If so, can you tell me what size jets and power valves you are using? I took mine apart (list #4777) and it was shipped with 67's on the primary side, 73's on the secondary side, and a 5.0 power valve. I'm wondering which way to go when I start strip tuning. Aren't those jet sizes a little small?

Those are stock jets. I run one on my daily driver. Ended up at 67/74 w/5.5 pv.

If you have a cam with any size to it, you may need to go up. However, a couple sizes is probably about all. Don't forget that in a Holley carb, the jets set the cruise mixture. Your gas mileage will go down as the jet size goes up.

If you jet for the best mph, you can have the PVCR's in the metering blocks modified to provide that mixture with smaller jets. That way you'll have the correct WOT mixture and still have the best gas mileage you can get.

Good info, thanks guys

I have the same carb... on a low comp 350. Stock 2.02 iron heads and an XE284 cam. 4 speed with 4.66 rear gear. I also ran a best of 13.54 @104 mph just 2 days ago.

My previous best was 13.80 @102. The only change I made was to reduce the jets back to the original 67-73. That's what my engine seems to like. And a 4.5 powervalve.

I tried various jets and powervalves, and the stock jets seem to make the most sauce for me. I only had to reduce the powervalve due to my low idle vacuum.

chris

I found some info in an old Holley book that said the primary side may never need changing if you have the right size carb. If you run an MSD box you will think its lean so tune for mph and don't worry about the white plugs.

I run mine stock straight out the box. It comes with 67 primaries and 73 secondaries and a 5.0 power valve.