually works pretty good on those carbs, and WOT mixture can be effectively controlled and changed with primary jetting: Primary jetting has little effect on cruise mixture since almost all of the fuel metered at light cruise is metered through the idle and transition circuits - not through the main metering system. Cruise mixture can be effectively changed by changes to the IFR and low speed air bleeds, allowing the primary jetting to control WOT mixture.

If you should elect, for whatever reason, to change the secondary side over to a metering block, run the secondary jetting 8 sizes larger than the primary side, assuming you do not use a power valve in the secondary block.

A good level of tune on that carb is to bump the primary jetting up about 2 sizes, run float levels right at the bottom of the sight holes, crack your secondary idle open far enough to allow less than .020" exposure of the primary transition slots at idle, and use the long "yellow" spring in the secondary diaphragm. This will give you an outstanding level of performance with minimal effort and cost.

Lars

 

A 3367 had 65 primary main jets from the factory. The power valve was an 8.5. It had a 4743 metering block and a #22 secondary metering plate just like the 3810 for 1967. The 67 carbs used a 6.5 power valve for the small blocks.

Jerry Fuccillo

 

Anyone know if the 1966 350HP 327 had the same jetting and metering plate?

 

Same as what? You forgot half of your question.

 

The 1966 300hp 327

 

Yes. The 300hp and 350hp engines both used the same identical 3367 carburetor.

 

Thanks JohnZ and previous posters.