could be a bad head gasket or cracked head.
small block
a 400 small block Chevy has a 4.125" bore.
the firing order for a small block Chevy 350 is 18436572
The deck is the surface to which you bolt the cylinder heads to.
A cylinder is misfiring.
4.125"
160 foot lbs
65 FT. LBS.
65 ft lbs
If it is a V8 it is 65FT.- LBS.
The firing order is 1,8,4,3,6,5,7,2 with 1,3,5,7 on the left bank and 2,4,6,8 on the right bank. The distributor turns clockwise.
torque specs 350 Chevy heads65 lbs