When I put the Crane 2031 cam in, my pushrods ended up being too short. Crane sells a 6.375" pushrod, which I bought and added shims under the roller rockers to get the proper preload. They'll also make custom lengths for you. I've still got some valve train noise, had a friend who races his 347 stroker listen to it and said it's not unusual.
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86 GT, GT40P heads, Crane 2031, 1.7 RR's, Cobra intake, 65mm TB, 73mm Vortech, 24# injectors, MAC GT40P headers, 2-1/2" BBK H-pipe (w/cats), Flowmasters, 3.55s, Groundpounder subs and lower control arms, 277 RWHP.
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