Kevin, Federal law required that all 1971 passenger car engines (except special high performance versions) be able to run on regular grade, low-lead fuel. That meant that compression ratios dropped on almost every engine. On Imperials, the 9.7:1 CR of 1970 became 8.8:1 for 1971. Compression ratio and power output are directly related, so the 350 hp (gross) of 1970 dropped to 335 hp (gross) for 1971. Net horsepower was also advertised for 1971. This is the more realistic value of power output that results when fan losses, alternator losses, coolant pump losses, air cleaner installed, exhaust system installed, etc. are taken into consideration. The 71 Imperial 440 was rated at 220 hp (net) for 1971. So, directly from the 1971 Chrysler dealer specification album: Standard V-8 for 300, New Yorker, and Imperial: Horsepower @ RPM........335 (220) @ 4400 (4000) Torque, lb-ft @ RPM.........460 (350) @ 3200 Displacement, cu.in..........440 Carburetor..........................4 barrel Compression ratio............8.8 to 1 Bore and stroke.................4.32" x 3.75" Air cleaner..........................Single snorkel Camshaft............................Special Exhaust system..................Single, low restriction Fuel recommended...........Regular I have a 71 Imperial Owners Manual and I don't see 375 hp anywhere in it. On page 59 "Engine Specifications" I see that the compression ratio is INCORRECTLY given as 9.7:1 but that may have been corrected in later printings of the manual. Note that "Fuel" is listed as "regular" which contradicts the 9.7:1 value. Are you looking a the fuel usage statement on the back of page 59? If so, you need to read the WHOLE page carefully. You have a regular fuel engine in your car, taking 91 octane "low lead" fuel. "Such fuels are suitable for use in all 1971 Chrysler Corporation passenger cars EXCEPT THOSE CARS EQUIPPED WITH ENGINES DESIGNED SPECIFICALLY TO OPERATE ON PREMIUM FUEL." One of those engines is listed as the 440 cid high performance version, single 4 barrel carburetor, 9.7:1 compression ratio, 370 hp. This is the TNT 440 with dual snorkel air cleaner, high lift cam, and dual exhausts but it was not available in an Imperial. Pete in PA 70 LeBaron From: "Kevin Pacheco" <kevin50187@xxxxxxxxxxx> Subject: IML: 1971 440 335 or 375?!? Date: Thu, 11 Apr 2002 18:53:41 -0600 Reply-To: mailing-list@xxxxxxxxxxxxxxxx I want to know why my owners manuel says that my engin has 375 horse power, and all the shop manuels say its 375 too, but every one here says its 335. Im going with my owners manuel, what i want to know is where did you get 335 horses from? Kevin Pacheco 1971 Imperial