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393 Posts
Demon carb

I was running a Demon 650 DP mech sec on a 302 with Winsor Jr ported and polished heads (1.94I/1.6E), X303 cam, Victor Jr intake ported to heads 1262 intake port.

I felt I never really got the tune right on the carb, wasn't sure I could blame it on the carb. I rebuilt the sucker and replaced the power valve up to a 10hg unit to finally get a smooth transition. During the rebuild I found TWO porosity spots in the aluminum that I had to plug up!! Urgh poor quality!!

It seems to me that the accelarator pump didn't squirt clean and left raw un atomized fuel to pool. You could see it trickle out after a throttle burp. My pistons always looked horrible after just a few runs and street time (about 10 pulls and 1000 miles).

I use a A/F ratio gage in my car, I could get it to stay in the proper zone and the plugs looked good, so I assume that I was having drop out due to the big cam, intake, heads on a small CI engine turning low RPM's on the street.

Having never run anything else on this engine I couldn't tell you Holley vs. Demon. I can tell you this, MAN oh man once the R's got up to 4K to about 7K hold the heck on, boy was it fun~! Can't wait to get my 377 running, think a month or two out now, I will put the same carb on it and see how she does.:happyhapp
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