I'm trying to get my manifold ports to match up with the dart pro 1 heads and I ran into some difficulty.

First, the ports of the dart's are not completly rectangular and secondly, there seems to be a core shift in the intake i'm intending to use. It's a pretty special intake, so i don't want to discard it due to inavailability.

The problem lies in the fact that the port of the head is higher. When i modify the manifold it leaves only about 5 -7 mm of material on top of the manifold port for the gasket to rise on.

Second, the ports on the manifold are to wide, mainly towards the pushrod area. This can be ported to size as the difference is in the order of 2-3mm and there is still enough room for the gasket left. However on port 5-7 i have a real problem. The pushrod wall of number 7 is about 7 mm more to the back of the engine and the common wall seems only to cover half of the common wall on the head.

Did someone encounter such a problem before and if so, how did you solve it.

I was thinking on welding in material but i'm a bit afraid of warping the intake. Maybe some epoxy or Moroso A-B ?

Input greatly appreciated.

 

Epoxy is no big deal when bringing intake manifold runners down to match smaller ports, such as was done below, as long as the shape is well blended back towards the plenum.



That said...

The top of the port/runner match is pretty important, but if you have little or no room to raise the roof of the intake runner you do run into the possibility of adversely altering tapper as you approach the valve should you bring the head's intake port roof down to match by whatever method. The better are the heads, the less I'd want to mess with them.

Doesn't exactly help solve anything, I know. Just making sure you've also taken this into consideration before proceeding. And, I'd definitely talk to Dart here first.

 

Thanks for that info.

Regarding the roof of the head's ports : these are higher than the intake ports. I would have to grind the intake to get a match there. It would leave the manifold flange above the port a little on the small side, like 5-6 mm. Maybe only just enough to get a seal.

I will probably create a larger zone in the intact tract that more or less decreases velocity, but i don't think its going to be something i can avoid.

 

Just thinking, maybe someone like Wilson Manifolds could help you out.

 

U need to list which Dart Pro head. Which intake? Any machine work on the deck of the head or cylinder block or has the intake been milled?

But this sounds like that intake is a poor selection for those heads - at least the port style on Dart heads.
If the port on the heads is higher then the intake could have been machined/milled and the only good fix is adding material to the floor of the intake. Do the bolt holes line up? Don't take metal away from the head port, especially the floor!

U posted the manifolds are too wide towards the pushrod area - this makes no sense. I think u mean to say the manifold is too wide on the same side as the pushrods in the head (the pushrods are in the head). Again u plan to take metal from the head ports and a bad idea. Port design is critical to good flow, velocity, and flow profile to prevent turbulent flow patterns. U will undo what Dart spent great effort to produce.

Intakes are cheap and that's a good thing as it allows us to try several for best performance for fewer $$$. I don't know why this one is soo special. If a special intake i would start with a sacrificial intake for fit and testing. If u really need a corvette numbers aluminum intake let me know as i have a few OE from the late '70s.

Hope this helps more than it hurts,
cardo0

 

Measuring a fel pro gasket i have it is 6 mm deep at the top 7mm at the bottom.. Its one of the bigger ones a 1206.

 

It's an ITB manifold complete with matching throttle bodies.

I fiddled with it some more. I got it lined up pretty well. I will have to do some porting both on the heads and the manifold.

I know that Dart did some pretty good out of the box porting on these PRO 1 heads, but the port design doesn't look so well if you ask me. It seems as if it was meant to be ported to a manifold.

Anyway, if i leave the manifold ports bigger than the ports in the head, airflow will suffer more than when i do file the ports on the heads.

I will probably have to add epoxy to the manifold on the top of the ports (outside of the runner) to get a large enough surface for the gasket. As such this is not a problem since it is outside of the manifold.

However, i will probably have to widen the flange of the head on the outside.

 

So if your intake manifold runner is a tad wider then the head runner, air flow will suffer. A blockage up top by the manifold you describe will hurt things need to fix that. Leave the head runner alone.

 

I don't know anyone else here running a sophisticated set up as that. U are trying to utilize mostly full race parts on to a street car from what i can tell. That is really a team effort like for racing campaigns that could take a lot development - that is out of my league.

All i can say is i wish u good luck.
cardo0