I never like the Holley Vacuum Secondary setup, as there is no direct control of it. I like manual secondaries, and that's one reason I like the Edelbrock carbs on STREET engines. I like the fact that (aside from better fuel mileage than a Holley) even though the secondaries have an 'air valve' like a Q-jet, they are indeed manually controlled. When you stick your foot in it, you KNOW the 4bbl is 'kicked in'.bigjoe1 wrote:I drove this truck many times, and the manual secondarys are the secret.. You can open the secondaries just a little, because you can feel the linkage with your foot.. It would scream up a big hill with a car on the trailor, and you never had to push the carb wide open.. I have told several other people about this, and when they tried it, they could not believe how good it works. Most people would never even thing to try it, but it really works good
JOE SHERMAN RACING
Too many Vacuum Holleys quit working without you knowing it because of ripped diaphragms or leaks. They also don't usually open all the way. Plus, most of Holley's 'generic' vacuum carbs like the 1850 and 3310 that are priced comparably with the E-boks use those crappy secondary plates instead of a real metering block that the jets can be changed in. I LIKE the metering rods in a E-bok, as the ENTIRE fuel curve through all throttle positions can be tuned. They don't just use a 'power valve' that simply dumps extra fuel at a pre-determined vacuum level. The E-bok is much more precise and fuel efficient. Sure, you -might- give up possibly 10hp on the top end compared to a 'race' carb, but gain it back in what really matters on the street. Plus, I don't think any of the 'generic' 600 and 750 vacuum Holleys that are in the same price range are going to make any more power. Maybe less.
Sorry for the rambling. Thanks for all the info on truck/tow cams!