OK I have A 77 camaro with new engine and transmission. the problem i am haveing is with the 625 demon Jr carb. the engine is a 355 cid with about 410 Hp. the car runs fine just driveing it but at WOT at about 75MPH and 3500 rpm it will lean all the way out. changeing jets and uping the fuel level will not help. on yop of that i am only geting like 2.5 MPg. I am thinking about puting a Edelbrock 750 on it. can i get some feed back on what would go good with this.

someone help this is driveing me up the wall

 

i think it would be a smarter choice to buy a new carb. demon carbs are one of the best out there, but a 625 jr carb is really restricting that motor, especially having 410 horsepower. the reason why it leans out at high rpm is because that small carb cannot supply fuel fast enough. a stock 350 is supposed to have no less then 600cfm, but yours is not near stock. if you are going for a streetable, easy smooth driving engine, then get an edelbrock thunder series 650, because the performer series does not make 650's. a 750 would run on your motor, but unless tuned absolutely perfect, it can stumble when u stomp on it. if you are looking for a more raceable car that u can sacrafice a smooth idle and such, then a barry grant 650, preferably the speed demon. i only hear good from them.