considering swapping my \6\ for a \8/

I am considering swapping out my \6\ with a \8/. I tbought the 273 would be a likely candidate for it since it is the smaller engine I believe and it would be going into my 63 Dart convertible.
I know the 318s are very plentiful but dont know size comparison to the 273 so if anyone can enlighten me on possible issues or caveats in cramming this into the restricted engine compartment of the 63 I would appreciate it.
Thanks a bunch in advance, and since this is just some mental masturbation on my part I would enjoy your thoughts.
cheers.
John
Author: admin