Would gt40 valves fit in a 289/260 head? and if so how do i go about doing this? Iam thinking of doing some 289 heads on my 306 and i would like a little bigger valve ,but not the 1.6 exh valves. I hear people doing this mod alot and i would like to know what cutting is done to the head?

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83\' capri 306 carbed FMS E303,Tfs springs, RPMintake BBK headers flowmasters C5/c4 373 gears SSM uppers CE3way dragshocks,summit ignition drag car in the making..