I have been splitting inline manifolds (not just chevy )for over 40 years and had no problems to date. In fact (in my opinion)the splitting the stock manifold has advantages. In addition to the mentioned heat riser useage and alignment problems, when the manifold is blocked, a hole can be added to the block plate to control the "rack"sound( some like it,some don't) and the harshness or tone of the system.I did a lot of these with a cracker box welder and Nickel rod and it helps to pre-heat the manifold
in a oven or simply placing it on a charcoal grille for a while.---Paul
