3T Pistons in 2T Block

[sneaky pete]

You say the big port head is not that good. That is interesting 'cause man they are scarce like hens teeth! Is that because they are inclined to crack between the valves ? Or ARE YOU SAYING THERE IS A PERFORMANCE advantage in using a small port (maybe lower down in the rev range?). We run from about 3000 in the corner to just under 6500 RPM at the end of the straight (average about 25 laps per heat). They are pretty strict on the fact that everything must be as made by the manufacturer. But obviously you may recondition. So porting is out! Whereas if the manufacturer made the motor with a big port head is ok provided it is still untouched / not ported (repaired cracks etc is ok). We run a 38 Weber (recntly introduced , largest allowed) with an adapter onto a standard inlet manifold (must be std manifold) and an exhaust branch (recently introduced rule)
I am interested what comments there are on the big port head. Also any point in just running a big port inlet manifold if using the smaller port head which may not even be matched / machined to suit the manifold ?

[J-M kujala]

Ok. If porting is not allowed, then its way to go with big port head. And with early 5 finger intake.

Here is not any racing class where is illegal to port heads, so big ports are not get any extra value. (exept FIA historic rally stock car class) but there is not that many or them. And can still go with TG head.

That crack, yes they usually crack after some heat cycles enough, but have you seen never any problems ? I have not. Even with big cracks the head wont leak at anywhere. So never seen big crack Enough, to cause any pronäblems.
Even with turbo engines and with alot driving in the tracks.

[sneaky pete]

Well thanks for that info JM. Now the problem is to find that head and inlet manifold. I will start by having alook around here. Failing finding one here, I will have to look elsewhere. Anyone on the forum got one ?

[J-M kujala]

Only intake with Smaller port head match well. Some mid 70"s 2T engines got that conbination at original.

I do not remember those port sizes, but 5 finger is the biggest and intake is bigger "limiter" than head. Maybe it was 29mm diameter at STD never type intake and ~31mm 5finger. these are what i remeber, so not its possible they are not exactly correct. So long time when i measure those. Big port 2T ~33mm and never modell 31mm . Then some 29mm version have seen. 31mm is the most common head.

I got one early intake but shipping will be expensive as hell...

[sneaky pete]

What would you want for it ? My daughter is going over maybe I can convince her !!!! Let me know, thanks.

[J-M kujala]

Basicly this is not for sale, wanted or like that topic, sent PM if needed.

See my location

<-- im not from Aussie. a lot, up to north, from youre location.

[jb_22]

I have two 3Ts sitting here, one with EGR type head, and one without - could one of those be an "early type" head? they also have intake mannys too I could check for differences?

[J-M kujala]

3T never got big port head, all 2T:s 70-72 and some small amount of later modell without emission rules. 5 finger intake up to -75 when there is no emission law in the engine. C type engines never got big port head, and head come always with 5 finger intake or with double aisan carburators.

Heads usually found from early te27 corolla (USA) -->72 , Ta12 Carina 70-72, TA22 celica 70-72.