tazdevil

i am about to rebuild a 2005 mercruiser 6.2 the block cracked because of bad winterization .i found a 5.7 1998 block what do i have to modify to the block to install the complete rotating assembly in the 5.7 block ? second question can i stroke this 6.2 (377) too 383 and keep all of my mpi setup and ecm without any ecm reprogramming

Mr Maine

They blocks are basically the same. You may need to clearance the 5.7 block for the longer stroke.

The 377 is already stroked. To get a 383 you bore it over .030. You shouldn't have to change anything on the ecm with such a small change.

CC230

Taz,
I just built a nice little 383, I got a nice low mileage '96 roller block and didn't have to clearance anything. ( I did just to feel better while I was deburring it) And as Mr Maine said a 383 is a .030 over 377.

Trash

I will concur with the above. NO tune required. Any late model 1pc rear main seal block will work. Clearance of rod bolts in block depends on the core shift of each individual block. It is likely you would need none to minimal clearance work. You can also buy new GM blocks pre-clearanced for stroker combos.

airjunky

iTrader: (2)

Personally would try to leave it at 377 if clearances check out .(it should be oddly tight ) vortec blocks are good at what they do but skimpy on the meat compared to the prev gen and can be really skimpy compared to the back in the day 2 piece seal 350 hign nickel with a 400 crank. Or one of the lt1 sleeper strokers

airjunky

iTrader: (2)

Plus it will all jive balance wise as is .