OK, here's a thought to kick around. The bane of blown A series engines with carburettors seems to me to be the ignition timing. Everyone wants plenty of compression & plenty of boost, but few seem to do much about the ignition timing.

Not the idle speed timing, but the boost retard. As compression pressures rise, so too does the degree of detonation [knock], & it's this detonation that cooks pistons & rings, so here's a suggestion.

Grab a suitable aftermarket EFI computer, a TPS, & plumb in the MAP sensor. The TPS can be fitted just about anywhere that you can make it fit & reliably work, & use this thing to control only the ignition timing. You could also use the temperature sensor & anything else you want to add to make it more reliable if you wanted to.

This means that the distributor will need to be locked up to eliminate any advance coming in at all as it is now just a TDC signal provider, & of course it distributes the sparks.

It will need to be mapped on a dyno as per a regular EFI, but it should work a whole lot better than many of the systems in use now.

Lets face it, a used computer & some dyno time will cost a lot less that your next four blown up engines.

Just a suggestion for discussion.

and a very good suggestion too.... Timing is indeed the more important aspect of tuning... it is also a lot more complicated to get right. Even some pro tuners with topnotch dyno's have trouble getting timing sorted properly. So much so that I've had to discard a Paid4 map on one of my friends Bantam 2l EGI's. they charged him for a map with dead flat timing at 21

My suggestion was for people that already have carb equiped blown engines [either turbo or P.D. blowers]
I agree that full EFI would be the best proposition, but for some, economicly, that's just a bridge too far.

My suggestion will still not be 'cheap' but detonation kills far more blown engines than most people realise, & it can do it in just a matter of a few combustions under the worst of conditions.
Some people never find the money to do it right, but seem to find the money to do it over [again]

Just on piston selection, I used pulsar et in my a14. No mods required. Not sure how they would go in an a15.
Being designed for a turbo they had thicker ring lands and decent rings, also a deep dish in the piston. Probably a bit to deep. It was a little bit sluggish off boost.
A cheap option any way.

dodgeman.. thanks for stating what ive already done.. hehe... please keep on topic

ET pistons sound good, a14/15 pistons are same as far as i know

Yeah, but you run the full EFI system, so you're already ahead of the game. People with carbs dont seem to think too much about boost retard.

Proper timing under boost is what will help a boosted engine to live long, regardless of the method of fuel delivery & isn't this thread about long life [reliability] under boost? Water injection will also reduce detonation [there's that word again] & help prolong engine life.

A14 & A15 pistons are quite different. The A15 piston has a lower crown height to accomodate the 5mm longer stroke while retaining the A14's deck height & rod length.

it's about building a motor

but now your talking bout it you can get a factory electronic dizzy for a-series which has a diaphram on it that can be hooked up to run boost retard, i have one but i think its in pieces. came out in some US model sunnys.