: 500 - production power decrease and engine changes?

09-04-10, 06:51 AM
During the production time of the 500 engines their power has been significantly decreased due to emission control requirements.

Does anynody know what exactly has been changed, year after year??
(heads, cam, introduction of EGR, carb set-up,.....?)

09-05-10, 11:37 PM
The lowering of the compression ratio was the main reason for the lowering of power output. But if you are looking at the book numbers they changed the way they calculated them in the early 70's.....68-69 had the highest ratio and 1970 was just a little lower.. then in 71 to 76 had the lowest ratio.. changes in the block in 1970 were made for better oiling...small chamber heads were made until 1973 were better than the larger chamber heads that were made 74-76....pistons must be matched for the heads you use....

09-10-10, 10:44 AM
Often the cam timing was changed by changing the timing gears. Do some research, if so a pre emissions timing set will give more power.