Dan,
What is the most a person can expect out of a Gen 4 block power wise?
I have heard they are weaker than a Gen 3 block and the most I have seen a Gen 3 turbo car make with a top of the line (PROLINE) engine build is around 1600 HP.
What is it that makes the Gen 4 block weaker?
Hello,
Your question is a tad loaded; you can extract as much power from a Gen-4 engine as any other Viper engine [and then some], provided it is built correctly. For example, a high-revving re-studded, de-stroked, heavy-wall, billet crank, dry sumped Gen-4 should have no problem getting up into the 2000+ range if you really wanted to build such an engine. As pointed out above, the Gen-3's also have no problem getting into this range on a good build.
The issue of Gen-4 "weakness" is not an issue of structural problems- quite the contrary, they have thicker sleeves, stronger caps and bulkheads, thicker deck and far superior cooling layout even compared to Gen-3. The issue of "weakness" stems from supplied hardware size and types, and the rod/piston combination they have. The hardware is the primary issue on larger builds, as the Gen-4's use substantially smaller hardware than any other generation. These should be changed out to a larger size when building a Gen-4 engine. There are different ways of accomplishing this, it all depends what investments a given builder has made towards the problem. We have oversize custom studs made for us specifically for this issue. There is however a side advantage: due to the sizes used from the factory, it requires a jump to a 9/16" stud on the Mains at a minimum [though we do main & head in 9/16", some do 1/2" on the heads], which results in a stronger bottom end than even the studded Gen-1/2/3 cars from a hardware standpoint. The Gen-2/3 cars would be sketchy at best trying to use a 9/16", as they are too close in size OEM [1/2"] and the threads would not be complete- and a jump to 5/8 would very likely not fit in the application at all without major clearancing all over the place [and may be at risk for punch-through on some oddball castings], as the 9/16" hardware is a tight fit already.
The pistons have also proven to be a bit more sensitive to damage than the Gen-1/2/3 engines, but on larger builds, this is of course a non-issue.
In short, the Gen-4 engines require additional money to be spent to build them correctly, but they also have the most to offer when built right.
