Well after playing for a while with a supercharger manifold I made up for
my AMR500 supercharger and not being happy with the pulley arrangements
and having to start again I decided Id do a single SU manifold first.
I used some advice to try and improve the pulses using full radiused velo
stacks (solid) & lower roof on ends to make sure 1 & 4 inlets get same air.
If enough interest and prices are right for local casting I might consider
casting 6 or 8 of them. I wanted the old look to suit the era etc.

Here is the start using sch 40 steel for prototype which will be refined over
next few weeks for a quotation. Much time spent working out clearances for
su over exhaust system and also could be used for injection or LPG.
45 or 90 degree extention to inlet can be added for facing car/throttle towards
the front and improve torque slightly or for different layouts.

1st pic is of drawing for prototype
2nd with massive 2 inch SU
3rd with decent 1.75 inch SU
4th is just plenum
 
 Big 2 inch SU or 51mm of roar!!! : )
 
 Still beef, 1.75 inch or 48mm of growl
 
 plenum close up , 4 pieces of painful work

Thank you, lot of work for so little but need to get all smooth inside.
 
Will be 2 piece so people can further smooth the insides if need be then
bolt it back up again with some sealant or weld it up if need be.
Would be easier to cast and plenum can be re-used for other engines
of similar size and just change the fist halve of the manifold.

Thanks Dundee, Ill make sure I get everything spot on perfect so if prices
are too high for casting I will have a good one off
 
I got to say the 2 inch SU looks awesome in real life been so big but fits
nicely in the bay and is very light for what it is, lighter than stock hitachi.
The 2 inch inlet & 2 inch wide 14 cm long throat look impressive from side
view like a big cannon, will be nice w/ 76 bores and modded A14 crank A12.