the 1.3 and the 1.6 heads will interchange....no problem......
i find my self leaning twoards the use of 1.6 heads.....
they just seem to make more power on either motor .....
if a 1.3 head is all ya got by all means run what ya brung aint no sin in that.......
my first 1.6 head came from a 1.6 with a shattered lower end.......i worked out fine.......
the 1.3 head will parts will bolt up to the 1.6 head.....
intake exaust and disty.....
side note on the disty.......if you have fi i beleive the 1.6 disty housing and disty will work fine......
if you have a carb model then just take the the whole disty assy off of the head and move to the 1.6 head ....
it bolts up
