The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 4 hole carb spacer for better signal, will it work?

Mrturner1 · 07-05-2016, 01:09 AM

Ok I got an MSD pro billet HEI today and installed that so all my timing and spark issues are gone. I decided to try a smaller power valve since the one that came with it was a 6.5. I tried a 4.5 and the stumble got worse. I can't imagine needing a bigger power valve, but I'm certainly no expert. Timing is 18 initial, 18 mechanical in at 3000 rpm, and the instructions say the vacuum advance puts in 10*. I tried both ported and manifold vacuum and BOTH make the truck idle up when I connect it.

07-05-2016, 01:09 AM	#20
Mrturner1 Registered User Join Date: Nov 2015 Location: Colfax California Posts: 1,644	Re: 4 hole carb spacer for better signal, will it work? Ok I got an MSD pro billet HEI today and installed that so all my timing and spark issues are gone. I decided to try a smaller power valve since the one that came with it was a 6.5. I tried a 4.5 and the stumble got worse. I can't imagine needing a bigger power valve, but I'm certainly no expert. Timing is 18 initial, 18 mechanical in at 3000 rpm, and the instructions say the vacuum advance puts in 10*. I tried both ported and manifold vacuum and BOTH make the truck idle up when I connect it.