Can only state that I have had no problems with my 56 Plymouth Sport Suburban 277ci V8 with factory power pac and overdrive. Full rebuild 6 yrs ago including new pistons and 60 over bore, now having an effective ratio of (only) 9:1. Have put perhaps 10k miles on it, many highway, and it cruises 75 no problem. It has been from Ok City to Barrie Canada. Have not experienced any trubbles with gasoline or preignition or whatever. And expect it to run another 20 years unless fuels get super exotic- I see either Ford or Chev has a variable fuel engine as standard now, that runs on the 85% ethenol fuel. (anyone know where its available and whats the cost?). I dont know of a finned mopar that has over 10.5:1 and thats a special case. Normal fuels (not oxygenated) should cause us no problems also since Chryco has had hardened exhaust valve inserts since year one. Thanks Chrysler! L. |