did GM ever produce a factory 400 smallblock with 4-bolt main caps? i have a bet with a buddy they don't exist.who's right? :confused:

they exists

3951509....400...70-71...4
3951511....400...70-73...4...Some replacement blocks had 2-bolt main caps
www.mortec.com (http://www.mortec.com)

if i remember correctly, the 2bolt is stronger

Tie,
I am afraid you lost the bet :( Plenty of 4 bolt 400's were made by GM. However, most engine builders consider the 4bolt 400 block to be weaker than the 2 bolt blocks. If you looked at one closely you would see why...the extra bolt holes weaken the main webs considerably.