Actually, these should be more durable than a tubular manifold, especially if the tubular was welded or constucted poorly. Some of the best manifolds I have seen were from Full-race and Hytech. Top notch construction and some of the best welds in the business, hands down. Do you plan on keeping AC? What kind of radiator do you have-half or full. These may force you to go in one direction or another. Cast manifolds are cheaper, more durable, and most will allow the use of AC, PS and a full size radiator. The Full-race will make more power, better spool, but some wont work with ac or larger radiators, and cost quite a bit more. Talk to Terry(Boostfed). He'll hook you up. Awsome prices.