peejay

Sheesh.

Four hours, two sanding rolls, one grinding stone, and one set of drill bearings destroyed, and I'm still only about half done modifying my '83 intake manifold to '79-80 spec.

Well, that's not QUITE right... this is the manifold I started last year, the one I ran on WT. I'd already blocked off the channels between primary and secondary runners (note: do NOT do this - it really hurts power) blocked off all emissions passages including the shutter valve shaft holes with JB Weld and smoothed out the lumps-n-bumps in the secondary ports.

Right now, all I'm doing is opening up the #1 primary runner to the same size as the #2 primary runner. Actually, where it is now looks really good, and I might simply fill in the #2 primary to match it. Before I started, I was worried that porting it open might break through the side of the manifold, so I built-up the area with a card's worth of JB Weld. (that makes it 4 cards in the manifold ) Right now the 1P opening is the same size as 2P's, and it is a smooth taper all the way in to where the port starts to turn. By contrast, 2P is the same diameter all the way to just before the turn, and then it necks down severely.

Yes. That is what I'll do. I'll rough-up the sides of the 2P runner and put some JB Weld in there and then taper it nicely. Should flow better, and besides, JB Weld is a lot easier to cut than aluminum, and it doesn't clog up the stones and bits either.

After that's done I'll re-open the 1P/1S channel and create a new, identical one between 2P and 2S. Bewdiful. And then I'll alter the short-side radius on 1P and 2P so that they have a nice D-shape, for less turbulence.

This is gonna be GOOD.... It better be, this is definitely the hard way to having a 79-80 style manifold...

79+80_rx-7

why not, just go get one??? Just a thiught

peejay

Cos I'm a bastard

Yes I have one... however it would need to be modified to be used on a later engine, because it won't cover the air injection port in the center housing. I don't want to do that. Plus, it LOOKS like the secondary runners on the '80 intake will need a lot more work to be as smooth as the ones on the later manifold. Big lumps and bumps that'd probably break through.

It's a case of "well, I already have this one partially modified, let's take it a step further". Trust me, I would not do this again unless absolutely necessary. I will hang on to this manifold like gold 5 years from now it'll probably be a solid block of JB Weld with no actual aluminum left

mperformance

peejay

Here's a bad pic of where I'm at so far... note the new channel between 2P and 2S, and the fact that 1P is much closer to 2P's size...

Directfreak

iTrader: (2)

JEEZ Peejay.. Wouldn't some things just be better to buy?

peejay

Heh... You buy it for me and I'll try it!

Sterling

Cheap bastard!
I've wondered about sand casting my own. I don't ever sand cast in silver or gold, but because I'm in the trade, I know a few bronze and aluminum casters. They make sculpture and bells and **** in bronze always with sand casting (like the original manifolds).
I would have it cast in two halves like the Dellorto manifolds or the DCOEs for ease of clean-up inside with a flex shaft.
Hmmmm.
Question is, are there enough Cheap-Asses like peejay to cover my costs?

I do what he's doing for a living, every damn day! Cleaning up crappy castings is a real pain in the ***.

Peejay - How many times so far have you got a nice fleck in yer eye?!

peejay

I wear glasses AND safety goggles.

Too many times a day.