[Rich Biebel]

OEM blocks vary a huge amount in hardness as well as wall thickness.

OEM blocks are often way offset from center on the cam and crank as they relate to the cylinders and other issues as well.

OEM blocks often have a lot of core shift......cylinders are thin on one side.


With the power levels being what they are even in stock engines and also the cost of the parts to build a good engine.....any OEM block considered for use should be hardness tested and sonic'ed for wall thickness....

We did this in the shop I worked at 30+ years ago.....and a soft block or a thin block was just not used....

I would not hesitate to fill the block no matter what.....but as was stated filling a block that is already machined and at size is not the right way to go....it should be done before the block was finished....

My last 350-255 was a stock 010 block at .040 over...filled block.....ran 11.80's in G/SA with TRW pistons....stock rings.....untouched heads other than old school legal VJ and CC prep and untouched intake.....old Lunati cam with std type lifters....that was 1996 and it was a good 4-5 tenths slower than the fastest cars....

I shifted that 350 at 6600-6800 and it was a powerglide trans. 3 speeds were not legal back then..

MPH was never better than 112....usually less