New to me P337 - Is this a problem?

[Rule303]

Hi,

I have a '73 Riley Rocket and seem to have an issue with the Rear engine.

In cruise anywhere up to around 15k, the rear engine CHT is more or less on the top limit, thus I need to keep the fuel flow rather hi and in some conditions need to pull the MP back.

At the same MP as the front, I'm having to use an extra few lb per min to keep the rear CHT in the green, and eventually I have to reduce MP on the rear.

The front seems limited by EGT not CHT, but the rear hits high CHT far earlier.

Is this normal? And if not, where would you suggest we look first?