22r block with a 21r head ??

[sumfancyname]

just wondering if itl all work.if not wat wld i need to do to make it work
thanx zac

[o_man_ra23]

Should work. The seppos have been putting 20R heads on 22R's for a while. Wondering what the advantage is?? 22R head allows for the fitment of EFI or carby (see Hilux/Landcruiser 22Rs), where 21R restricts you to carby or a whole bunch of work to fit EFI.

You will need to check the combustion chamber shape, as differences here may require custom pistons, though I am fairly sure that the 21R and 22R combustion chambers are similar.

So why do you want to put a 21R head on a 22R??

[sumfancyname]

well my mate wants to no if i will do it for him because he wants to build ke70 with a 22/21r in it and he dsnt want efi and i am a realy big fan of the R's as i have a 21r with 155hp and i said ive always wanted to try a 21r head on 22r because we all no how crap 22r heads are(revving)and i thought itd be fun to do so yeah lol

[o_man_ra23]

22Rs don't rev because they have a long stroke. Not because the head won't rev. 21R head is pretty crap really, so no real improvement for a lot of effort. If you want to stay carby, just get a Hilux or Landcruiser 22R, put a decent cam in, and look for some higher compression pistons. It will be almost impossible to get a 22R bottom end to really scream with revs.

[sumfancyname]

well according to this its the head (cam duration.but a little to do with stroke)
http://www.toymods.org.au/forums/showthread.php?t=61438

[o_man_ra23]

Just read through that thread. The items which prevent the 22R from revving are:
1. Swirl port design
2. Cam profile
3. Stroke
4. Primitive EFI

The solutions to all of these are:
1. Port the head - surely you would do this for a race engine anyway??
2. New cam with improved grind - stock cams are junk for race engines.
3. Use longer gearing and enjoy the longevity of a slightly lower revving engine.
4. Aftermarket EFI - you mentioned using Methanol, well that pretty much makes the stock EFI useless even if you weren't concerned about revs.

So if you are building a race engine as you specify, then you will pretty much overcome all the obstacles of the 22R head through a matter of course anyway, and it is only the stroke that would limit you.