If you are on a budget which like most of us you are you will only make the most out of anything that you do if you provide in your budget for a rolling-road session. I know it seems like money for nothing but it will benefit the performance and the engine longevity.
I would recommend Dave Young of Mech-Motorsport in Cheltenham but he could be too far for you too go to.
The problem I found with some other rolling-roads was that most places dont stock the complete range of jet parts too optimise your performance, top - middle and bottom for the IDF carbs.
Removing the standard airbox and fitting free-flow airfilters will assentuate the rasp and release some BHP on runs. If you are in traffic a lot effect will be reversed as they will be pulling hotair from in engine bay.
Carbs have to be
synchronised. Check that on the linkage the butterflies open at exactly the same time and by the same amount. Check that they open fully to the correct position on the throttle pedal aswell as on the linkage.
Start putting some redex through the fuel system to remove carbon, petrol lacquer and other deposits.
Make sure the ignition system is in good working order; coil, lead, cap,rotor arm, plug leads, plugs, gapped correctly.
Does anyone know if the bolt spacing from a 16V exhaust manifold fits the 8V head. I know its at 45degrees instead of 90 but if its the same at least you could just cut them off, turn and reweld. Alternatively weld on 8V flanges to a 16V manifold.
Fit a 16V system as I think overall it is larger dia. I usually remove the centre box. Bit less weight and again a nicer sound
Just some basic low cost thoughts alot of which can be sourced of ebay.
Good luck rsfruitbat