I notice that on several types of heads, like Edelbrock and GM Fast Burn, the intake and or exhaust ports are raised by .100 or .200 inches.

I was wondering if this causes problems with the fit of intake manifolds or exhaust manifolds/headers.

Also, which gives better clearance around the headers/manifolds, straight spark plug style heads or angled plug heads?

Thanks!

 

Intakes, yes, it's definitely an issue; headers, usually not, because the headers don't match to the head port openings the way intakes do.

Spark plug fit depends on the particular headers; specifically things like how close any tubes that run parallel to the head are, which direction do they exit as the leave the heads (more straight out, up, or down); what size the tubes are; etc. In general angle plugs and headers go together better than straight plugs and headers, but not always. There are certain head/header combos with angle plugs that absolutely don't work.

 

Cool, thanks for the info!

 

I have a set of GM FastBurns waiting to go on a 409 project (400 bored .040) and I have test-fit a set of 1-3/4" SLPs on them (the valves were out of the heads).

The FastBurn exhaust port is considerably larger than the upper opening of the header at the flange. I have thought about "porting" the header flanges but the potential problems of the thin sealing area has me searching for a better solution.

The headers physically bolt to the FastBurns but the blockage would cost some horsepower.

jms

 

Would it be possible to elongate the header bolt holes vertically, so that you can move the entire header upwards to match the ports? Or are the ports just a different size/shape?

 

People do that kind of thing all the time. You're limited only by chassis clearance and stuff of that sort; in the particular case of SLPs, I'd be concerned about the Y-pipe hitting the oil pan. Although, it would be a good idea, to put some sort of spacer something in the bolt hole if you do that, so that the headers don't slip down during or after installation. The shape of the ports doesn't really matter as long as you can get a gasket to seal.

It's alot easier to describe a 400, regardless of the maintenance required on the block casing, as simply a 400; and leave it at that. Those extra couple of inches don't really matter. If I were doing it, I would describe it as being a 400 project.

 

It's alot easier to describe a 400, regardless of the maintenance required on the block casing, as simply a 400; and leave it at that. Those extra couple of inches don't really matter. If I were doing it, I would describe it as being a 400 project. [/B][/QUOTE]

I understand where you are coming from on the above quote, however I will describe it (one of my projects) as I see fit when I feel it is appropriate.

I don't use alot of bandwidth on these boards even though my 30-plus years of racing and hi-performance experience could allow such a situation. I have seen many comments (made by many people on these boards) that I could have corrected. But in the grand scheme of things it really doesn't matter that much.

RB, I'm not really upset over the comment but I feel as if a teacher was trying to correct me in order to make themselves look good in front of the principal.

And as if I was another teacher in the same school. {end of that waste of bandwidth}

Now back to the header relocation idea. I agree the idea could work but I am of the belief the y-pipe would be a problem where it passes under the oil pan.

In the case of my SLP 1-3/4" headers, my steering shaft barely clears (with the L98 in my GTA) and there may become more of a clearance problem on the #7 cylinder tube if the header was raised in relation to the steering shaft.

Then again, I've not looked at that area in a while and it could make clearance better!

jms

 

I have shorty headers and jegs aluminum heads with raised exhaust exits and it caused my collector/y pipe to touch the oil pan and cause fitment issues. I'm going to need to take the setup to an exhaust guy and get it straightened out.

 

Nothing like resurrecting a 15 year old thread. Nice to know we have a very old database.

 

Lol just saw the 2004 date on the last post... :Undead: