OK, I'm dumb, need help

If planning on coil over four link on a truck, then your into pro street categoriy anyway. Usually, some sort of stroker or hemi with a tunnel ram or blower is the norm just because of the general weight of trucks. If you want to go fast with a slant six in a truck, the ‘80-92 D100 or 150 ram becomes a better option with its lighter thinner gauge sheet metal. Up to 87 if you want to keep the stock frame, as they went to the 239 odd fire six (318 less two cylinders). Go with manual steering, the factory truck/van box is fine. Saves a lot of weight over the great iron anchor power box, frees up power for the driveline, too. Dodge Dakota plastic tank aluminum radiator or the like for more weight reduction. Replace the side and back glass with Lexan. If I was going to run coilover rears, I would replace the frame from the forward cab mounts back on the frame with rectangular chromoly tubing to the forward bed mounts, and then go to round chromoly tubing on back. Even if taking NHRA specs and increasing gauge and tube size by a “streetable safety” factor of 50%, the weight reduction would still be worth it. Want to get even more weight off of “old porky”? Check out U.S. Body source. Fiberglass body components in any form and rating imaginable...