new engine for my spitfire!!

Do you want to "keep it in the family" so to speak? i.e Austin Rover/BL?

Does it have to be DOHC/16 valve or are you happy with an 8V/ Are carbs a no go or you happy with either carb or EFI?

How about a 2.7 V6 Honda unit from a Rover 827? I know they're FWD but adaptor plates can be bought / made. I think Mr_Bo11ox was tooling around with one and mating it to a LT75 (I think?!) gearbox for RWD fun.
Or how about a 2.0 Turbo from an 820 Vitesse? Highly tuneable and would be a right laugh hearing a Spitty go "Whooooommmmm-TSSSSSSS!!!!" ;D

Saw a RWD Toyota 16-valve fitted to one once, really nice installation, the guy had measured up most of the options and figured the Toyota was best, I think because the sump cleared the chassis. Really good tuneable engine by all accounts, and you can supercharge them

Sylva use them in kits, so it must still be possible to find them.

Don't know what the weight of it is, mind, but probably much less complication than a K

MX5 swap would be a good one. They are available in scrappys now so sourcing one shouldn't be hard. No idea what prices would be like though.

For cheapness an S12 Nissan Silvia turbo lump would be hard to beat. Scimitar SS1's had them and performed very well and they'd perform similarly in a Spitty. Very compact engine too. £100-150 should find a complete donor.

Edited to add; SR20DET's whilst an awesome proposition are somewhat pricey. You're looking at £800-1000 for an engine an box. You can sourse a non turbo SR from a Serena (135bhp) but you'd still need to find an S14 200SX box to go on it and that's the pricey bit.

CA turbo twin cams are a lot cheaper but finding a good one is hard. A good CA twink is an excellent engine for swaps. Small and light and very tunable. £350 should but a complete setup but you'll have trouble finding a good one. Neglected ones suffer premature bottom end failure. If you're not worried about big power you could always go for the non turbo version from a Sunny ZX. 129bhp and can be fitted RWD with a Silvia box. I just so happen to know where you can get one dead cheap too

I know there's pictures somewhere on-line of one with an RX-7 Rotary...... ;D

K-series would surely be a safe bet as there's so much aftermarket support but I quite like the sounds of the MX-5.

Is the MX5 lump alu?

yes, all ally. 1.6 puts a paltry ammount of bhp, the 1.8 is about 30 bhp up. gearchange is the sweetest ever. my boss had a supercharged 1.6, it went really well. prolly best to start with a 1.8 for the most hp out of the box.
I've seen the rotary powered piccies, I reckon it to be the way forward.
what about the venerable x-flow? tuned up it must be fun in a light chassis.
xe or ohc vauxhall? your options are almost unlimited. stuff corners, 500 cube caddy

don't be tempted to shoehorn some exotic lump in your spit, the rear end just wont take it. Trust me, a Spit or Herald on 3 wheels is not fun!

You could put a GT6 rear end in and the Triumph 6, there are a few "GitFire"s around like this but then you start to explore the outer limits of body flexibility. Ultimately you're taking a car whose ancestor was designed only to handle the awesome lack of power from the Standard Ten engine and you're expecting too much from it. Instead, just enjoy your little 1300 or 1147 for what it is, get the wind in your hair and have fun.

The 1500 is not as good. (edit: just noticed yours is a 1500 )Same block as the 948, 1147 and 1300, bored and stroked to within an inch of its life. A 1300 conversion - or even an A series - might give you more fun.

A period conversion is a Coventry Climax engine, the bigger one, not the Imp one. Good luck finding one though.

i am tempted by a 1300.......i have hs4's sitting on my bench.....just i hate the way every SU'd car ive owned has gone out of tune on a regular basis.......possibly the same with webbers.....dells seem to stay in tune though.....

i don't know ....some people could look at taking a 1500 out and fitting a 1300 as a step backwards........i may pop up canley classics tomorrow and see what they say(i live 5 minutes away).....my style of driving is
i don't drive fast(top speed wise)but i do like to rev my engines.....and everyone ive asked says the 1500 bottom end is like butter

i was looking more modern for reliability issues rather than anything else.......i guess a well built engine good ignition and carb setup would be reliable......