carter afb tuning

[73-charger-383]

I've got an old weber/carter afb carb that I rebuilt to throw on my charger, but i'm having issues tuning it.  It's a 750 cfm carb (pretty much a edelbrock 1407).  At idle/part throttle it runs fine - but when I got to wide open throttle it will bog to the point that I could kill the engine if I held it.  - I know that 750 is probably too big for my engine (it basically a stock 383 from a 68 newport) which I swapped out the 2 barrel for this four - and put on headers/dual exhaust.  - I'm swapping cams/switching heads soon, so i figured i'd use the 750 at that point.  For now I just want to be able to burn around town some with that carb.
  So -- it's not backfiring or anything when it goes WOT, so i'm assuming that i'm just dumping too much fuel and it's bogging down.  Are my issues more related to the springs being too stiff, or do it need to swap out the secondary jets? 

[RallyeMike]

I might suggest that you read the plugs before assuming it's too much gas. It could also be too little, which could point to an issue outside the carb.

[BSB67]

I might suggest that you read the plugs before assuming it's too much gas. It could also be too little, which could point to an issue outside the carb.

This.  And, I suspect there is something wrong in your rebuild.

[73-charger-383]

Well, I'm basically a three year old. Dissatisfied with the possibility that I could have screwed up the rebuild, I decided to do the cam swap and switch heads today. So in goes the comp cams 268h and the 915s. - but for the record the plugs were pretty black.....