The Stovebolt Site Forums The Shop Area Engine Shop 270 GMC Flywheel: 4 bolts or 6?

Hi All, I have just finished rebuilding my 270 for my '52 5-window LB 1/2, and a friend thinks I have the wrong crank & flywheel. Mine has 4 bolts, and no bolt to retain the balancer. He thinks all 270s had a 6-bolt setup. I see from the spec sheet that the 270 stroke is 5/16" longer than the 228/248, and my wedge top pistons did reach the top of the bore when I put them in. It looks to me like I have a 4-bolt 270 crank, and I hope I'm right! (and scared I'm not!) Any thoughts? Thanks, tom :confused:

My 270 was a 4 bolt, used the flywheel and bell housing from the 216 everything fit fine.

Tom

My 270 & all those I've worked on (WW2 models), have had 4x bolts.270's were made until 1962 and the later versions were higher powered - maybe some of these had 6 bolts.
The piston wedges do protrude up above the block.

Thanks guys, I'll put my wig back on...