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Old 06-16-2006, 06:40 PM   #20
Rev
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Join Date: Nov 1998
Location: Houston, Tx.
Posts: 3,887
Default Re: Holley carb. gurus needed!

I use a CC 268EXE (224/230@ .050) which replaced a CC 268HE (218/218 @ .050). That's a little milder than your's but not too much. At the same time that I changed the cam, I went from an Edelbrock Performer to a Performer RPM Air Gap intake manifold.

To make a long story short, I ended up almost completely recalibrating the carb (Road Demon 625) to make things work correctly. I had to rejet the mains larger, add a 50cc. accelerator pump, change the accelerator pump squirters (smaller or larger, I can't remember), go to a lower # power valve (4.5 in.HG), enlarge the power valve restrictor channels, and finally enlarge the low speed air bleeds.

All this took a couple of months of experimenting. I couldn't have done it without reading and rereading my Holley book several times. The car now "barn storms" from off idle to 6000 rpm red line with nary a hiccup. At times, I wondered if I would ever get it right, but I finally did.

The tech dept. at Barry Grant was no help at all. They just told me I had the wrong carb and to buy the correct new one. When I asked them about altering the one I had, they just said I was going to ruin it and to leave the calibrating to them. I'm now glad that I didn't listen to them (saved me several hundred bucks).

Well that's how it went for me, good luck with yours.

And lest I forget, I had to go from a TCI 2500 stall convertor to a TCI 3000 stall convertor to match up with my new power band.

Rev
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'66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi.

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