Engine configuration is stock with D-Jet except 2056cc and Elgin 330-1 cam.

I bought a pair of rebuilt 2.0 stock heads (seller says rebuilt by Brothers I think in Riverside) and only one head has a vent tube.

I've read Len's article on not venting the heads. So here are my questions:

1) Should I have a machinist install a vent tube in the other head even if I don't use it
and just plug it?

2) Is anyone running a stock engine with no head vents or head vents plugged? If so, any difference in performance. Gets back to question 1, if I'm not going to use it I'd rather not drill and plug a hole.

3) If I use the heads as is, does it matter which side I put the vented head (even if it's plugged)?

4) Is there an application where only one head vent tube is used?

Thanks

Not sure about all your questions, but the passenger side head (3-4) is drilled and tapped for the CHT sensor. (I only have a little experience with 1.7 heads. Not sure if all 2L heads are drilled or not. Just make sure you can install a CHT sensor on the correct side.)

I think I would have a machinist install a head vent while the head is off the engine. Even if you just plug it, it will be a lot harder after the engine is together.

I am running 2056 with new AA Piston 2.0 heads setup by Len and have both vents plugged Seems to be running fine. Less mess in the engine bay.

75,76 models had no head vents. Drilling the unvented head then plugging it, sounds a little silly. Just leave it.

I don't think the difference between vented and non-vented is significant. So I'd say feel free to go either way. With the following overriding caveat: carbs and ITB do not benefit from head vents.

I would also recommend against only using one. Either vent both, or plug both.


I suspect the 75/76 didn't have head vents because they would disrupt the L-Jet fuel injection.

Did 75/75 have an ljet motor?
I thought (could be wrong) that only the 2.0 liter djet was all they sold???
I think in that instance 75-76 they were struggling with emissions so the air injection idea, along with air pumps and a few other terrible ideas landed on those later years.

I have run both with and without vents and under normal street driving I think the best way is no vent, no mess, and less oil mist in the engine bay.

Higher revving , custom built racing motors....YMMV

I remember a set of head that came back from a shop and the pressed in vent tube was loose.
Without a hose with clamp on the outside, there is nothing to ensure the tube won’t fall into the valve train...