Spark plug angle/location differences?
 

I am going to be putting a stroked 400 into a '63 Tempest with an aftermarket front suspension crossmember and steering rack that will make clearance very tight for headers and steering linkage. As such, I have to design and fabricate my own headers and steering linkage.

I currently have the block mocked in place with a set of 6X heads on it just to get an idea of clearances. I hope to fabricate the steering linkage and headers now with this mock-up in place. However, when the engine is built (finances dictate this will happen later this year, at the earliest), it will have a set of Edelbrock heads on it with a round exhaust port.

I have found that I can mount the round port exhaust header flanges to the D-port head by using the outermost two flange bolts. I'm hoping the D-port head with the round port flange on it will serve as an acceptable mock-up to build the headers.

So the questions...

In short, will I be asking for fitment problems later when I swap heads if I fabricate the round port headers by bolting the round port exhaust flange to the D-port head? Specifically, are the spark plug angles and locations the same on the 6X head as they will be on the Edelbrock round port head? Will the flange location be different between the two heads (e.g., the angle that the flange points off of the engine, or its height/lateral location)?

I want to get this part of the project done, but don't want to fab the headers and then have them interfere with the plugs, or run into the steering linkage or frame when I have the round port heads on there.

Any thoughts are much appreciated.

I don't think it will be a problem.
The plugs point away from the tubes.

Not sure how the middle of the flange will be with no bolts in it though when welding?
(may warp)

:)

Thanks for the thoughts, John. Good point on potential warping. At this point I was just planning on getting the pieces cut and bent and tacked together to see if this plan is going to work... then welding it all up later.

I probably should have named this thread something different... I had spark plug location on the brain because I was considering looping the #1 primary tube up and running it back just above the exhaust ports and dropping it back down after the third port on that side. Like I said, it is going to be a tight fit to make the steering linkage work! Now, I think I can probably avoid doing this, but it is going to take some clever routing of tubes.

So, just checking in to see if anyone else has any thoughts specifically on the location of the exhaust flange relative to the deck. I've spoken with a couple of folks who have said the relative angles between the deck surface and exhaust surface going from a 6X to Edelbrock round port is the same, but I'm always happy to have more data points. Also any thoughts on whether, even with the same angle, the exhaust port is even slightly different in location side-to-side, etc.