Maxrs
Have you done or seen a Sigma head fitted to the Pinto ??
Did these ever come out in a twin cam config ??
 

If you were going to muck around fitting a different head you'll want to make it worth the time and effort.  I wouldn't spend time with anything 2 valve/cylinder for a start.  There is nothing wrong with the standard head if its done right if you're planning on that, and the time and effort to put another similar head on would be a complete waste of time in my opinion.
 
There is a Volvo 16 valve head that I beleive can be made fit, at a cost. 
 
As stated earlier in the topic a Cosworth engine is available pretty cheap at the moment, so thats probably the best option bang for buck.
 
Cheers
Woz
 
 

Sorry for a bit off topic but a mate at work fitted a BMW twin cam motorcycle head to his 1275 mni bottom end in his race car
So if you have the skills and resources there may be other options but for the money you're talking to modify and fit a different head I think there are more viable alternatives with greater potential.
Duratec
Zetec
BP1800
SR20
CA18

Wozzah

There is a Volvo 16 valve head that I beleive can be made fit, at a cost. 

Unfortunately the volvo head won't fit the pinto found in escorts etc. but it is possible to put one on the american 'lima' engine which is found in mustangs, rangers etc. in america

Ah yeah thanks guys, i plan to just put the pinto in there, with a some work done, and get it registered, while everything is looking normal-ish, then after that, work on going silly. would love to stick a cossie in there, that would be fun! but as for sr20 ca18 i would much prefer to stay all ford, well for this project anyways! got a couple to have some fun with once this project is finally finished!

If you were going to all that trouble.. why stop with a pinto?
(skip to 2min30sec where the car actually is)
http://www.youtube.com/wa...eature=player_embedded
 
Such a shame they spin the opposite direction to most engines.. id be installing one in my mk1 in a heartbeat!!!

I have a few pintos laying around in the shed, and i'd like to put that in first for simple registration reasons, as i want to run it on full reg, and then once it is registered i will heavily modify it and or conversion that i can slowly get done. call me old fashioned but in my opinion i would prefer to keep this one amuch ford as i can.

Would only do it if it was a decent twin cam and for the challenge.......