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1971 440 vs 1972

4404ME

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Hello All, I would greatly appreciate if a knowledgeable 440 engine Guru could fully explain/share ALL of the differences between the 71 440 vs the 72, when Chrysler de-tuned the 440 to comply with emissions standards, and EVERYTHING it would take in order to achieve the 71 power rating, and more, starting with most cost-effective gains. Or, I could ask to point me in the right direction - BUT - isn’t that why I’m HERE?!? Thanks!
 
Biggest deal would have been the compression drop from 10.1 to 8.2. The rest is the usual cam, timing,
tuning stuff....and of course, heads are where power is made.
 
Hello All, I would greatly appreciate if a knowledgeable 440 engine Guru could fully explain/share ALL of the differences between the 71 440 vs the 72, when Chrysler de-tuned the 440 to comply with emissions standards, and EVERYTHING it would take in order to achieve the 71 power rating, and more, starting with most cost-effective gains. Or, I could ask to point me in the right direction - BUT - isn’t that why I’m HERE?!? Thanks!

What are you looking to do:
1) Take your 72 engine and turn it into a 71 motor, or
2) Purchase aftermarket performance parts to achieve the 71 motor's power level?
 
A better idea for you is to clearly define what you want from the engine. Do you want stock appearance but with more power? Do you just want more power and don't care about appearance? Are you driving local/short distance or highway? What is your budget?
There are many mods that can be made that don't alter the appearance such as cam or pistons. Headers and rear gears change the response of the car.
What do you want out of it?
What kind of car are you working on?
 
The two biggest diferences were, drop in compression and net HP ratings. Everything else was basically the same.
 
The two biggest diferences were, drop in compression and net HP ratings. Everything else was basically the same.
Thanks Everyone, I know what I can do to achieve more power, but wanted to hear some feedback. So, thanks for that! What I am curious about is WHAT did Chrysler do, to lessen the compression, HOW did they do it, and things like that. Just curious I’ll post pictures as soon as I take some recent photos, and - bigger issue - as soon as I can figure out how to do that!
 
Biggest change was compression height of the pistons.... They went from about .080 in the hole (1.991 C/H) to about .160 in the hole (1.912 C/H)....
 
Biggest change was compression height of the pistons.... They went from about .080 in the hole (1.991 C/H) to about .160 in the hole (1.912 C/H)....
Thanks 1 Wild R/T, while I truly appreciate all of the replies, this was more along the lines of what I was hoping to learn. Any other details, please let me know! Just trying to satisfy my curiosity about the MY engine differences. SK - An original.. SAY IT!!! SAY IT!!!
 
There is not as much hp difference between 71 and 72 as it appears although the compression is a big change with the piston change in '72 like others posters described.. The reason the hp is significantly less is because all engines were rated at S.A.E. net in 1972 like r/t boy mentioned..This is with all the accessories such as water pump and what ever else that robbed power. I'd have to look at what all else is included. Compression in the rating changed from '70 9.7 to '71 9.5 according to there rating...but I doubt they even changed it..'72 8.2.. The '71 350hp was 8.8:1 that is probably even a little high they have a dish in the '70 piston. 73 is when emissions were worse on top of the lower compression.
 
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Biggest change was compression height of the pistons.... They went from about .080 in the hole (1.991 C/H) to about .160 in the hole (1.912 C/H)....
You know too much old mopar stuff. Or not enough not sure yet.
 
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