Cut the wheel wells. The truck just looks better that way. Once that's done, there's no clearance problems with 31" tires. A common myth is the so called need for a body lift. Just do what Ford would have done, if they took their heads out of their a..... and made the 351 an option. The '69 Mustang 351w 4bbl only needs a modified Bronco 289-302 oil pan, to be a direct swap. Crown Vic 351W pans from the '80s are a cheap substitute. The EB air cleaner works better than any after market type, and the stock '69 4 bbl intake works perfectly. All the problems are the result of installing higher intakes and trying later 351 pulley systems. The '69-'70 Mustang 351W includes all the adapters needed for the swap. These are now cloned by EB vendors. The harmonic damper, fly wheel, and torque converter on EB 289-302s work with any 351W.