Howdy Scotts68:
The Holley 2300 comes in both new and rebuilt form as a 350 and as a 500. THe numbers supposedly indicate CFM. If that is true it is likely using the V8 formula. Compared to the one barrel formula that would represent 250 & 357 cfm respectively. For a stock or mildly modified 200s the Holley 350 would be very adequate and a nice upgrade from a stock '68 Autolite 1100. I would improve performance, driveability and possibly economy.
There are a number of builder Holley two barrels available through swap meets that only require a rebuild, cleaning and a kit to be usable. Just make sure the throttle shaft is tight in its hole to keep costs down. The hard part is figuring out what it came on originally to help out the parts counter guy when ordering a rebuild kit.
Ironically, the 500 is usually cheaper, but only comes in manual choke and is the one usually used for circle track racers who are limited to one 2 barrel carb, so they are plumbed and jetted richer.
The Weber DGES is rated at 360 cfm, and John's price is greatly discounted from most retail sources. Clifford has an adaptor for the Weber's too. You may be close on hood clearance in either case. If possible, remove the stock carb adapter before mounting the 2 barrel adapter.
In addition to the 2 barrel adapter, you will need to modify the linkage, or better yet convert to a throttle cable and pedal. You will need to reroute the fuel line slightly and you will need to upgrade to a low profile, air cleaner for this carb mouth. I used a low profile unit from an '83 LTD that had a cold air inlet system. The Holley will have a ported vacuum source for your distributor. I don't believe the Weber will. In that case use manifold vacuum or mechanical advance only, but increase the initial advance setting.
Adios, David
