good luck with whatever you decide gearhead,just so you know,I have a sollid roller 434,GM 4bolt block,deck plugs & cement.Run it on street like crazy,cleans up around town,never had a problem.Still I have to say,these are some of the smartest guys I have ever come across,& if I did it again,aftermarket block for sure.I did ALLOT of grinding & clearencing on pan rails.I also ran a .900 base circle cam,but it was only because I allready ordered it.when i received the kit from Eagle it all fit so well I could have got away with stock size.Still that is allot of gold in there,so,first teardown Dart block for sure.In the meantime,I still pound it with confidence.Would I spray it??Not a chance with GM block. already in 600-650hp range,as high as I would safely go.