I think that only 1.7 with mech tappets had lower compressionduw to different design on the heads , similar to 1500 . Also there is deiference on the piston heads and thats why it is difficult to swap heads .....
If anything, with the late TI QV 1500 105HP heads the 1700 would have compression that went through the roof as those heads are flat, not dished like the hydro 1700 heads. The difference is about 15cc. YOu would need pistons with a deep dish to compensate. I'm in the process of buying a mech tappet (but very worn) 1700 engine just to compare all the differences, not because I need one. I have a pair of ported 1.5 105hp heads, they all have the same 40mm inlet valves as the 1700s, and these have ports 36mm and manifolds expanding to 40 mm for the carbs and i will build a strong 1700 with them with forged pistons, only need to calculate piston height for the right compression, aim is about 10.5:1.
For a supercharged or turbo 16v you could use a 1500 (or 1350) crank and have a 1600 with lower compression, the blower will make up for the slight loss of displacement.
'08 GT 3.2, Sud '82 QO, '76 Ti, '75 L, Montecarlo, 308.
Last edited by bert308; 03-06-14 at 20:15.