<VV> LM carbs

[NicolCS at aol.com]

Someone suggested that...

<snip> Or, plug that venturi air bleed with JB Weld.    That will help a 
lot.  (with leanness)  The lack of a power enrichment circuit can be lived 
with, jet 
up a notch if you worry about too lean. <unsnip>

I doubt that plugging the venturi air bleed would have much if any effect on 
things.  The venturi air bleed affects only idle fuel and off-idle transition. 
 By plugging the jet, you would simply increase the % fuel in the idle and 
transition air/fuel emulsion.  To compensate and get back to a correct idle 
mixture, you would have to tighten the idle mixture screws and you would be right 
back where you started from.  (That's why smog carbs idle mix is about 3 turns 
out where non smog carbs are only 1 1/2 turns out).  

The writer's suggestion to "jet-up" if you are worried about leaness is right 
on the money.  

But who says the smog carburetor is "too lean"???  Who says engine 
temperature goes up when mixtures are on the lean end of the "normal" range???  I think 
both of these notions are nothing more than folklore.

 FVIW, I can't make either one of my EFI cars get hot (or even warm) and they 
are running mixtures FAR leaner than anything GM ever put into a Corvair.

The original GM testing showed about a 22 degree increase in CHT and Oil temp 
in a smog engine in comparison to a "regular" engine when operated in extreme 
conditions.  My personal theory is that this additional heat in a smog engine 
is due to burning fuel in the exhaust manifold (where it's all converted to 
heat, none to power) and reduced ignition advance in midrange RPMs (which also 
heats up the exhaust).

Craig N.