Rear end question

[Vishnoff]

I am drawign ever so nearer to doing my brake conversion. But I have one question, and i am hoping that maybe one of you guys can help me. SeeI plan to do a disc brake conversion and also change my 4 lug spindles over to five lug spindles. The current rear end in my car is the 7 1/4 inch rear end. Later i plan to performance out the lowly inline six, that sits under the hood. Will my current rear end handle 250 to 35o horsepower or should i just replace it with an 8 or 9 inch rear end?



------------------------------------------------------------------------------------1967 Mustang
rebuilt inline six, 200
awaiting brake conversion, and new rims...