well done… my kinda guy!
To help the 3.4 against 3.8 and 4.2 cars you need every bit of breathing you can get.
It looks like your carbs are just plain flanges under the mesh. Carbs will flow significantly more if you avoid that flat face and 90 degree corner by fitting some kind of radius. Assuming there’s no room for even short velocity stubs, try making a plate, say 1/4-3/8 or 1/2 thick and radiusing that.
If you look at even the emissions controlled S2 E-types and XJ6s, the bore of the flat emissions air cleaner box is pressed to form a radius. Same thing done in different ways on triple SU plenums and S3 V12s.
Guess you have higher priorities, but bear it in mind. From memory there is something like a 15% drop in max flow with just a flat face and since it’s a track car you’ll use WOT a lot.
Think your talking about my carbs Peter , not matchhlesspat’s 
Mesh was a temp job , I have pancake filter’s fitted now !
Yes, not my carbs but good point well made! I am building a “fast road” car that may see some track day use, I intend to fit the 3.4 / 3.8 air intake manifold that goes with the large flat coopers air filter, and fit the filter for road use, I am moving my wiper motor mounting area out by 30-35mm to get some more room as the HS8’s are around 30mm deeper, The 3.4 five speed series3 chose me by being offered on Copart as accident damaged (very rusty) salvage just when I was looking around for a larger engine for my 240, I am fitting it as is although I may check the bearings IF I have to swop the oil pans over,
I found with BMW straight six M30 engines that the original smaller capacity engines were the sweetest, smoothest engines, say a 2500cc or 3000cc against a 3500cc, much more power from the 3.5 but harsher!
Does anyone know if a series3 oil pan fits straight into a Mk2?
I have the alloy 240 pan and a gasket set on standby!
today is n/s/r 1/2 door skin day, without removing the door! if all goes well!
Pat
No need to change the sump , holds more oil too 
Looking for a basic set up for the front suspension for fast road and limited track day use, castor, camber and toe, I have also seen where someone inverted the upper wishbone mount, this would have the effect of lowering the pivot point therefore introducing an increase in negative camber when the suspension is compressed, i.e. when cornering hard, I have GAZ adjustable shocks, cut down 420 front springs and all new old stock rubber bushes (not a lover of polybushes)
Think you may regret keeping with rubber , I fitted a new set of rubber bushes , car sat for about 15 years , the bushes had splits all in them , from just sitting , I did not do the nut’s up , so they was not twisted .
Fitted poly and I am very please with them , and hope never to have to change them !
The new rubber is not as good as the old .
I agree about new rubber being poor quality as a general rule, most of mine is N.O.S Metalistic brand and it may last ok, I had a BMW 2002Tii with polybushes, it creaked and groaned, had a harsh ride and the wore the pins out, I will reserve judgement on the rubbers, getting old so a compromise between handling and ride is the order of the day,
seriously thinking of 205-65-15 tyres for my 6J 15 wheels, I like the look of your 215-70-15 with regards to filling the arches but feel there may be some disconnect with the tarmac with such tall rubber, also still unsure what steering I am fitting and would like my wife to be able to drive it as it will be ULEZ exempt, thoughts guys!
I did my whole car in poly bushes from this company called SuperFlex - they say they adjust the hardness of each bushing specifically to fit where it’s used, so the suspension maintains good ride quality etc. while being stiffer and more stable. Have had them on my car for 5+ years and never a single squeak.
I think your find most MK2’s have 185-70/15 , 65’s just don’t look right !
Std was 185/80/15 but as I am going up to 205 wide 65 profile would be a similar height, the profile is a percentage of a full height tyre, 80% being the largest normally available although my 1929 Dodge has 100% tyres, 550-19 on wooden wheels,
so a 205/80/15 would be a lot taller than a 185/80/15.
I may well go to poly bushes in the future, especially at the rear but for now going with the rubber I have been collecting for the last five years,
Mk2 front suspension X members, are they different for PAS / Non PAS, what is the opinion of the Adwest Marles pas box for spirited driving, compromise needed as my wife will also use car now and again due to ULEZ exemption!
Yes they are diffrent , PAS in picture , see right hand side , slight dip so box can fit , easy to do yourself on a manual frame
This one is on e-bay at £150
Steer clear (sorry for the pun) of the Burman assisted unit. They have a torsion bar in the column that restricts quick changes of direction (think moose avoidance) when I first had my ‘66 ‘S’ I did a slalom and after the second or third the steering started to load up and act as if it was a straight manual box.
I am looking at an Adwest / Marles unit, not the one with the round top, I guess they can be repaired as they look the same basic design as a Land Rover or London Taxi?
Sounds like any rack and pinion unit, where the torsion bar regulates the oil pressure, and when it breaks, your assist is gone and it is like a manual box?