I have a 351w in my car and it fits nicely! What year is the pinto? The early Pintos had a smaller engine compartmeant (71-73) The 74 and up were made bigger for the 2.3 and the Mustang II's use of a 302. (the 74 and later Pintos were the same basic undercariage as the Mustang II) The 408 is just a stroker kit added to a 351w and will not change the size of the outside of the engine. My headers are Hooker super comp for a 302 that have been modified for the 351, two sets of pipes on each side go through the inner fenders and two go down beside the block. The egine will have to be set back a bit but it will fit. My buddy has a 351 in his '71 but he had to cut out the inner fenders, cut out the firewall (mostly because he used a C6 tranny...HUGE) and the tranny tunnel, moved the firewall back about 4 inches and made the trans tunel wider and higher. Jeff ps. when they say " long block"..... all they mean is that it includes the heads with the engine if the say "short block" it means just the block with no heads included.