I have a 1995 350 mag(carb) motor low hours. I need info on how much gains come with a 650 carb and air gap edelbrock manifold. Does the intake need to be a marine one or can a auto work. Is there any gains in removing the water pump and going to a cross over. any help would be appreciated.

Most likely you won't see any noticable gain in speed or horseower by just putting a different intake and carb without the other corresponding parts needed to make speed and horsepower. Invest in a good exhaust system first ,you can't put more air in if it can't get out.Most exhaust systems are expensive but well worth it in the long run.Once you get the exhaust squared away then go for a little more cam and an intake and just rejet your carb if your on a budget.