[Martin Walker (Tyrefryer)]

Does anybody know where I can find performance curve diagrams for Chrysler engines as they left the factory?

In particular I'm interested in the 4 barrel 340ci horsepower and torque curves in standard setup.

[Dave-R (Roppa440)]

I have never seen any. In fact I'm sure Chrysler would have kept the real power curves for most of their engines 'under their hat' anyway.

Having said that I have a factory diagram explaining the 1960 ram intake and it has a torque curve chart showing the difference between a 1959 and 1960 D500 engine.

I also have a baseline power curve for a 1986 "police" 318 engine with swirl port heads and 8:1 compression. It peaked with 180hp at 4000rpm and dropped off rapidly.

[Dave-R (Roppa440)]

If you just want to know the peak torque and power that info is in quite a few books like the chiltons manual. Remember they measured power different from 1972.

So in 1971 the 340 4-bbl put out 275hp @ 5000rpm and 340ft/lbs @ 3200.

In 1972 the net figures show 240hp @ 4800 and 290lbs @ 3600.

That is not the whole story though because compression was dropping year by year as well so in 1970-71 it was around 10.5:1 compression and in 1972 was 8.5:1.

Then they also had to please the insurance companies. People were not going to buy cars that cost a lot to insure so it is thought some models were rated at something other than peak on the power curve.

[Martin Walker (Tyrefryer)]

Thanks Dave, those figures will do me for now. Cheers.