Is it possible to swap a siamese head (early to 67) to a non-siamese head (68 and later)?

[waltermayorga]

Hi all,

Hopefully there is someone here that can help me with a dumb question. By looking at the early to 67 FJ40 engine specs, looks like all them came with siamese ports head (different intake and manifold too), and I wonder if is just the ports in the head or if there is a difference in the crankshaft and engine block that prevents from swapping the head to a non-siamese/individual ports (68 and later cylinder heads, like the 60030, 60031, etc).

Thanks in advance

 

[Oceandog]

Hi all,

Hopefully there is someone here that can help me with a dumb question. By looking at the early to 67 FJ40 engine specs, looks like all them came with siamese ports head (different intake and manifold too), and I wonder if is just the ports in the head or if there is a difference in the crankshaft and engine block that prevents from swapping the head to a non-siamese/individual ports (68 and later cylinder heads, like the 60030, 60031, etc).

Thanks in advance

Hello Walter,
Did you have any luck finding out if you can swap the heads? I have a 66 fj40 that needs a new exhaust manifold and was hoping to swap to a newer head and headers at the same time.
Thanks

 

[Dirt Bomb]

I used to run a 69 head on a 65 block and don't recall any problems.
breathed better at higher rpms and less burnt valves.

 

[Living in the Past]

9/73 the oiling system changed. Instead a copper tube to rocker assembly it was internal inside the block, head then into one of the bases on the rocker assembly.

 

[waltermayorga]

Haven't tried yet, but according to previous comments, looks like it is possible to have a head swap if you use something previous to 9/73?

 

[Living in the Past]

Also the push rods changed between the F135 and F145. Toyota dropping anything before 3/69 makes it difficult to figure what works with what. Before I did anything I would at least buy a head gasket for the 3/69-12/72 part number 11115-6003. Then verified all the passages line up. Something changed 12/72-9/73 but that part supercedes the previous number.

 

[waltermayorga]

Also the push rods changed between the F135 and F145. Toyota dropping anything before 3/69 makes it difficult to figure what works with what. Before I did anything I would at least buy a head gasket for the 3/69-12/72 part number 11115-6003. Then verified all the passages line up. Something changed 12/72-9/73 but that part supercedes the previous number.

Good suggestion. I have a cylinder head out of a 71, I will try with that head gasket and see how it aligns

 

[MiSFiTiSM]

Good suggestion. I have a cylinder head out of a 71, I will try with that head gasket and see how it aligns

How did this end up working out for you? I am looking for new headers but can’t find any 3-1 Siamese port headers, so if I can upgrade the head to ‘68-‘71 I should be able to get new headers as well.

Thanks