I have a 4" Cervini's on mine to clear my Holley with 1.25" spacer that barely clears my monster Sheet Metal valve covers, my friends kid me about it looking like a Big Block. Remember it isn't the intake that is the issues a lot of the time, it is the intake tube, this is where you need to be careful. My C&L 76mm tube clears the side of the rasied cowl by about 1/2" the intake has another 1.25" or so before it will hit the hood. My vote is for the 4", never know what the future holds.
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Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension, SPEC stage III clutch, Lakewood SFI bell, S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon! <B