I recently picked up a 1984 Z28 for my kid that someone installed a 350TBI motor from a late 80's truck. We are not going put a whole lot of money into it as it runs real good and I just assume leave it alone but I know the manifolds on these motors are a huge bottle neck and one of them has a crack in it. I can get a set of headers for the price on one manifold.

I am going to install some shorty headers from summit the first ones have a Collector diameter of 2.5 inches and 1 1/2 inch primaries the second set I am looking at and will require Y pipe modification has a 3" collector and 1 5/8 inch primaries.

Which of the two would work best for this motor? Would there be any gains using the first set or should I use the second set? I kinda want to use the first set because it has the ball flange and is a direct bolt in with no Y pipe modifications. However if there is much more to be had as far as performance and MPG I will use the second set...remember this is a totally stock motor with no upgrades planned in the future.

 

just use the first set. You will not see/feel any gains going with the larger tubes. May even hurt some.