Have a look at simple things like.
Is the timing set properly & is it getting full advance the timing mark should move to about 20 degrees with the vac advance disconected & vac hose blocked.
The exhaust could be restricting it.
If the exhaust is old it could be a bit blocked.
Have they used an A12 carby on the A15?
Also is the vac advance conected if it is check that it is working buy checking if there is vac getting to it then take off the distributor cap conect a peice of hose to it & suck on it you will see the base plate in the distributor move.These are some simple thing to check first before spending money.
Also if it was a second hand motor do a compression test replace the spark plugs if they wearnt already changed whenyou did the job. And it wouldnt hurt to check the tappets.

A simalar topic came up about 2-3 months ago. Go back through the main forum & read those posts im sure that will answer your questions. There is a great thread from feral is a great read.
To answer your question it should give you a good power gain providing you do other things like bood carb(s) electronic ignition ect. It sound easy

Put a master gauge on the motor & check how much oil pressure it realy has. The pick up could be a bit blocked. How long since it has had an oil & filter change? Try puting an oil filter off a 2000 modle 4 cylinder camry (Z386) but get a genuine one from toyota. They screw right on & have good flow. I have done this in the past on all sorts of engines & it works good. Hope this info is helpful

Hey muke the annoying noise from the engine bay was the auxillary venturies in the carbs rattling around cos the springs that hold them is where non existant. I think the guy you mentioned that you had tune it needs a lesson in webers. Also the LHF gaurd is loose & squeeking at idle. Its all good just a bit of TLC she will be all good again.

Will see what happens will bring mukes old sedan after i fix everthing on it like two broken engine mounts & the gear box from falling out. I should beable to make it. It might run a 16 second but its all fun running a fast time is an added bonus just means more dattos there.

I think my 69 kb10 still has the origanal clarion radio but it has FM. Would that still be origanal. It looks origanal.

When dodgeman said about optional extra on heaters made me remember my old man telling about fitting seat belts as optional extras thats going back years

Have you ever heard the saying. Pushing #### Up Hill. Cos thats what you are doing by not to pulingl the motor out. MLS has the best way to hold the cam followers in. But if you have to pull the sump off you have to undo the engine mounts so you may as well undo the dozen or so other things & pull the motor out. If you havent got the equptment to do that you can hire engine cranes or get some mates to help lift it out with a pole & chain & if you havent got a engine stand sit the motor on a couple of tyres & get a mate to hold it while you put the cam in. Its not hard man.

Can you tell us what you did to fix it. Or is it one of those things where you dont know what you did but it works now
Well done

I am running a bosch elec dizzy with a gt40 coil works great

Suburu made a three cylinder modle called a Sherpa the japs may have supercharged for japan. Thats the only modle i think it could be off. But i could be wrong.