[dana44]

73_duster, on Jun 29 2008, 02:31 AM, said:

I am planning on maybe port matching the intake manifold to the heads. I have a pair of fully ported J heads from the original 340 dodge, and a edelbrock performer rpm airgap intake manifold. Hears the slightly confusing part to explain... The INSIDE walls of the intake ports on the heads are flat and have no curve in the beginning. The OUTSIDE of the intake port walls on the heads start curving to the INSIDE of the port. I have already drawn a guide on the intake manifold of where i can grind down, but the question is, would it be good to grind down as much as i can on the intake manifold runners to excactly match the head ports, or should i just grind down the side of the manifold runners that would line up with the Inside walls of the head ports that are flat? I know this may be confusing and if you need pics i could happily post them.

And another thing, I did not find an oil pump gasket in the full gasket set I bought, Would it be necessary to use one on the oil pump? or would it be fine?

This isn't that difficult, I pretty much know what you are talking about. The head ports are kind of flat, yeah, that's OK, not the greatest, but it is OK. Remember, flat surfaces tend to go "stale" in the sense that the air doesn't have anything to control that flow at low rpm, thus the carbide burr cutting surface I always recommend, but not all four surfaces are totally flat, there are curves and slight bumps throughout the port to the bowl under the valves. Transition is what you want. In other words, right at the port where the gasket is, yes, that should be very similar, but not necessarily very deep (say half an inch), until it meets up with the curve. The curve controls the flow to the head, but it doesn't have to be flat all the way, it just isn't possible, so you make a transition from the curve, from oval to square, from round to square (you get the picture I think). I will constantly talk about the carbide burr cutting surface and always hate the glass smooth, or sandpaper polished surfaces because of these flat areas. They are kind of like ice in that there is no flow control, so fuel can separate from the air at low flow speeds, but with the carbide burr cutting surface, the little "chips" in the surface, which you can see and barely feel, work like little flat bowls, and when you try to skip molecules of fuel into them sideways, they skip out into the flow and don't stick to the walls, causing puddles or evaporating and coking (separation of the chemicals, gunk in the port over time). Sandpaper roll scratches like to catch the molecules or make them "catch and skip" and separate, polished is like throwing an ice cube on a hot griddle, it just dances around at low speeds, like the rain on a clean windshild, the fuel slides across the surface.

As far as the gasket for the oil pump goes, you can get some wet/dry 400grit sandpaper and ensure both the attaching surfaces are flat and smooth (I use a sheet of glass for flatness, lay it on the bench, place a little solvent or lacquer thinner on it, then the wet/dry, then some more thinner on it and do a cross sanding pattern to ensure the light sanding marks are flat and all the way across the face in both directions), and if both are flat, you can use no gasket if desired, it is same as the factory. If you still feel you need one, heavy paper bag is the equivalent of the replacement gasket.

[dana44]

73_duster, on Jul 2 2008, 09:24 PM, said:

Thanks for the advice, I have the intake ported to match the heads pretty well except, there are a 2-3 ports that have a side or two that is very slightly smaller than the gasket (the heads excactly match the gasket). But would it make a difference at all if those sides were maybe a little under a fingernails height smaller than the gasket? if it does should i try to trim it down slightly with an exacto knife?

And i will try the carbide burr cutting you were talking about on the intake manifold, but my dad says i can't try it on the heads (im still 16) because they were fully ported by a supposedly famous todd/tedd mickenley. For the carbide burr cutting, would i use what looks like a small oval shaped tool on the dremel that feels like a 400 grit sandpaper?

The dremel ones are pretty small and take quite a bit of time to cut, but aluminum is lighter and easier to cut. I like the one that is about the size of your little finger, round on the end, about 1.5inches tall, the sides would remind one of a barber pole, kind of striped cutters going from the tip and then slightly curving around the body. An aluminum one is very course, with about 10 stripes on it, a steel one has about 22stripes on it.

The amount of difference you are talking about, fingernail thickness, could be adjusted with the gasket and manifold sliding back and forth on the bolts themselves, there is a small amount of play there, but it is definitely less than the stock offset, which could be as much as 3/16ths of an inch to 1/4inch difference, so the idea is to get it as close as possible when all else fails.