http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=50278PJZ often gets 73mm forgies for cheap and some can be milled for flat tops.
A guy I bought stuff from who does up rotaries but prefers to drive for his
everyday 250km round trip to work for obvious reasons has an 74 LPG turbo corolla.
Its supposedly bullet proof and has about 140-150hp at the wheels using the 1.5
pushrod 5k with diminutive round port heads open up for more flow.
The A series oval port heads kill the toyota ones and he uses the right angled Impco 200
with an intercooler as the straight feed impco 225 blow its seals.
He is in Gippsland and is full of hills and bends so the car is set up well for handling.
The impco 200 would be your best bet but what he has done with the rolla motor is a custom
inlet manifold with very long runners for extra torque which is the Achilles heel of the
A10 datsun engine and would benefit clearly for such a setup.
Is there a reason you are not using an A12 to meet the U2ltr capacity? Dont get me wrong
Id love to see and A10 turbo LPG. Its just that the a12 at 1179cc x 1.7 is perfect and
the 70mm stroke makes a bit difference.