I found that all of the rubber air control and intake manifold hoses (and there are a LOT of them) were hard to the point of not sealing on the '78 450 engine - replacing all of them ($$) made a major difference in how the engine runs (as it wouldn't even start before). I agree with Trampas that the 560 is the V-8 engine to have. More power and better mileage.
On 3/30/07, Trampas <[EMAIL PROTECTED]> wrote:
Personally I prefer the latter 560 and 420 engines after they changed the injection system. The biggest problem I have found with the 117 engines is the mechanics. The engines are great going well over 300k miles with no oil consumption. However a jack leg mechanic can very mess one up in a heart beat. My 420 had all kinds of valve train problems mainly because a mechanic stripped out the cam tower bolts, then heil-coiled them but left shavings in the holes. Thus when torqued the cam towers did not seat. The main problems with the engines is the fuel injection system. They do not like to sit for long periods. If they do they will gum up and not run right. Other than that you change oil and timing chains. Trampas
-- OK Don, KD5NRO Norman, OK "Even if you're on the right track, you'll get run over if you just sit there." Will Rogers '90 300D, '87 300SDL, '81 240D, '78 450SLC, '97 Ply Grand Voyager
