F head swap options (1 Viewer)

[Maui Cruiser]

So I have a 9/72 FJ40 with the original motor, minus the smog and air-rail stuff. No mods other than that. I have a line on a rebuilt head from a '68 F, and I want to be sure it would work. I don't know if there is some incompatibility due to open vs. closed combustion chambers (mostly cause I have no idea what this means), and flat vs. domed pistons (I can understand this concept, I'm a zoologist, not an idiot). I checked the info on the FAQ and found alot about putting a F head on a 2F block, but couldn't decipher the unique properties of the '73 motor. Fourth FJ40 I've had, first one with an F motor, all others were 2F. And as long as I'm asking, what's the deal with a vacuum retard dizzy? Can I just disconnect the line and go on mechanical advance alone? Thanks in advance.

This is what I'm considering getting:

 

[Degnol]

https://forum.ih8mud.com/40-55-series-tech/105385-2f-head.html


https://forum.ih8mud.com/40-55-series-tech/143065-head-comparisons-faq.html


From the FAQ

 

[Maui Cruiser]

Yeah, saw those posts in the FAQ and I've been re-reading them for days. The second one has to do with 3F and 3FE heads. Pretty sure that's none of my business. The other one says (quoting Mark W.):
"Pre '68 F engines used siamesed exhaust ports and a deep "bathtub" style combustion chamber. They're pretty much on their own so far as interchanginf anything.

From then until '72 the F engine used a flattop piston and a closed combustion chamber.
'73 and '74 F engines used an open combustion chamber and a very small dome on the piston."

So am I right to assume a '68 head with a closed chamber for use with flat pistons will not work with a '73 block with "a very small dome on the piston."?

Or should I just quit being stupid and swap the heads and see if stuff fits?

 

[Degnol]

I think you should be good with that head. And sorry about the no-help links I thought sure that one of them would have the JimC post about casting numbers and which ones go with which pistons/blocks. That head should have the same oiling system as your old one.

GL

Ed

 

[Maui Cruiser]

You know what, I think I'm gonna give it a try. If it doesn't work out I'll have the original head off any way and will just have to move up the rebuild date on that. It's not like I can't find other things to work on while it's out of commision.

Ed, thanks for your help. I'll go look for that JimC post on the casting #'s. Might still be interesting.

 

[71cruiser71]

i put a 72 head on a early - 68 motor. and it works fine. this might help your decision.

 

[grant5127]

color coordinated

Whats up with the red intake valve stem seals?

 

[HoboFire]

Whats up with the red intake valve stem seals?

I wanted some color in my engine so I told em to jazz it up a bit. Actually that's just what the shop put in there...

 

[Maui Cruiser]

Glad to see you're on MUD. I'll be in touch and let you know if I can get up to Spokane on Friday.

Dave.