95 heads vs 96+ heads

[GTP_MuNkY]

OK, so it looks like now I'm going to have the heads off my engine along with the intake assembly, so I'm considering going to the 96 heads if I can find a decent set. I also plan on attempting to get the Ford SOHC springs for it and the shims from the 60*v6 store, along with a good P&P job.
Aside from the size and shape of the exhaust ports what difference is there? I tried doing a search for 96 heads but it came up with 1400 and some odd results on 30 pages.
Also, when going to the 96 heads should I also go to the 96 upper and lower intakes? I know the upper intake has a separate peice TB, but is the lower intake really neccessary?
If anyone could link me to a thread on possible performance advantages or differences in the heads it would be greatly apprieciated.
Thanx
Jamie

[timg]

Here are some pictures.

Tim

[95black34]

How much better is the 96+ heads?

[donk_316]

alot.

[5speedz34]

alot.

Has this been determined? I thought the only real improvement is in the exhaust port(flows better). Wouldn't a ported head flow as well if not better?

[timg]

The combustion chamber shape is better also. It should result in better emissions, more power, and more detonation resistance.

Tim

[SappySE107]

Im not convinced of the 96/97 heads superiority yet.

[93GTP]

Does anyone know what the difference in volume is in the combustion chambers of the 96-97 heads versus the 91-95's? I know supposedly they are smaller but does anyone know the volumes of each? Or does anyone have access to a set to cc them? I'm trying to figure out what compression ratio I would be at if I used a set of 96-97 heads with the 91-93 standard pistons. I'm thinking about swapping these heads onto the 92 Z34 engine I'm rebuilding.

For that matter I would like to verify that I can swap to the 96-97 heads without any problems?

[SappySE107]

91-95 are 54cc and 96-97 are 51.5cc

[93GTP]

Thanks Ben, once again you have the answers. So I would get a small bump in compression if I swap to the 96-97 heads, a little over 9.8:1 with the standard pistons I believe. Has anyone swapped to these heads on a pre-96 engine and kept the original cam carriers and intakes? I want to make sure they would swap onto my 92 engine without presenting any problems (does everything bolt up the same below and above the heads)? Also has anyone ever gotten flow numbers comparing the 2 designs?