GM LS engines have truly set a new standard for V8 performance and durability. However, there are  limitations  for  the  aftermarket  shopper  when  it  comes  to  finding  a  high  performance replacement for the factory block.

Aware of this dilemma, the research and development team at RHS® went to work designing and testing several different versions of GM LS engine blocks until they found the optimal solution for performance engine builders and racing enthusiasts.


The LS Race Block is designed for added clearance and mass customization. Available in both standard  (9.240”)  and  tall  (9.750”)  deck  heights  with  an  extra-thick  deck  surface  (.750”),  this RHS®  block  features  a  raised  cam  centerline  and  priority  main  oiling  via  an  oil  galley  that  is shifted outboard to allow rod clearance for a much larger stroke (4.600”) while also minimizing windage in the crankcase. Using computer-aided design, the cylinder walls are Siamese cast with press-in spun cast iron liners. Cylinder liners are available in both standard deck (5.67”/5.87” – same as the LS7) and tall deck (5.94”/6.38”) lengths. Also featured is a 6-bolt head design with a full water jacket around each cylinder (based on the LS7 design).


For  quality  control  assurance,  RHS®  performs  a CT  scan  on  each  block  (similar  to  a  medical CAT  scan)  to  maintain  maximum  casting  precision  and  consistency.  Combine  all  of  these features with a superior finish quality, thanks to the RHS® patented Clean Cast Technology™, ultra-precise computer aided design and extra surface material to allow custom machining, and you’ve got a GM block that sets a new benchmark for LS horsepower, torque and durability.