Should I or shouldn't I?

Hi, FarmerFred.
Re boosting the early 47A to later Hi-horse 47A 'grunt' capacity, it is my understanding that the turbos were different as well. I am pretty sure that the later units had a smaller bore turbo with a higher output and efficiency to match the altered fuel settings. These same turbos also had a larger exhaust outlet that connected to a larger stack to allow better exhaust outflow. I also vaguely remember a different air cleaner being fitted.

On the 'Love-That-Sound' side, they also had a somewhat deeper 'bark' than the earlier tractors.

Some of the more 'technical' people will likely chime in here shortly with possibly better info on this topic.

Just my 0.02

I think from memory the dead axle was smaller on 160hp tractors.

Cheers djcat

Sounds like its running like it should. Turning it up and rolling smoke out the stack isn't the best for the engine, you just waste fuel and wash the cylinder liners and reduce engine life. The turbos are the same for the low and high horse just the elbows were changed for the dust ejector system for the air cleaner. The early sevens had the old style turbo like the 17as but the replacement turbo is the later style. Rpm for the low horse high idle is 1325 and the high horse is 1350.

There is a difference in rack settings also.