I had a search and didn't find much conclusive about the issues with A series engines
I found a post about rod bolts.
Not an issue for me as I run ARP's
I found a post about valve gear
Not an issue for me cause I run YT rollers

What about the rest of the engine ?
Are the rods up to high rpm and hp ?
Do the blocks split the bores under high boost ?
Are cranks prone to breaking ?

I've never seen a broken A series...... do they break ?
And what ares need attention for big HP ?

only ones i've heard of 'breaking' as such are sprint car motors ...... big hp, high compression and heaps of constant high revs, often in the top end but i got no details to share
would expect to see something go eventually in that set up.

i reckon feral would be one to know the weak points of an A-series

there bullet proof

If you flat shift at extremely high rpm, ... & miss, you will very likely lose, or at least loosen the flywheel & bust the front pulley.

The fixes are many & varied & include doweling the flywheel, using select fit fasteners to hold the flywheel [zero clearance in the flywheel holes] harmonic balancer & a rev limiter. All of these things together should guarantee reliability, but any one should be a big help.

I'm thinking rod bolts and lifters are the weak points.

There are lot's of things that will break if there stock.

Piston can be replaced.
Rods can be replaced.
Crank well I'd say that could take 200+ HP.
Pushrods can be replaced.
Valve springs can be replaced.
Timing chain and gears can be replaced.
Lifters can be replaced.
Oil system well a dry sump can be used.
Valves can be replaced.
Roller rockers can be used.
Aftermarket fuel pump.
The block and head are strong just how there are really.

If you've got the money most parts can be replaced to make the engine bulletproof.

I'm thinking Rocker shaft and pedestal would be the weak point in a high rpm engine.I havent seen aftermarket ones of them.

What we've got is close to the hemi apart from the fact its not crossflow and the valvetrain, but that has shown the be a very bulletproof engine over the years.

Nothing is unbreakable. My mate had a A12 in his mums morris, it kicked a leg out of bed pulling out of a servo. Big bloody oily mess.

The only bolt I've been really been given trouble by is the one that holds on the cam gear I sheared one in half, when the bottom end let go.

Noooooo.
I don't want to read posts like this.

My engine was overhauled by my dad and I a couple of years ago and it now has +- 50 000km on this.
Now the big worry after reading this.
We replaced ONLY the head bolts and used the same conrod bolts when we assembled everything.(This is in the bolts department).
I have heard that bolts stretch and must not be reused.(Only heard this a couple of years after the engine was back in the car and running)
That is why head bolts must not be reused.
But, my engine sees once a month AT normal operating temperature 6000rpm.
It is stock bottom end and was not balanced.
Must I expect a conrod flying out of the bonnet because we reused the conrod bolts or is it not a problem.

Sorry if I hijacked your thread dattoman.

If you read through the workshop manual, you will not find any recomendation to replace either the rod bolts, or head bolts during a standard overhaul, unless they are faulty, damaged, or outside service limits in some way.

Millions of engines have been rebuilt with used rod & head bolts during the last hundred years or so without a single problem, including all of my Datsun rebuilds.

If you are building a 'balls to the wall' race engine, then high quality, high strength fasteners are a good investment, but there are plenty of winning engines still running perfectly good recycled fasteners without tragedy striking them down. If they aint cracked, stripped, or stretched beyond limits, then they still work fine in normal service.

In a stocker, even a GX stocker, you will be fine too.

Yeah Dodgeman is right dont get a good gearchange at high revs and the flywheel will fall off. Also Ive seen a oil pump go on a sprint car engine and the guy still finished and won the race with no oil pressure. He even drove the car back on the trailer at the end of the event. Upon inspection the crank bearings got so hot they melted like solder into the sump. Jeff basically just changed the bearings, pump of course and did an inspection of the the rest of the engine and she lived to fight another day. good ol' A series.
(By the way this is a 10,000rpm machine)