Why are people scared of big blocks.

[Ziegelsteinfaust]

A friend i did a side job with. Told me a friend he has got a older RV that he, and his wife plan to restify. Not sure what it meant, but probably keeping the 70's charm on the outside. Then polish up the interior.

The 454 runs fine according to the story, but he wants to get rid of it for better mpg. By installing a 350 that will have a few nice things. I get it if a Cummins was installed better mpg would be assured.

The RV is a huge Winnebago box. It is litterly square. There will be no mpg to speak of. With the big block it will get 8-12 depending on terrain, and no small block will do better. The load is to great on the engine at just highway speed, and it is a lot to overcome.

Personally I would do the bolt-ons to the 454, and tune it. Or maybe add efi of some kind to get it started to better reliability. Then if I like the RV a lot I would add a 4L80E, and rear end regear to match the combo.

Are my friend, and I right he is crazy to replace a running 454 with a 350 in a RV?