pre-pollution heads --(Paul Clausen)

old forum · hod rodder Joined: 04 Oct 2001 Posts: 15499

I understand that some models of gemini had better breathing heads than others because of the need to strangle them to meet emissions requirements. My question is exactly when did they change to the shittier head. I had a stock 78 TD which went way better than my friends athsmatic stock (in very good nick) TF or TG, but I would have thought the main pollution changes happened b4 78.
Also are pizza front brakes a worthwhile, cheap bolt-on? I thought they'd complement a piazza rear end well.

old forum · hod rodder Joined: 04 Oct 2001 Posts: 15499

the pre-pollution heads were on TC gems only but i don't know when they came out, about 76 i think

old forum · hod rodder Joined: 04 Oct 2001 Posts: 15499

I think its actually the emission control gear on the exhaust manifold that strangles them. I had the original head on my 77 TC till I cracked it. Then I got a reconditioned head off a newer model which has extra holes in the tops of the exhaust ports where emission control crap bolted in. I just blocked them off with some old plugs from a VN Commodore and it goes as good as it ever did.

old forum · hod rodder Joined: 04 Oct 2001 Posts: 15499

The TX TC and as far as I know, TD all had the good heads. ie. Big ports, big inlet valves and small combustion chambers. The TX model (not sure about TC) also had a better flowing exhast manifold. The TE model got exhaust gas recirculation EGR whilst the later models had this plus an air pump. Real good stuff.