181 cid exhaust manifold interchangeable

I'm trying to find out som

I'm trying to find out some info on my 3.0/181 cid motor. I just had the long block rebuilt and ordered a new exhaust manifold for it. the original manifold had a 6 bolt mounting pattern and the one I recieved has a 5-bolt pattern. we cross referenced the casting # and the one I recieved is supposed to be the right one. I'm concerned about the difference in mounting bolts but I was told by a "40 years in the business" mechanic that I should install it and forget about the one bolt difference. If anyone has any expierence with this I would appreciate some additional input on this subject. thank-you!

FYI! I just found out from the

FYI! I just found out from the manufacturer of the manifold that the 5 bolt pattern will work to replace the old 6-bolt pattern exhaust manifold on my 181 4 cyl. they informed me that that is how they are manufacturing now and to not worry it won't leak due to the one less bolt area not having torque pressure. my motor was a 1974 model and the available manifolds that have a 6 bolt pattern are slighty different and are manufactured for a mid 1980's 3.0l GM.

"glad we could help, Mike!"

"glad we could help, Mike!"

"Pretty good when someone answ

"Pretty good when someone answers their own question...

FYI this is the manifold Mike is refering to 18-1955-1"