Get a different computer or just put a perfomance chip in it, the situation is im goin for a 305 carbto a 350 carb, and i figured that a extra 45 horses will send the computer nuts!!

 

Shouldn't be too much problem at all for the carb. The fuel compensation in the carb is just for closed loop, and isn't a large factor in the whole scheme of the fueling. May need to tune the needles and hangers, and vacuum/air door opening rate, for full throttle power, though. Can use a wideband to tune those, or do it the old fashioned way.

The spark advance in the LG4 is pathetic. The chip is what controls that, though. Can probably get away with just adding base timing, by moving the distributor a little. I think the base setting is either 0 or 6 for a stock setup. Bump it up about 4-6 degrees, and see how it does. If you have a scan tool, you can see how much knock it has during full throttle.

Not many people have found a much for programming the chip on these ECU's. There is a way, but not many people here do it. I've never tried it (though I looked into it a while ago).

 

If it's a feed-back carb, this is the one time I would actually support ditching the electronics, and going to a fully mechanical carb. The feed-back carbs never seemed to work quite right, and as mentioned there is very little information about tuning the bins used for these systems.