i only spent $1500 on it, in '05 and my job paid for it ;) what it really needs is roller rockers...

mine? i plan on turboing, so it didn't seem as important, and it's easy to change heads when i get one.



basically i figured i'd go for the low end torque over topend. I've been optimizing drag on the engine, light weight crank pulley, lightened flywheel, electric fan. You can feel the few pounds less in rotating mass. If you feel brave, disconnect the alternator and go total loss ;) the ignition will run down to 6 volts or so...

But as you can see by the mods, it's an experimental vehicle. It's always ben planned to have a turbo added since I switched to LPG, it only burns LPG so it needs 12:1 compression, then it screams. The high octane and good fuel mixture ( it's a gas already, so at low rpm it's way more responsive than petrol - part of why the round ports ) it goes! the acceleration profile is different than with petrol, it likes planned continuous acceleration, with a spoon full of extra fuel once it gets up above 4000 rpm rev limiter comes in at 6250, only ever hit it once, don't have a tach, it sings.

it's totally a work in progress, i have the fuel tank out now working on a better mount and provisions for a bigger one.

not a drag car, but not likely to be passed on the highway unless you like to drive faster than 94 mph in a 65. ( lol highest official top speed - flat ground overdrive 5'th not in the powerband really, need to go faster@ )

looks like someones spending money on that motor..... why has it not been upgraded to oval port????

I think that you have it pretty much all stitched up.
This head was used on the economy version of the A14 but I suspect that the A12A used a head with small OVAL ports. Those valve sizes are the standard A14/15 diameters, so it's obvious that standardisation was a term that Nissan lived by with good results.

Most, if not all, of the heads that feature the double top studs for the inlet flange, also have the hole drilled & threaded between the ports for the earlier, round port manifolds. I don't know why, & there must have been a lot of holes needlessly drilled & threaded over the years, but that's what they did.

As for having larger exhaust ports, well, only measuring will reveal the truth, but I suspect that they just LOOK bigger by comparison to the little round inlets.

In a light car, like a 1200 2 door, one of these A14 economy engines would serve long & well as a daily driver, delivering satisfactory peak-hour-traffic performance & exceptional economy to boot.

It's horses for courses, & Datsun had the right horse in it's stable for just about any course, & were a frequent winner in the 'Economy Stakes'

yeah i figure it's nothing special.

it must be a later casting of this:

A14 Round-port head
Intake: 37mm
Exhaust: 30mm
Has round intake ports (like the A12 head). Casting numbers are under the valve cover area: "990" towards the rear and "454" towards the front. This is the head used on A12As and some A14s. These cannot be ported out to match the oval port heads (you'll hit a water jacket). These can be found on some late A14s, like 1980. It has two small coolant holes below the intake ports, to provide heat for the intake manifold. These came on the "GFU" and "MPG" cars (USA-market B210 and B310 fuel economy champion models).

i once upon a time had all that emissions crap, but it fell off somewhere.

it looks like that head has bigger exhaust ports than some of the others. maybe not.

i know i ported the intake/exhaust manifold and gasket a bit to make it match better ;)

My old 1000 ute had a head like that with the extra hole for the studs like that. It also had the emmions thermostat housing.

I found out it was nothing special

i was jsut looking at pictures of the head on my engine... Don't have any with the head off, but i was noticing it has the hole between the intakes... I thought only GX heads had those holes for the other studs...



the head is H990 - 459 round port. never found anything out about this head, I assume its a round port swirl low comp head.