You also have to remember that Tower or their parent corp bought out Thunder Tiger. The are going to mess with it till they ruin it. I think Bill has the correct idea of getting Dub Jett to make a 424 engine. He probably has been avoiding having a large production run as he seems to like to custom build all of his motors.
Anyway, back to Tower, remember when they first took over Thunder Tiger and they tried to jack the price way up. Customers had a major write in and they lowered it. So, I guess to cut cost they have gone to ABN motors now which will wear out quicker that the ABC motors.
I could be wrong but as big as Tower is it is all about the money.