Originally Posted by captainkf
I had considered that however I was concerned about how the mechanics of the rest of the engine would work. They are as follows:
-How would the propane conversion work? Would I need a new carburator or interface?
-Is the cooling system sufficient for a larger engine?
-Would the tranny bolt up?
-Can I use the same motor mounts?
-Would I need to replace any other components that make up the engine as a whole?
-How much power would I gain?
-How would this effect my fuel economy?
-If I go for the rebuild is it worth looking into some of the aftermarket components that are designed for "rotroding" such as camshafts, bored out pisons and different compression ratio's?
Thanks to any and all answers. -Richard
Propane carb & interface should work, though it may need to be adjusted (basic tune-up stuff).
Cooling SHOULD be enough...I've seen a 366 radiator cool a 335HP 502 in a box truck.
Since the 366, 427, & 454 are externally the same, the trans & motor mounts should bolt right up.
You MAY need a different flywheel/flexplate & harmonic damper for a 454...not sure.
A 427 would be worh an easy 50HP over a 366...a 454 75+HP increase.
Replacing a 366 with a 502 in a C-60 box truck actually INCREASED mileage ~1MPG, because the engine wasn't running WOT all the time anymore.
If you are keeping the engine propane-fueled, bump the compression (propane's octane rating is, IIRC, 106). DO NOT DO THIS IF THERE IS ANY CHANCE YOU WILL BURN GASOLINE IN THE BUS!
DEFINITELY get a better cam...call Crane or Comp Cams, tell them the vehicle details, & they'll tell you what you need.
Don't overbore more than ABSOLUTELY necessary....030" is good, .020" (if pistons are available) is better.
I would not even think about doing this without using:
Fortged pistons with chrome-moly or tool steel rings.
Stainless steel valves & hardened seats, intake & exhaust.
Maybe sodium-filled exhaust valves (not cheap)
ARP studs on the main bearings.
Double roller timing chain.