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440

Started by rooroo, August 10, 2009, 07:27:48 PM

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rooroo

Got a question for the gearheads. I am looking at a charger r/t with a 1973 440 in it. Obviously the numbers do not match but wondering what steps were involved in retarding the power these engines made as opposed to pre 72. I would like to have it run as a real 440 should. I am thinking it is the internal timing gear and/or a different carburetor. I want to be able to restore the lost power without needing to tear the whole engine apart. I know part of the reduction was a switch of the measurement standards but I also know the engines were also physically reduced in their horses. Thanks!

RD

well.. a new cam, carb, intake will help.. but the 440's compression is your greatest enemy.
67 Plymouth Barracuda, 69 Plymouth Barracuda, 73 Charger SE, 75 D100, 80 Sno-Commander

RD

i shall expand on this.. the standard compression ratio of a 1973 440 could range from a lowly 7.8 to 8.2 to 1.  the differences between HP engines and standard engines were camshaft, valvesprings, intake and carb (in most cases).  The 69 440 had a standard compression ratio of 9.5 to 1 and a six barrel 440 was 10.3 to 1.

to overcome the current compression ratio you will require to either:

1) swap out pistons
2) mill your heads
3) swap in aftermarket aluminum closed chambered heads
4) swap in 516 or 915 casting heads (closed chambered design)

you can utilize your low compression motor with a new intake, new cam, and carburetor, but you can only squeeze a orange so much before that low compression causes you to keep throwing money away in order to obtain performance of a higher compression engine.

NOW WITH THAT BEING SAID...

that is for a traditionally aspirated engine.  you can always throw a procharger on that setup and take advantage of that already low compression and allow the "boost" of the supercharger to increase your compression for you... granted, this is a very expensive upgrade, but it can be done.

before you do this, if you plan on it, it is good to know this:

1) supercharging increase cylinder pressures that cast pistons are not made for
2) your lower end (i.e. crankshaft and bearings WERE NOT made for a supercharger)
3) blowing an old unrebuilt engine can blow your engine.
67 Plymouth Barracuda, 69 Plymouth Barracuda, 73 Charger SE, 75 D100, 80 Sno-Commander