This weekend I installed the Holley 850 square bore, center squirt carburetor to replace the 800 spreadbore I had before. Not knowing the history of the carburetor (it was supposedly rebuilt), I was taking a chance making the necessary modifications to make a questionable carburetor work, but what the heck...
A few things I had to do> First, when I rested the carb on the intake, I found the accelerator pump was hitting the front of the manifold mounting area, so in order to set the carburetor flat, I had to grind out a little area about the width of the accelerator pump.
With the carb sitting flat, I wanted to put a double return spring on (where I previously had a real long single spring) so I had to fabricate up a bracket to hold the spring on the front end of the carb. With a little flat stock, some drilling, bending, and grinding, that problem was solved.
The feed line from the carb opened up in a different location than the carb from before, so I had to get a longer section of fuel line, and also replace the dirty fuel filter.
Since there's no opening at the base of this "new" carb for any PCV vacuum line, I removed the PCV from the passenger's side valve cover, and had to buy a breather to replace it.
Besides having to move the mounting studs for the carb outward, and making a longer air filter mounting stud, the fab was over.
The carb started the car pretty easily and without hassle, but the first time I cracked the throttle where the secondaries opened even a little, the motor started racing so I shut it off. The secondaries were POURING gas in (ie the float was stuck). I removed the rear bowl to find it was full of dirt!! Dried up, crusty dirt. So I cleaned the mud out of both the rear and front bowls and tried again.
This time it ran much smoother and I was able to adjust the idle while in neutral. I'll have to get a helper to help adjust it while in gear though, as it's still a little rough under load. It does sound good and crisp while revving though, so I'm sure it will be good.
Some pics:
-BP