okay well to make a 302 truck to a 351 truck you need to change the following, you need a computer and wiring harness (motor/injection) from a 351 truck, you need exhaust from a 351 truck, ( y pipe) because 351's are wider on top, you need to use a 351 flywheel because the 302's have a larger weight and the vibration will be terrible and tear the bottom end apart ( i know from experience ) the fan shroud on a 351 truck has a different offset that a 302 truck has so the fan will not line up with a 302 shroud, you need the 351 trucks shroud, on a 351 mkotor there is not nock sensor like a 302 has, this is the sensor on the top rear od the motor going straight down into the block just behind the lower intake, so you will not need to worry about that ( just fyi in case you noticed) and the EGR is located in the same spot on the upper intake but a 302 EGR system runs into the lower intake, as where on a 351 truck is runs into the passanger exhaust ,manifold, so get the exhaust manifold from a 351 truck unless your fabbing something yourself and using headers, and since the motor is wider things will be more stretched out, when i did this same swap my ac lines were a little stressed to bolt up so i removed a mount from the firewall to loosen it up a bit and it worked fine. I think i basically coverd everything here but i would advise to leave it a 302 or 306 truck because with all the money your going to spend you could build a 302 with more power than a stock 35. I spent 1200 dollars on a crate 302 from S&S engines and have a few minor things done to it and it has more power than my 351 ever did, just my opinion tho, good luck