kenik - the really high strung race motors i have seen will often sustain an ok idle (maybe set a little higher than stock) but they will pop, fizz, backfire, stall etc when you try and apply load at low revs. when driving, this means you slip the clutch/feather the throttle etc to get them over 4000rpm or so then you can start to some decent throttle opening. when on a dyno, the operators normally just don't apply the load (or alternatively little throttle) below similar revs for the same reason

john - a friend is parting out a stock 2.7 at present. would these heads suit a 2.0 litre being built as a 'mild' race motor (eg, with ge80 or similar cams, appropriate high comp pistons etc)?

Very cool; makes a lot of sense. Seems to me an EFI system w/ wideband O2 and on the fly ignition timing might mitigate a lot of this. Perhaps even MFI to some extent (evidenced by the curve above).


I asked this same question a while back and the answer is yes; they are much better in profile to the 2.0 heads with the same stud spacing. 2.2 heads will have fewer issues with squish band than 2.7 heads due to the wider chamfer on the 2.7s, but you'll need special pistons anyway, like the custom JEs from Henry Schmidt which are specially built to adapt a 2.0 piston to the later head profile.

The problem with the 2.7L heads on a 2.0 engine is that there is a chamfer to bring the heads out to the 90mm diameter of the cylinder. If you want to use them for a 2.0, you would have to machine them down (too much to remove) or fill weld the chamfer up.

Better choice is the 2.2 or 2.4L heads. Same size vaves, just need to port them larger.