Valve Springs & Roller Rockers

[StreetStang37]

Which valve springs and roller rockers should I get? Will 1.72 roller rockers fit under stock valve covers? Is there 1.7's that will fit? I won't be getting a cam or heads or intake so the valve lift won't be a question, atleast not anytime soon. My valve springs are probably tired because I feel a drop off at the higher rpm's, and I am getting a new fuel pump since this one whines so much now (I know, that may be my problem). Also, how difficult are they to install and how much would it probably cost if I took it somewhere? I know valve springs are like $75 and rockers are $250 or so. I will be adding a supercharger eventually, there are just other mods to come first.

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1993 Mustang GT - March Ram Air & Pullies, K&N, C&L 73mm MAF, Super Competition Hooker Headers, 2 1/2 in. mandrel bent cat back, High Flow H-Pipe, Pro 5.0 Shifter, 16* Timing Advance