My LG4 are probably running too rich, because of various symtons. (I will also check if the ignition timing is retarded). But as I suspect my carb to make problems, I hope you can help me with tips/info. I contacted holley.com with pics pr mail and they wrote this: "The top of the choke tower hase been cut off with the List number stamped on it. I can not tell you exactly which carb it is. I can tell you it is a model 4010 which we stopped offering in '98. That carb was also originally a vacuum secondary carb and someone has rigged a mechanical secondary linkage up on it."(former owner) 1) Someone told me this was a cheap model/serie carb, and it had bad quality. Comments? Experience? History of this carb? 2) Converting a carb from vacuum to mechanical are described as taboo. See: www.bob2000.com/carb . Someone who has experienced this? Comments? 3) I probably have to buy a new carb (Edelbrock Performer 1405, 600cfm). Comments? Whats possible reasons would causes too rich mix on this type carb? Blown powervalves? Too high level in floats? Other things? 4) This Holley I have; in what different cfm was this model 4010 delivered?

No one that can help? No one knows............??

The carb series was offered also in a 750 model. If you go to the holley web site, you can look up the variations in the different versions as there's a master "list" # page showing all the stock specs ( jetting, power valve model etc.).
Yes, rich can be from a bad power valve. It can also be too rich from a previous owner being too happy with the jetting. There's also a possibility that if it were bounced around, the float level is now too high.
As far as junk, I've heard both bad and good stories. I've run the 750 version for a few years with no issues.

Given that it's been badly monkeyed with (no choke, vacuum secondary system removed, etc.) it's time to get a different carb. You can buy a good rebuildable core for a 600 vac sec Holley or 650 double pumper Holley at swap meets for next to nothing and then throw a $40 rebuild at it and have a much better carb than trying to rework that old dog. That is, if you're mechanically inclined towards rebuilding carbs.

Cheapest and easiest carb to purchase and rebuild yourself: Holley 650 double pumper. Double pumpers are simpler and easier for a novice to rebuild successfully. Vac sec Holleys are more complex and the vacuum secondary system is often confusing to a novice (which is probably why the previous owner of your current carb "rigged" it for mechanical secondary opening).

Thanks for answers everyone.

You mention swap-meet and used carbs to rebuild. But carb-cars (specially Am-cars) are seldom in Norway-Europe. Then used carbs are seldom to get. I havent rebild a carb before (its my first carb-car), and I think also I would prefer a carb type bolt on-and go (i.e. Edelbrock.....?)

I then have 3 choices from the same sales-company:
Edelbrock 600cfm-1405 (vac/man. choke):

1) I can order a brand new: Price= 420$

2) A Edelbrock-rebuilt one: 336$

3) The same Edelbrock carb, but rebuilt of Holley: 292$

I would prefer the cheapest but what do you think of these 3 choices? Are company-rebuilt carbs reliable? Holley are about same prices at equal. I will not use this car in winter, so choke-funktion aren`t important. If you want to read a better description of the prob, I have posted a tread at "Engine...."-tread. I have nothing catalytic converter or any else emission (and power) reducing equipment. The distributor was taken from a 350, and have both mecanically and vacuum-advance(no computer-control of ignition)