Unique Cylinder Head Question

[DustyDave]

I have a 1978 Fiat Spider that I have been restoring the past 9 months. This is my first restoration of any vehicle, though have wanted to do a restoration for the last 30 years. The engine was seized up so I got lucky and found and bought a partially finished short block and partially finished head. I got both back together, mounted the head, then found something interesting about the head. When I went to mount the manifolds, I found that the head had an extra port that went through the head on the front side of the engine from IM to EM side. My manifolds (from original engine) did not mate up to this port, though it fit the rest of the head fine. I ran a camera scope through the hole, and indeed it just goes from the IM side to the EM side, and does not open to any coolant, oil, air, or exhaust passages within the head. So I assume using the head is fine, this port will just be open on both ends. On the old head, the area where the port is in the head has no material, so looks like the head casting on the new head added extra material to allow this passage. They are both casted as Fiat heads, with original head cast with FF 134 AS 6C 4372291 S62 and reman'd head with extra port was cast with 132 AC 2C 4406111 S62. Internet search indicated it was a compatible head with my car. In any case, I decided there were no real concerns and to use the head anyway.

So I was just wondering if anyone has seen this before, and has any information / advice on the impact of using this different head? I am curious if anyone knows what the extra passages was used for on other years of spiders, or if maybe the head is shared with other Fiats or Lancia's that make use of this port?

Thanks, David

[redcars]

I believe that is an EGR port .

[wetminkey]

A simple Exhaust Gas Recirculation port that traverses the front of the head. My '79 has an extra tube from the exhaust manifold that attaches to the EGR port. The gases pass through the port, and out the other side, into a dual plane manifold that recirculates them into the intake gases. It serves no other purpose.
I have replaced my 1979 dual plane manifold with a single plane manifold, so I have blocked off the EGR port on the intake side. It is still attached on the exhaust side,...(pics in "ADHA to DFEV" thread in Performance section,...)
Enjoy your restored car!
Todd.

[DustyDave]

Todd,
Thanks so much for your referenced post with helpful pics. Seeing both manifolds and the older manifold with all EGR equipment makes perfect sense on now, I understand. My older setup has all that EGR equipment with external plumbing and so I see as years went by they integrated it into the head for a cleaner (pun intended) setup. Though with the external plumbing, easier to remove and disable. Thanks, as this gives me confidence in my choice to use this head on my engine with no concern of the extra ports.
Just reinstalled my engine in the spider and much work still left to do (fuel system, carb rebuild, brakes, etc.)... I am enjoying the work but anxious to get it on the road
Thanks again,
David