I need a new head for my A14, old one is soft from overheating... will an A10 head bolt on and if so are the ports and valves and combustion chambers the same sizes?
If not, will it raise the compression too much if the combustion chamber is smaller?
can the ports be ported out if they are smaller? and can the valves be swaped in if they are bigger on the A14?

the cars a KB10, has a lumpy cam and 2" exhaust system. and the old head was shaved 1.5mm, im intending to prep it for historic racing in the unmodified and sub 2.0 class, so it needs the performance, not to just run.
cheers and thanks in advance for the help

Hi 1000coupe, as far as i know the A10 head will bolt on but the water and oil ports dont match up with the ones in the block. eventually the motor will let go with no oil and water so dont do it stick with an A12 or A14 head. cheers. Adam.

can be done, not worth the effort. Get a 120y onwards A12 head and that will bolt on with increased compression suitable for all round work. A10 and early A12 heads have the oil gallery up front of head and the later A12/A14/A15 have the oil gallery in the middle(side) of head. Place your old A14 headgasket on top of A10 head to see differences.

OK, there seems to be a bit of misinformation here. This is my two-bobs worth

1. The A10 & 1200 heads will physicly bolt to the A14 block.

2. As far as I know, all the coolant passages in the heads are the same, but there may be some minor variation in shape or size.

3. Neither early or late engine had an oil feed at the front. [where did that front-feed rubbish come from] Both types feed the rocker oil up one of the center head bolts, but the internal drillings that got it there were slightly different from '74 onwards.

4. As best I can tell, you can use an early head on a late block without needing to modify the oiling for the rockers, but not the other way around. I will be using my 1200 GX head on a later A13 block without mods. Make sure that you use the correct, later-type head bolts.

5. The A10 head used round ports, while your A14 used larger oval ports & a different manifold bolt pattern [that the A10 doesn't have]

6. The valve sizes in the A10 head are 35 & 29mm, while the A14 valves are 37 & 30mm
You should have more compression with the A10 head, but it will not make up for any of the other deficiencies.

7. You can have the larger valves fitted, but you will not be able to economicly get the ports to match the A14 ones for airflow.

To summarise.
Use the A10 head, manifold & carb as an emergency, temporary, get-you-going fix if you are desperate to have a running car for a week or so untill you can get the right parts, but otherwise, it's not a good idea.
Your best bet is a good A14/15 head, & if the old one was cooked, then get your cooling system fixed before it happens again.

ok thanks, not worth doing, will wait for a good'un then.