I am looking at buying a bored out 1380 head and some 1:5 roller tip rockers for my 1993 Spi automatic mini, Do you guys suggest this is a safe thing to do or will i end up stuffing the gear box up?

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The 1380 comes from the bore, not the head, so it'll just be a ported 1275 which will be fine.

really the guys at minispares uk said it was 1380??

Would you have a rough idea on HP gains by any chance?

Just remember that a hot auto has less power output than a hot manual , all the people I,ve talked to said it's better to focus on torque than horsepower , with the earlier auto's there is a mod to change the shift patterns to get it off the line better no so sure about the later ones , the formula for an auto is pretty simple - maintenance, 10 inch tyres only , mods to improve torque

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I have the standard 12" tyres and its driven like a manual 1,2,3 D and i get more power out of it that way.

Whats the best way to increase torque?

Apart from power loss due to the converter, the other problem putting performance modded motors onan autobox is that 1st gear is tall
(2.69:1) and the torque converter is only 1800rpm stall.
So, if you stick a big cam or ports in it, it'll be a slug off the mark, until it's on cam and breathing properly. Meanwhile, everybody else with manual boxes has disappeared into the distance.

As an example, Greig Malaure's GF has a 1430 stroker with RE13 cam and HS6 carb on an autobox, it made 112HP on the engine dyno. However at our Mini night at WSID, it was only doing around 18s.
[edit] and this was with 10" S wheels on it too.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I am sorry Dr mini i don't understand half the things you said :/ I have a lot to learn.
I don't want a 10second 1/4 mile car just something with a bit more power. I want to try and get the K & N cone filter but apparently they do not fit on automatics as you need an extra sensor.

Basically what I'm saying is, if you fit a head to an automatic with big ports and valves, or a big cam (or 1.5 rockers) it'll be slower off the mark, not faster...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Ahh ok i won't do that then. How do you suggest i get more power out of it?
I have already modded the airbox, Changed the exhaust and manifold.

Just recondition the head you have , get it shaved to give you between 9:5.1 to 9:7.1 compression ,double valve springs, use a kent 274 I cam and Isky lifters , use 98 premium fuel and just drive it , the Rover SPI Mini's are a great comfort road car end of story , yes people do spend money on say a UMS ecu with a wideband lamda sensor and some time at the dyno but at the end of the day , you bought it to drive it, so some simple mods to make it a bit more driveable is all you really need

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Thanks Snail and Dr Mini, I will take all that into consideration.
I bought a specialist components ECU and the mini did not like that :/

Danny, didnt you mention you want a manual anyway? Id save the money trying to get an auto to go quicker and just spend it down the track on something you really want. Or in the meantime, unbolt all the A/C fittings etc, that Rovers have stashed under the hood and you will lose 20 kg right there

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I would like another car to be a manual
I have taken everything out to do with aircon apart from the compressor. I need to find some alternator brackets and belts etc etc so i can use the alternator without the compressor.

I'm not sure about 60s / carby engines, but with the injected ones, auto engines are different to their manual engines from the factory in more ways than the obvious: quite often they ran lower compression setups and a different cam in oder to get the engines torque low in the rev range. Factory claimes 63 hp on the manual cars, but autos only got 42.

Basically, to get an auto to go faster you'd need the worlds smallest turbo so that it hits boost before the torque converter kicks in, either that, or mod it however you like and replace the torque converter with a normal clutch for power starts!

sorry for the blatant off topic..

is that how the 'semi-auto' vw's worked? clutch for off the line then just bang it through the gears?