The problems you will run into keeping the VA going will be parts not similar to the 8/1. There is a fin cooling coil that attaches to the injector. No known source for that. The engine will run without it.
While it is correct that this part is no longer available, its not a difficult item to manufacture (from a pattern), as it is a non wearing part. Although not missing on my engine the fins were well damaged, so I manufactured a replacement from Copper as I had a suitable sized blank, and it offered increased heat transfer.
Yes you can run the engine without it, but oil and grease will tend to leak down the engine from the rocker gear onto the finned cylinder head surfaces, which is not good for engines operating long hours in hot and dusty environments, as the dust will stick to the fins and significantly reduce the cooling effect.
Other observations that may be of interest:
The cylinder head gasket (3-30-31), and bumping shim (8-30-32) are both still listed on Sleeman and Hawkens website, so should still be available.
This is a far less complex gasket set than the CS watercooled version so I am surprised the likes of SEP are not selling it.
Why sleeve back to STD when oversize 8-1 pistons from India are available, as sleeving back to STD is going to cost far more than a rebore (after sleeving you might even need a new STD piston as it may be worn, particuarly in the top ring groove area beyond further use). By all means sleeve back to STD when you have exhausted all the oversize options.
Other common parts:
If you dont mind dispensing with the lifting eye on the rocker cover, then the cylinder block studs from the water cooled CS can be used in their place.
The rocker gear is identical to the CS version, but it is configured slightly differently using two instead of just one rocker pillar.
Both valve guides are the same, and are the same as the CS exhaust valve guide.
The fuel filter is usually a Crossland item which is the same as used on a host of later Lister and Petter engines.
Not surprisingly Listers raided the parts bin for bits when the originally designed this engine, as there are also parts which will fit from other Lister engines as well: If you are unfortunate enough to have one with a rotted out flywheel fan cowl, as I had. You may be surprised to know that this is very similar to the Lister HA2 and HA3 engines that have a sheet metal fanshroud, and this item is easily modified to fit the VA engine, and by default the cast iron fan impellor which bolts to the flywheel is also identical to the Lister HA2/3 equivilant.
The fan shroud side flywheel is also similar to the Lister HA2/3 version, but is not interchangable due to differences in the design of the hub, and in particular the mounting arangements (taper verses key).
The paper element air filter cannister is also a Crossland item which is the same as fitted to Petter PJ engines
