What's an "easy" visual distinction for a tii exha

[Grover]

I'm trying to figure out if I have a tii or "regular" exhaust manifold. What's an easy way to distinguish them?

[tjones02]

Tii exhaust manifolds are easialy spotted by their lack of Smog ports at all, none, nada, zilch, nicht. Earlier ones don't even have the bosses for smog ports, while the new ones avaliable these days have undrilled bosses for the smog equipment of other US spec 2002s.

[jerry]

i'm at a loss as to all the fuss about a tii manifold. there's been a fair bit of discussion about em, with photo reference provided on the my2002tii site as well. as stated above the only difference is the drilled out bosses for the smog stuff. other than that, if you can find a regular one and merely remove the exhaust probes and block off the holes, i'd argue that you've just configured a tii manifold.

i have both types lying around and they are essentially the same. However, having just typed all this, i have indeed noted on my spare 74tii engine, the exhaust manifold does appear slightly, and i mean, slightly, larger than the other tii manifold i have (too bad it has a large crack at the No.3 port).

[brad_c-ville_VA]

try this thread i started a while back for just this reason:

tii vs. non-tii exhaust manifolds

[tjones02]

Korman Autoworks in conjunction with the Roundel did an article in the early '80s of a comparison test of an early '02 air injection smog manifold, a TII manifold and a few sizes of Stahl headers. The flow and dyno tests proved that the tii manifold made good power and better torque until around 150hp. From 150hp and up the headers larger tubes and higher flow finally came out on top. That the TII manifold was stock and not ported was very impressive. The stock '02 air injection manifold was a distant dismal last.

Maybe Mike Self can help us use a scan of the Roundel article here on the FAQ.

The '74 and 49 state '76 manifolds are a second best next to one from a Tii due to a lack of air injection tubes etc..

The original 2000ti, 2000tilux, 2000tii, 2002ti and 2002tii exhaust manifolds appeared to have larger internal ports along with a look of a cast iron shorty header when compared to other much heavier US Smog 2002 "air injection" manifolds, the latter US smog manifolds looked much closer to the tii ones but there were still subtle differences between them.

[Jim_75Sahara]

My '75 had a standard manifold w/smog ports sealed off in an improvised fashion by some p.o. (All my smog equipt. was long gone. ) A couple weeks into ownership, I was going 80 MPH when one of the plugged ports blew out with a huge bang and smoke followed. I was sure the engine was blown for a few seconds. Then I realized there was no change in power or RPM's or even sound. I guessed that it was the exhaust manifold, which indeed it was. I have noticed a little more power with the tii manifold and also a much more pleasant note to the engine at high RPM's. Plus, I don't need to wait for the next smog port to blow out.