I've having trouble with my 66. Every time I start it, it takes at least 10 minutes of me appling gas to warm it up. We've tried as hard as we can to tune it right but we believe it may be a choke problem. I'd like to replace the choke and at the same time replace my stock 2 barrel carb with something higher end. I'd like to change to a 4 barrel but I'm not sure if I'd have to get a new intake manafold at the same time. Please give me some suggestions as to anything that might be wrong and also what you suggest for a new carb. Also I've been getting really bad gas mileage, around 12-15 per gallon is there anything I can do to help this?