261 Truck Engine

[Grant Bowker]

I suspect that the same block might have been used for both car and truck versions depending on where holes were drilled to permit or block access to oil galleries etc.

In the US, people tend to think of the 261 as a truck engine while the same trucks in Canada often got the 235. The 261 in the Pontiac seems to have been used rather than a V8 in the low end of the spectrum in models that might have gotten the V8 in the US.