I have a 1200 ute and im looking at doing a L series swap. Im using a L series block for a reason. I was thinking of doing a L20b with ka24e head, raising compression some how, mild cam and maybe twin cv type carbys or maybe quad throttle. What are people's opinion with mixing ka and L series also stroke vs revs ect? Others say I should go L16/18 because of higher revs. Im a little undecided

I well setup L20 head will flow more then a ka head. But the beauty with the ka head is the cross flow design so you can play easier with manifolds etc.

Going a small capacity engine for rev happiness, vs a larger capacity engine for stroke and hp are always going to be two different wants. You have to decide what you prefer. 8+ grand of noise or 6.5 grand of torque. What sort of gearbox will you be running, final diff ratios etc. Deciding on a whole package affair will help you gain more insight for what engine requirements you'll be needing.

For a small vehicle a spritely small capacity engine always sounds good. Adapt your quad throttle body or carby setup, good exhaust and reap in the angry noise that's produced. If you're into skids and some silliness then banging a stout l20 in there will be a good starting point. Whack the ka head on, induction, exhaust. Then see where it takes you.

Up to you really. What do YOU want out of it?

I cant remember what a 1200 utes final ratio is but I know my 1000 ute was 4.11 & 4.375 which I liked. I wanted to use a stanza dogleg stumpy box so the misses found it to complicated to drive lol. I like revs! Im thinking of a L20b bottom end or L18 but I have to also look into chain and timing cover for the shorter L18 block. I kno the L20b shares stuff with the z20 to mate the ka head so im hoping the z18 will match the L18. This is going to be for a little street rod

I doubt a full works L20 head would ever outflow a KA24DE head.
Les Collins would be surprised with that

KA head has the reputation for being the best flowing head you can put on a L series bottom end, even better than the nissan LZ twin cam heads

Don't kid yourself though, it is an expensive and challenging option, but well worth it if you have the time/money/ability

The other issue is getting bores big enough to clear the valves on a KA24 as the KA24 runs a 89mm bore

Plenty of info around if you search.

Would anyone know where you can get one of the 16valve ka heads?

Yep. Any wrecker with the last of the Bluebirds. The front wheel drive ones. The KA24DE engines were also in some Navaras. The Bluebird heads are a lot cheaper and easier to find, but beware- a lot of these heads have been overheated which makes the alloy too soft to use again. I had to get 3 before I got a good one.

Also some Fords have them on the rebadged Bluebirds
A relatively stock ka24de head with a sleeved 89mmL16 block done by Baz for a lightweight setup
or at worst a thick L18W or Z22 block with L18 or L20b crank respectibly will do nicely

Its not that much $$$ compared to forking out for a fully worked L20b head

Actually it's (relatively) easy and cheap to do it with a bored L20B or Z20 block. It's possible to bore them to 89mm (mine has been reliable at that for years) and they're plentiful, strong and can rev hard. Using the taller L or Z block makes it much easier to adapt the timing covers to join and simplifies the solution to the timing chain guide issue. If you're in Melbourne PM me and I can show it to you in the metal. Whatever you do there's a fair bit of custom work and not just on the long motor. I love the idea of a CV or flatslide carbied LKA21DE but manifolds (both inlet & exhaust) need to be made and you need to consider stuff like how much room is in your engine bay and what slant the motor needs to sit at- which dictates your sump, engine mounts and gearbox bellhousing. Plus you need to supply spark and there are a couple of options there, too, but no easy bolt-ins. It can certainly be done, but if it was easy everybody would already have one.

time and perseverance is the key and doing one of these hybrids is a separate challenge to doing up a body

You're correct in thinking the z and l timing covers fit either the z or l series blocks. But for that bolt on ability, only the ka-e head bolts onto a z or l block with the z series timing covers. When bolting on a ka-de head you need to graft the ka and z timing covers together. Can be done, but requires some effort.

The comment regarding the bore to valve clearance. Big bored or eyebrowed block would work too. But its a bandaid fix to a problem.

U13 bluebirds are where you source the fwd ka-de heads. Or out of the update d22 navara's which is the ideal choice being they're rwd configuration.