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
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