Hi Buddan,
The easiest & most effective way to get better performance would be a displacement increase to 2.5 litres. That adds torque & HP everywhere in the RPM range.
Since your case needs to come apart for the rebuild and receive all the necessary machine work on these Mag cases, its not difficult to modify the case to accept 90mm P/C's.
I've done quite a number of these over the past 40+ years and it makes a very nice driving car.
