Holley Power Valves & carb ????

[Gary S.]

I am putting new gaskets in the Holley #3367 off of my 66 and I was wondering what is the suggested power valve for this car. The Holley rebuild kit comes with a 6.5 but the speed shop where I bought the kit gave me an 8.5 power valve and said it was closer to what was originally in there. I seem to remember reading a long time ago that a 6.5 was prefered for normal around town driving. Any comments? I don't race, autocross, or get into the gas (much) so I am looking for a sunny day type of driving. I know that the 8.5 will open earlier than a 6.5 but doesn't that assume that you will be getting more gas and more power sooner. I don't think that I will really need this 8.5.

I am open to opinions here.

Last comment, I found a very tiny piece of gasket material in one of the main metering jets when I disassembled the carb this morning. Am I correct in thinking that this small piece of material would be enough to cause the car to be real sluggish on acceleration but idle nicely, including rev-ing the engine up in the garage? I cleaned the material out and blew the passages out with carb cleaner and didn't find any more gasket material. Thanks again, as always. Gary 21316

[Ken Markusa]

Re: Holley Power Valves & carb ????

If you could hook up a temporary vacum gauge and drive around this could give you an idea as to what kind of part throttle vacum you have an 8.5 could make it run rich but every motor is a little different as are driving habits its a bit of trial and error. By the way what was in there before? and was it driving good before? Ken

[Gary S.]

Re: Holley Power Valves & carb ????

I had an aftermarket power valve in there before and it ran quite well. I KNOW - "if it ain't broke....." I was going to put new side bowl gaskets on and I thought that as long as I had it apart, why not put a Holley power valve in. The aftermarket P.V. doesn't have any markings on it so it is difficult to tell what it is. If I don't like either the 6.5 or 8.5 I can always put the old one in rather quickly. Gary

[motorman]

Re: Holley Power Valves & carb ????

the 3367 carb came with a 85 power valve. using a lower number power valve can cause a stumble at part throttle as the carb is lean at a certin point.

[Iron Duke NCRS #22045]

Re: Holley Power Valves & carb ????

I'll bet the price of a Grand Sport that the little piece of debris you found clogging the jet was the whole source of your problem.

Duke

[Gary S.]

Re: Holley Power Valves & carb ????

I pass on that bet, because I pulled the main metering jets, cleaned them and the passages, reset the floats and AWAY I WENT. It cruised just fine from 25 mph up to 70 mph. I AM learning as I go along here. I just wish I would quit learning from my mistakes and learn by reading instead.