i am no longer entering into this debate, as a member of the motortrade and having worked in motorsport (preping mk2 rallycars as well as grp N fwd rally cars) i feel my input could be valuable but if nobody is going to listen to me i feel i am wasting my time, if anyone would like my advise on this subject ask
I have to agree with you, all engines benifit from these mods, although to perhaps a lesser degree. I too was involved with motorsport and modded a few engines and vehicles.
It's not quite as simple as grinding out ports and bigger valves tho, some engines are blighted with ports too large to start with.
I found, and its one of the major mods is to match the manafolds to the head. Take a drill and drill through the manafold into the head, but not into the water jacket, fit silver rod which makes sure the manafold always fits into the same place, then mark the two surfaces and grind out the surplus metal until they match perfectly.
In relation to the valves, you need to see if the breathing charactistics of that engine requires bigger valves, however you can improve the flow if you grind away the section of valve guide that sticks down from the inside of the port, but it reduces the life of the guide since it's shorter and can't do the job as well. I also cut 5 angles onto the valves giving an almost curved profile rather than the sharp restrictive one. Continue onto the seats and use a radius cutter which will give you curved seats then much better flow.
I have seen many heads fooked by maniacs with grinders, you need to know where to take metal off, how much, and have a means of measuring the amount, usually with fluid.
In relation to the timing most are miles out and the only way to get it correct is by fitting a vernier pulley or offset dowels, and off course the distributor fitted standard is ****e so a decent one is also required.
Then a camshaft and followers and valve springs, and it goes on forever depending on what you want to spend, but the more tuned it becomes the more unreliable inevitably it becomes, with engines that wont idle below 1500 rpm and often a bastid to get going.
Oh one other easy mod, lighten the flywheel, fokin tonnes of metal surplus here so there is, probably fokin tonnes on the landie con rods aswel, and the crank, then off course there is the balancing bit.