<VV> Best 2-Carb Setup

[Larry Forman]

On 12/31/2010 8:44 AM, BobHelt at aol.com wrote:
> And stay away from HV carb mods too, since all of the suggested
> mods LOWER the low speed performance by adding high-speed air flow capability
> (  that's what adding to the venturi size does).
> Regards,
> Bob Helt
While I consider Bob one of the Corvair carb experts, I would still make 
a few minor carb performance changes to the standard HV carbs.   One of 
my favorites is to shorten the accelerator pump arm linkage connections 
by one-half inch.   It will give much better accelerator pump shot and 
help give a little extra boost on acceleration.   I like to replace the 
carb inlet valve with one of the stainless steel ball inlet valves.   
Those better valves improve the carb refill rate, especially if the 
input port has been opened up a little for better flow.  That way the 
carb stays closer to the full bowl level and everything seems to work 
better.   I replace the sintered bronze carb "filter" with a cleanable 
stainless steel mesh that does not seem to get plugged up as easily and 
is quick to clean for better flow.   Also, while this is not a carb mod, 
I find that most of the distributor vacuum advance canister internal 
springs have gotten weak over the last 40 years or so.   So I make my 
standard mod to take 9/16" and 5/8" deep sockets and dimple the nipple 
end of the advance can to restore the original vacuum point for initial 
pull-in of the vacuum advance lever.  The lever should not start pulling 
in until about 8-10 inches of vacuum, as I recall.   If it starts to 
pull in around 5-6 inches of vacuum, then the internal spring needs 
compressing.

I use a Dwyer Magnahelix differential vacuum gauge for balancing the 
carbs.   Since this uses the carbs as the venturi and connects to the 
vacuum choke pulloff ports, the air cleaners remain in place.    You can 
adjust the carb balancing linkage for best balance during acceleration 
and not necessarily just for idle.    So you balance the carbs for best 
acceleration considering any differential contribution from acceleration 
pump squirts.

Larry