I've just recently purchased a mini and need help identifying the engine. The engine number isn't consistent with any numbers I can find. It starts with 'N66' and finished with a 'P'.....very confusing! Any help would be greatly appreciated.

It is a "Police Number" That is a new replacement engine number issued by the Police when a number is damaged or gone missing.
First digit, N = NSW
Next two digits is the year it was issued, 66 = Year
Next digits are the sequential number.
Last digit, P = Police.

It does not mean the engine was out of a Police car.

The head looks like a small bore head, so probably a 998 or 1098.

Thanks very much for that, it certainly had me scratching my head. It's been 25 years since I last had a mini so I was very excited about getting this one. Still trying to work out year/badge etc. It's badged as a Deluxe but I was surprised to find the compliance plate has body type YKA2S1 indicating it may be a Cooper. Can't find a number around the engine shroud but if it has in fact been a recovered stolen car (as the engine number suggests) it could explain this. Here's a pic.

Looks like a Mini Deluxe on Hydro

Yes, windscreen wipers are on wrong side to be an early 997 or 998 Cooper....but I do see Cooper wheel trims and Cooper Stainless Steel Side trims. Maybe its been reshelled?

Hold onto those side trims, they're in quite a lot of demand for early restorations...

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

When you look closely the wiper plinths are in the correct spot for a cooper but it has the incorrect arms on it you would be better lifting the front carpet and seeing how the floor is where the 850 gear stick hole would've been factory blanked or the striker catches where they mount on the body put pics up, does it have discs, but I did see a hydro fitting in the engine bay

Police also issued these numbers if you bought a NEW block or motor from BMC back then.
I bought 2 like this back in the 60s, a 1098 block and a big journal 1100S short motor- they both came with NO numbers stamped on the block.
The cops then gave you a Police number when you showed the receipt, they told you where to get it stamped, then they checked it was done correctly.

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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.

Wow, thanks for all the info!! It only has drums and it currently has hydro. I'm working this weekend but I'll try to get pics soon of under the carpet. I again appreciate the help.

Check in the boot. Does it have mounts on the back of the seat for a boot board or is one fitted?

This is a good way to ID an early Cooper. (check they look neat and factory)

If you have a photo of the whole engine bay I can probably work out a rough year based on bits and stampings.

Hi guys, I've attached some more photos of the engine bay and of the boot. I have since found a stamp on the chassis just below the plate with the last 3 numbers of the car number matching the stamping. I can't get to under carpet yet (without removing seats), am I able to see the cover from under the car if its on a hoist? Thanks for all the help again!

ID plate says Cherry Red & Smoke Grey - if my eyes read correctly.

Definitely could be a Cooper, as no Deluxe came with this colour combination.
(Or at least it's a Cooper ID plate!)

If it is a Cooper it would be an early one.

Is there a number stamped on the firewall just below the ID plate?

Yes, there's a 3 digit number stamped into the firewall under the plate. It is the same as the last three digits of what's on the compliance plate.