Does anyone know anything about A series hybrids? Eg A12 block with an A14 or A15 head?

Also whats the biggest carbs that'll run good on a A12 cos i just pickd up a pair of 42mm Dellortos

toddat1200

Just keep it revved up ...

42's are great for 1300cc engines. 40mm sidedrafts wont keep up with a strong 1300.

A 40mm carb seems optimum with about a 30mm choke, so you could start there, and have the option to go larger if you need more top end.

Check the compression ratio with the later head, the chamber might be a tad large for a 1200. You can skim it down to suit. Something about the oilway being different rings a bell too.

How about those carbs on a stock A12, the only mod being extractors.??

hey todd,

my 42 webers had 32mm chokes, and with my modded 1200 motor they are too large, they need 30mm chokes,

so id say you need 30 or less even if possible

also what tsillay said aout the heads, they will bolt on, but you will have less compression (good for turbo )

there is also diffrences in the water jackets that go into the inlet manifolds, some have em some dont cant remeber which ones though, and yeah oil delivery diffrences rings a bell for me too

i have an a-14 block that you could try out, theres an a-15 block at pick a part too, or how bout the entire a-14 in the car in your front yard why not use that?

My $$$ sais the 42mm carbs will be fine,I have a set of 40mm webers with 36mm chokes,they have run perfectly in a wild A10,mild A12 ,warm A15 and a warm L20b, all with only minor tuning adjustments.

When Weber/Dell'Orto/Mikuni and similar carbs are being used the old, old rule applies.

You can always tune an over carbed engine (by altering choke size) but you can NEVER tune an under carbed motor.

This is another way of saying that sizing for constant depression type carbs (SU, Stromberg CD, Hitachi) has to be more precise.

36mm CHOKES????

crap, i cant believe that, my car ran like absolute crap under 3500 with 32s and i had em tuned up, ran beutiful over that but yeah under that was an absolute PIG

I don't want lower compression!!!!

I've got the options of A12/14/15 bits galore! Can i stick together a combo, preferably with a A12 bottom end that'll haul???

not really with the a-12 bottom, your best off just having a GX head for it (a-12 GX that is) so um put simply no

just carb it and hurry your arse up with the a-15, i better get turbo on mine before you finish though otherwise sounds like ill be in trouble