Shane, the only clearance I've done is trimming the firewall just above the trans opening, not so much that I can't use the original trans cover though.
This was more to do with getting my pinion angles right rather than engine clearance.
The only other issues I'm having is the trans dipstick is tight(easy fix) and fan clearance which i'm dealing with at the moment.
The short water pump certainly helps.


1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.