Two bolt or four bolt, it really only matters if you are going for a full tilt Hipo build or plan on putting a blower on top. The "smog hog" motors do just fine with a good cam, cleaned up heads, good intake, right carburation, and 8.5:1 flat top pistons. More than enough there to put you back into the cushions when the foot goes down and still give decent mileage with the right rear gear. Don't walk away just because of the 2 bolt mains.
Here is the link to look your suffix code "CMJ"
http://www.nastyz28.com/sbchevy/spcode2.html
