Hi Roger, thanks for your reply and your information which backs up my theories.
I have also struggled with the personal mails, in fact I replied to one from Dave Hughes (Big Valve Head) but have heard no more from him and don't know if he received it or not. Dave, are you out there?
SInce my original post I have done some more internet and book based research and it does look as though all normal road Elans from the first S1's through to the last Sprints had the heater intake grille recessed into the scuttle top. The Series 2 26R's had no heater intake on the scuttle and there was no recess there either. I don't know about the series 1 26R's as I have struggled to find pictures of known original cars where that area can be clearly seen. Modern 26R replacement bodies mostly seem to have a recess, but usually the hole is not cut and the grille not installed. Maybe this is a handy trick for spotting replacement bodies on "completely original" 26R's? The car I am restoring has no recess but it does have a hole cut and a grille fitted. There is no evidence on the underside of the scuttle of any grp work to remove a recess and so I am drawn to conclude that the body is an original S2 26R which at some stage in it's life had a heater fitted. The car was based in Sweden all it's life and was used on the road latterly so this does make sense.
Before I try to answer to your questions I am by no means an authority on the 26R (23B's are my primary interest), this is the first one I have restored and as with so many things it's a case of learn as you play. The one thing I am certain of is there is a lot of bad information and non-genuine cars that claim to be otherwise out there so a degree of caution must be applied to everything you are told. If you know something that differs with anything I say please tell me, with luck and common sense we can then work towards understanding what is correct (in our minds, at least!)
The so-called high back chassis was I believe introduced on the series 2 26R. Although several people have told me that it was done purely to make installing/changing the diff easier I think this is wrong. The diff height on the standard Elan is such that the centreline of the output shafts is around 5.5" above the bottom flange of the chassis. If the car is fitted a tyre with a rolling radius of 11.5" such as a 5.50x 13 as fitted to the s2 26R then the driveshaft will only be horizontal when the rear ride height is 6". If the car is run at a lower ride height such as 5" as specified for the 26R then the driveshaft will be angled upwards as it moves outboard and this will give a small but significant power loss. Lifting the diff will reduce this loss and I think this is why the high back chassis was introduced. Certainly in my experience Lotus rarely did anything purely to make the mechanics life easier....
As I said my car doesn't have the high back chassis but I will be fitting one in the restoration. The body suggests the lift in diff height is about 1" but I will confirm this when the new chassis arrives. The lift is achieved simply by mounting the diff upper crossmember higher than standard so there is a step between the upper flange of the two diverging panels either side of the diff and the top of the upper crossmember. I assume that the strut turrets must be commensurately shorter to keep the strut tops in the same place as mycar is fitted with a standard chassis and the upper body to tower mounts look to be in the normal place.
I attach a picture of the underside of the body that clearly shows the raised section to allow the higher crossmember to fit.
Congratulations on your list of cars, I assume the ex-Yamura 20/22 is one of the ex-Jim Russell "Grand Prix" cars? Lovely.....
Best wishes, Nick