When I placed the headgasket from a 1600 head onto my A12 all seems good just need 2 and 3 bores offset machined inward to clear one inlet valve at worst a little nothing will do the job just like the big valve headed A series heads.

Anyways good news is Ive been informed the kits are ready to go, these took a long time to sort out and you get all the hard work done and sorted by the pioneer when you buy this kit which just covers the time and a little on the side for the effort.

You will need to bore for your A12 for 76mm daihatsu pistons for the HD or HC series engines or use the stock Mazda b series pistons for the A14 and A15 blocks.
Im building my first twin cam A series with the Daihatsu pistons, using the copper/composite gasket already to go, the block mods are just on the water and oil galleries, the seals are supplied for the camshaft and crank areas, you use your stock sump, rework some water galleries on the head, tap and insert some brass fitting to drain the oil from the head to the distributor cavity. Use megajolt junior or other crankfire ignition system for carbs or stock mazda ecu for all the injection from factory.

Will put up a more detailed description for those purchasing the kit
for now there are 3 kits available I have my name on the 4th so please
contact me if you would like to purchase the kit and so I can work out
postage cost to your door etc.

The price of the kits are 900aud for the front plate which also includes
cam and crank cover also camshaft drive attachment that uses the factory
mazda cam belt pulleys. The headgasket to suit 76mm bores is 160 aud.

It could possibly fit 77mm bores but will need to be remade for 78mm however
all the work has been done by the designer for you and is a great price for
using it as a template for when you get more made at your local gasket maker.

Please also consider the maker of this kit was asked as a favor to make these
for everyone here and he is only getting a small profit for his time/materials.
He doesnt have a business or internet to speak of and I will help anyone with
questions or technicalities that you might ask.

With 10.5:1 compression, dual exhaust camshafts ground from factory 235 degree
and 8.5 mm lift exhaust cams to 260 degree and 9.5mm lift, 2mm shaven B6 head
with aftermarket headers and quad 45mm bike carbs or 45mm efi tbs there is
160hp available at the wheels as done by countless Miata/Mx5 peeps.

Thats way more than any GX head can make as a daily which is what these mazda
machines are making reliably day in day out.

The belt driven aspect also saves some rotating weight from the chain drive
and the A series crankshaft is lighter than the Mazda full counteweight units
and should therefore spin up a little faster through the revvs all else being
equal and the A series timing cover is longer needed.

Pic below shows 2 front covers and a HG as you can see the sump extension lid
or cover has been tig welded so peeps can use stock sump with no mods.
More pics to come from other side but takes time as my fossil style phone takes
quite an effort to move the pics onto the pc.

For now Ill call this hybrid the BAT engine
eg. B for Mazda B series head, A for Nissan A series, T triple cams :)
Worth noting for a bit of history Cosworth/Lotus used the Kent motor in the
same configuration with the OHV camshaft to drive oil pump etc.

more pics of earlier pages
http://datsun1200.com/modules/newbb/v ... ASC&type=&mode=0&start=10

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