Probably not exactly what you're looking for, but the F*rd Windstar e-fan conversion is a great way to free up some horsepower. mostly on the top end. Vortec heads as well. The Blazer gas tank mod is a great one, too. MSD has a nice digital ignition module with a built-in rev limiter, that is one of my favorites. No more floating valves or bent pushrods. Another is swapping the front output shaft of the NP205 for a F*rd front output shaft. It is 32 spline, just like the rear output, giving you a wider option for larger, stronger yokes, all the way up to 1410. Another neat one I've heard of but not tried yet is a 2005-ish D*dge 2500 front driveshaft. It is a flange-style double cardan joint just like ours, but with 1350 u-joints throughout, allowing a higher running angle and much stronger than 3R joints ours uses. It will have to be cut down to fit our trucks but it is always cheaper to have a driveline shop cut a shaft down than lengthen one. Converting to rear disk brakes is another good mod. You can use Cadillac Eldorado calipers if you want to retain your park brake but I don't remember which year works. The rear shackle flip is another one I like, easy way to gain 4 inches of lift without using lift blocks, and much cheaper than lift springs.