Topic: cb750 head and cylinder interchangability

[HB-1fan]

To what extent can heads and cylinders be interchanged for all sohc 750's. Is there deck height differences, different rod lengths, valve train differences(other than cam specs). Can a k2 head be put on a k7 engine that is stock. Would be interested in some cross-reference material on these issues.

Thanks,
Rick

[dusterdude]

from what i understand all the k heads are the same.

[StevieMac]

from what i understand all the k heads are the same.

That's not my understanding.  I've swapped a '78 750K head for a '72 and was told I needed to swap the pistons and cylinders as well.  I think later year valves will contact the pistons of earlier motors. 

I'm sure someone will pipe in with all the particulars though. 

[dusterdude]

very possible stevie,i do know the f engine stuff is different

[Jerry Rxman Griffin aka MuthaF'er]

You should be able to bolt the K2 head to the K7. Your K7 cam is hotter too so I'd use that and it's cam towers. This is much simplier swap than if you were to use a 77 F2 or a 78 F3 head on any of the other 750s in which case you would have to swap the entire top end. The 77 K7 and the 78 K8 head is the same as the 75 F0 and 76 F1. These are a factory hemi style somewhat similar to a head Hondaman is building in a post. You might lose a small amount of compression and have to rejet. Your K7 head and pistons provide a compression ratio of 9.2 : 1 vs 9.0 in the earlier K's.