C Murda

just wondering which engine BLOCK would be more reliable in high boost situations an LS1/C5R punched to 427 or a Dart Little M Race Block (as seen in summit racing) 400 punched to 427?

from what i know both the C5R and Dart Little M have siamesed cylinders but one is iron and the other of course aluminum. just from reading around it seems like all the LSx guys are all about using a C5R block for their projects and then i read up about how unreliable a 427 SBC is? is it just the OEM GM old 400's that were unreliable or are the aftermarket Dart or Motown blocks not good too?

ME Leigh

The stock LS1 block is good for 600+ hp. If it was me i would definetly good with a GenIII LSX style motor. They are far superior to all earlier SBC's. You could go with a cast iron Gen III LSX style motor as large as 454+cid if you really are going to be pumping in some boost.

C Murda

ya im plannin for boost. but what are the main differences when it comes to strength and longetivity between an LSx and Dart Little M aftermarket race block? besides the obvious aluminum/iron blocks.
to get more specific im liking the 427 more and more and i know that all the LS1 guys are raving about their C5R blocks but how strong is it compared to the Dart 400 Block that has 4 bolt splayed mains, siamesed cylinders (just like the C5R), and some other stuff that is like the C5R. to make it simpler, which is a better block to build for boost the C5R or the aftermarket Dart Race Little M block (400 mains)?..both would be 427

ME Leigh

I doesn't matter unless your going to make a consitent 600hp+ all day long, everyday.

It's really just a matter of what type of motor you want to build. Old school, or the much improved LSx motors.

If your really worried about breaking a block, which will never happen. Go with a iron LSx motor.

C Murda

im not too worried about breaking a block what im worried about is the thickness of the cylinder walls after a 4.125 bore wether it be in a LSx or Dart block.

ME Leigh

Well the dart block can be bored to 4.185" and still have plenty of material left. THe LSx motors use cylinder liners and are not considered serviceable parts. They have to be replaced during a rebuild.

I don't know what your worried about. Those blocks are designed to have a 4.125" bore.