Is the power valve different on the 715 vs other Holleys? I know there are different gaskets to use, but when I changed out my power valve for the one in my kit, it didn't run very well. I put the old one back in. I don't know if the one in there now is original, but I do know it has been in there since 72. Is there a certain kit number for the 715? Thanks for any info. TommyJ 66 GT350
The original power valve for a 3259 Holley is number 85, i.e. it opens at 8.5 inches of mercury vacuum. All kits I have seen includes either 65 or 75 power valves. Also, one of the largest carb restorers installed a 55 in my 3259 during rebuild. The car ran like a bear. If I were you I would buy a 85 power valve and make sure the float levels are according to spec. Please note that the 85 only applies for cars with original camshafts. Texas Swede
I ran into the same problem a few years ago. Not sure if there is a difference in the kits but I found that my motor had a different vacuum than the one that came in the kit I purchased. I bought the correct power valve that operated within the range my motor had and it corrected the problem.
Two quick comments 1) Because of lots of variables possible in engine set ups my best practice is get a long section of vacuum hose and temporarily have a gauge in the car to check system vacuum under the conditions you drive under. Once you find what normal is you buy a valve that stays closed until you want it open, i.e. you don't need full enrichment unless rpm and load require it. 2) Modern service parts, even those sold by the OEM, are often not very good. In the last several years I inspect and leak check them all. I serviced a carburetor for a 1969 Boss 302 a few years ago and the valve in the OE kit was junk (would never seal). It took a total of four new OE valves to find one that didn't leak. Now when I get a kit I also get at least two extra valves at the same time so I can prevent multiple trips to town chasing a good part. Dan
