need some help.... carb tuning question

[evobuilder]

so I just swapped a Holley 750 for a Eddlebrock 600 (it was wayyy over carb'ed).... to my 65 GMC with a mild 305. When I put the air cleaner on.... it runs like crap, but only after some driving (like it is cutting out of fuel).
Also... when I plug in the electric choke.... it won't even start. Runs better without it.
Any thoughts? and before you send the link to Eddelbrocks site, I already know it and have been through it extensively.
Thanks!

[markeb01]

It could be several things. The primary jets may be too large causing the engine to run rich, and when the air cleaner goes on it reduces air flow - causing it to run so rich it chokes on fuel. The same problem would apply to the choke if it's already running too rich. The choke may also be set too rich for the temperature. It may require leaning out the setting a bit by rotating the thermostat housing so it doesn't close the choke plate so far, under the current weather conditions.

These carbs are easy to tune, but require a strip kit that includes different rods/needles and jets. If you shop for a strip kit, the old Carter kits had a lot more parts in them than the current Edelbrock offering, if you can find one. Here’s a current listing on eBay:

http://cgi.ebay.com/ebaymotors/Carte...Q5fAccessories

http://www.summitracing.com/parts/EDL-1487/?rtype=10

The rods can easily be changed without removing the carb. Just loosen the screws that retain the caps (do not remove the screws). The covers over the rods & springs can be swiveled out of the way, minimizing the risk of dropping one of the small screws.

Also, if the Holley has been running rich for a while, the plugs are probably fouled and may require replacement before you get good performance. You might also want to check the timing to make sure you have enough initial advance dialed in. Other things to check would be to make sure you have no vacuum leaks, and that the hose to the vacuum advance is connected to the ported outlet.