The Stovebolt Site Forums The Shop Area Engine Shop how to ID GMCs engines?

My friend has a 57 GMC USA built truck
It looks like a 235 annd he thinks it is a 235 since Canadian built GMCs have Chevy engines.
I thought it was probabley a 270.The valve cover is scripted GMC and the rad is different.
Do 270 look the same?
Do they take the same points?

thanks