Very interesting as I have a 253 in my 37 Dodge pick up and have been toying with the idea of a driveline upgrade, have a clean 308 black motor sitting in shed and also have at my disposal a pair of 5.0 EFI heads, new set of headers and quality manifold, and also a fresh pair of L34 heads recently recod, transmission is currently a 5 speed supra, the 253 is fine just running single exhaust of extractors and 2 barrel carbie, some people have said to me if its not broken dont fix it and others have suggested anything from a 350 chev to a Windsor 302, I agree 253 dont usually arouse the most enthusiasm but this is my 3rd vehicle owned with one and I cant really fault them I was told recently cant remember where that they have more torque than a 308.