red91

Yeah just not as smooth and svelte.

Mike1998XJ

Red:
Do you think you need that much of the hood to be the vent? What will you do for structural integrity?

4.3L:
Wow it is true then... You really do have a 4.3 in there. Could that engine have a Supercharger mounted to it? Say off a Bonneville SSEI? The triangles are kind of close to the front. Will they be flat Louvers for heat dissapation up and out of the engine compartment? or forward or rearword facing scoop type louvers that either ram air in or draw air out? Sounds like they would be flat made out of the Aluminum you mentioned. If your passing through Michigan I have an old hood you could have to experiment with various sized holes and locations.

red91

I was thinking that using the hood crease it would be easier to fare in, and that by making it that wide you would only have to raise it an inch or so. Like I said you would have to reinforce the back edge. Which could be done with when you filled in the opening with your screen or grill. I would have to look tomorrow but I don't think the hood panel is welded to the stiffener if not it would just be a matter of installing some ribs between the stiffener and the top panel before you welded in the filler and fare it. Sounds simple I wish life was as easy as my imagination.

4.3L XJ

The louvers will be attached to the hood "frame" and so will loose no integrity. The problem I am having right now is two fold. First, I can stay cool at low speeds all day long. But when I travel at speed, I loose air flow under the hood. It just gets hot enough to start melting stuff and I am loosing the head gaskets at the back of the engine. I am getting tired of replacing them and the cab temps can get real hot on a hot day. If I just take the hood off, the problems go away. Second, the 4.3 is designed to have a oil cooler on it. So I am adding one.

With my front bumper configuration along with the lift and the larger V6, there is just no air flow in the engine compartment and it will not stay cool on a hot day even with a Griffin radiator. So I am really going after the air flow and if it looks like I am going after over kill, well I am because I am going to add more horse power. With some factory heads and a custom cam ground to LS1 specs you can get 300 hp out of one and still pass smog here in CA. With a belt driven turbocharger you can go to 450 hp. My tranny is built for it, I'm putting in an Atlas and custom axles to take it. But I will have to keep it cool or it won't work at all.

There was a factory motor called the Syclone with 280 hp that had a turbo, but it was rare as hens teeth.

Mike1998XJ

So the fans for the oil coolers will draw it out the back of the hood. Ok. I can see that.

4.3L XJ

They are reversible, but what I am trying for is to force air down the firewall and back of the engine and cycle the air to the front and out with the slight vacuum created by the louvers. I really need to get rid of that trapped heat. I am also adding larger fans to the shroud. These pull 2000 cfm apiece

red91

4.3L XJ
I was going to ask you how you kept that wicked motor cool with all that stuff under it but you already answered my question. Are you sure those two triangles are going to be enough? I think a bug deflector or something similar would be in order also to help give some negative pressure above those louvers.

4.3L XJ

We'll see what happens. I am just doing this as I go, sort of according to plan