New to building Barra’s.

[Sandman]

Hi, I hope I’m asking these questions in the right place. I’ve never had anything to do with building a Barra, although I have been building hot street and race engines, Na and blown for over 40 years, but mostly chevs. No EFI etc.
Anyway, my stepdaughter has been racing her BF utes, she has a 6 cyl Barra NA with auto, and a 260 boss with 6 speed. So now she wants to go faster. So I suggested we work on turboing the 6cyl. I was told the NA rods are weak, so I reckon the best idea is to start building a second engine.  Aiming initially for 350-400rwkw, but build it strong enough, so that it can be cranked up some more if needed. 
Do I need to find a turbo block, or are the block and crank the same as NA? 
At what kind of HP level do I need to be looking at a girdle for mains? 
I was looking at Atomic engine kit, with good rods, forged pistons, oil pump, head bolt upgrade etc. Anyone have any comments about them? 
I also see that the NA auto boxes aren’t good once the HP goes up. If I use a ZF box, how compatible are the electronics? 
 

I like to have my engine and driveline combinations worked out before I start buying, building anything. I’d rather do it once and right first time. So as I find out more, I’ll probably have more questions. And if anyone has any good advice of what to look for, etc, feel welcome to add your comments.

TIA
 

[Puffwagon]

Block and crank are the same, there are different dipstick locations on various blocks. BF head is a good base as they have a better combustion chamber design for high hp.

As far as a girdle goes, you can get away with lots for a while. If you are building an engine it is a no brainer to chuck in a girdle for the extra $1400 or so it cost for parts and machining. It'll keep things stiffer which is always better. ARP mains will be used, line hone is needed, caps machined down to fit girdle etc.

I've personally taken a spool I beam rod and Bullet series piston with upgraded pins to 1100hp at the crank with no mods, and then again to 1350hp at the crank with a skirt and crown coating. Same exact pistons used in both cases.

Stock oil pump with gears, relief spring and backing plate will do the job. Keep the rpm under 7000 for reliability. 12mm ARP head studs will be fine for this build. You want oversize washers with the studs as the ARP ones are too small.

An auto box will not like racing unless it's drag racing or roll racing. You'd be flat out keeping the heat out of it on a circuit when it's making bulk power.

I've got a thread over on the xr6turbo forum that shows most of it. It's a long thread but it's a good read and there is tonnes of good info in there, the good and the bad.

Finally, I've somewhat recently built an engine for someone that has similar specs to mine but a budget build. It came in at around $12,000.00 for parts and machining. Bolts ons like fuel system, manifolds, turbo etc can all be added to that and budget another $15k. A built zf will be another 10k and then you can expect some tuning and fluid costs along the way for about $1500. There's shafts that need upgrading, diff, brakes etc. I tried to talk my mate out of doing it cos it cost me over 40k for my shenanigans (home built and tuned), he still went ahead and spent 25k on the engine side of things and still is going to spend the 10k on a trans soon.

That said, read my thread, do more research and if you've got questions after that, I'll be happy to answer them.

[Sandman]

Thank you

[Puffwagon]

No worries