the weight advantage of the sigma 1.6 over the pig iron pinto is a no brainer, same power give or take after its been tuned with carbs/ITB`s etc in my oppinion,

or going to that extent then a 1700 pump lump is same job to fit, plenty plenty RWD stuff on the market as the kit car brigade LOVE these engines, checp, readily available and VERY VERY tuneable!

Sean.