Slow 1Y....why???

[Chopper]

I recently swapped out my sick 1Y for a fresh one but it's not as powerful.
I've just done a 600 mile trip on it with no overheating issues and the motor did not miss a beat.
It used to cruise at 65/70mph now it barely tops 55 with very slow acceleration!!
Also, it doesn't start as easily with initial clouds of grey smoke.
I've very carefully set the the cam and pump timing and checked it thoroughly.
I'm assuming that it's a fueling problem so I'm planning to take the pump and injectors off the old engine and put em on the new one.
Is there anything else I should look at??
All help would be appreciated.

[armyphil]

I'd get the compression tested, sounds like it if your getting grey smoke

[Chopper]

I've no tester for that unfortunately so I'm burying my head and hoping that's not the problem!!
In the mean time I swapped out the pump and injectors and spent an age setting the timing and now it seems way better.