Is there a difference in a Viper racing block vs. Stock Viper block?

[Qualitywires.com]

I noticed that the Mopar Performance Viper block was around...is there a difference?

 

[Joel]

Yes, as far as I know, the GTSR block uses a different crank with smaller(?) main journals......the block is machined differently in this area. Dan Cragin would know, I think it was he who told me.

 

[jp]

As told, the mains are narrower, about .25". The GTS/R crank is modified for the external oil pump. It does also have slighly thicker liners (three different liners produced though)
Most of the block out on the market today were refused by the Race engine builders. They were out of specs and needed to much work to be usable as a endurance engines.

 

[acrdakota]

I believe the R block also has 6 bolt cross bolted main caps and as stated is setup for a dry sump oiling system.