Craig; what is the engine compression you know 8 to1 or not? I don't want to depress you but these 79 302's with 8 to 1 were only about 130 H.P. with a 2 barrel carb. Now your a little more with the intake and 4V carb an cam/headers all this helps.But you've got a heavy truck and with out more horse power it will probable will bog down a little, I would have told you to get some early 289H.P. heads for more compression of 10 to1 with about 230H.P. plus what you've added probable 280hp.But you've just done your heads. We had the same problem with the one that I worked on too. It would bog down under a heavy load, those trucks are very heavy for that 302 especialy if it has low compression of 8 to 1.


Vegas