Even shorties can offer advantages over the manifolds....even edelbrocks....The idea behind the shorties is to meat emissions compliance, get a CARB # and still offer a performance advantage. They do flow better than stock manifolds...not much but still... So upgrading on a pure street car is still worth while. I helped a buddy get his 95 Formy to an uncorrected 13.5 NA with shorties, catback, cutout, 3.73, 2800 stall, and pullies. Still had the TB coolant hooked up and egr on it. Car was 100% emissions legal. Then we added a 150 shot and the car ran 12.3-12.5 all day long on drag radials and still cut 1.77 60' times. So there are a bunch of little things that add up that will help. Now yes LT's would have been the way to go, but he bought the car with shorties and we left it....I so wish I had finished his build....101mm fed 355....Oh that was going to be fun...