intake manifold

[351wStang]

600 cfm is gonna be too much for your motor as stock as it is. If you spin the motor as high as 5500 rpms then you will need something around 550cfm. Although I doubt you want to spin a stock motor with a 3.5" stroke and nearly 6" rods (5.955" actually) up to 5500rpms. If you spin it to say 4500rpms you will need something around 450cfm. I would suggest a Performer series 500cfm carb.
Those cfm numbers are just quick math and dont always hold true, but they are close. One of the biggest problems with modified carb'd engines is people thinking the bigger the carb the better. You may be fouling plugs left and right with that 600 up there. If driveability is your main concern I would not suggest a 600cfm carb.
I'm building a wicked 351 right now and only going with a 750cfm Demon.

[fordforlife]

that would explain my black plugs (after about 3 days) and prob my smoke, lol. do you have any idea on the jet size i would need? thx for all your help!!!!

[fordforlife]

by the way, yes drivability is my main concern. yes i'll be offroading, but i want to be able to drive it around town and stuff too.

[fordforlife]

also, 351wstang, is that a 71 or 73 mustang, or am i way off?

[351wStang]

Way off. Its a '65. Just has a Boss 429 scoop on it so it will throw you off a little. No I'm not sure about your jet size, you shouldnt have to change anything if you get the Edelbrock carb I was talking about. Good luck.

[fordforlife]

alright, i do appreciate it!!! i like the car too!