The Importance of correct flanges...

[Y-TRY]

I mentioned in another thread that I had an issue with mis-matched flanges. Here's what I speak of.

I bought a set of headers made for another engine. At the time I didnt have the choice of changing head flanges. Besides that, I went with 1 5/8 tubes and large AFR ports. Well, here's the result:



As you can see by the soot and burn pattern, the flanges don't match very well. Conveniently, though, the heads burned a neat stencil into the flanges showing me exactly where they are off. Gee, I wonder if this is costing any power on my turbo car? (just kidding).

I am going to try to band-aid it and blend-in the corners and side edges using the marks left by the exhaust. It still can't be exact because the actual ports are spaced differently and larger than the primaries. You can even see the hot/cold spots.

It's one of those "shoulda had a V8" head knocking moment. But I'll figure it out and show you some "after" pictures.

[Rick Dorion]

Ah, yes. I feel your pain. The feedback will be greatly appreciated. I barely have a match with my ProToplines and an old set of 1 3/4 Hedman's. The square head port is a pain. Thanks for the pic.

[Y-TRY]

In speaking with a couple people, including Kook's, the basic opinion is that the port being masked like this has a negligable effect on power, probably less than 5 hp, as long as the top of the port isn't covered. The majority of the exhaust is racing out the top edge of the port anyway, as the story goes. The tops of my ports are actually pretty perfectly lined up.

Since this is a street car the power loss is less of an issue than a competition vehicle. None of the solutions really justify the means it takes to fix it. I could buy another set of $1800 headers, but that would be the most expensive 5hp I've ever seen. So they'll go back on as-is. If I start noticing extra wear or stress from the flanges heating up or something I'll deal with it then.

So much for all that porting on the heads.

Mistake made by me..... lesson learned by all....... I'm here for ya, man.