Cat 3116 engine swap into blue

[dahoyle]

OK, I'll give you the at idle thing, but I really like the skid plate/ vacuum thing. Why, once you hit 80 or 90 and that... Oh, I just thought of a problem lol
Louvering the inner fender doesn't work so well from what I've heard. Great idea to keep the exterior sheet metal looking stock though. I was never sold on Barry's cowl vent idea. I seem to remember that he was happy with the result, but the idea of a cowl vent is to let air INTO the engine compartment, not out. Again, this is assuming a much higher average speed than a 715 would normally achieve.

Dahoyle would you have a pic of that. I understand what you are saying, I just cannot picture it in my head.

No pic of it, but if you just pop the hood, I think you will see what I mean.

[kwai]

Both Tom and Barry's solutions were to allow more air to flow through the radiator and out of the engine compartment. When you fill the compartment with a big engine and all the accessories there isn't much room for air movement. Thus the vent provides an outlet for the heated air from the radiator.

[brute4c]

Looking at an M715 cowl area from an airflow standpoint...the air in front of the flat windshield is going to move outward and upward in a wake well before it gets to the windshield...in the case of a sloped windshield different things happen but with the flat windshield, the air is moving out of the way well before it gets to the windshield...so there is high pressure, low speed, practcally stagnant air, at the cowl.

If you ever drive with snow on the hood and dont clean it all off before driving, you can see the aerodynamics in action...at the cowl, the stuff just sits there...no flow...not toward the engine, not away from it...just stagnation.

Remember why the rear window in the R model Mustangs didnt meet the roof line? To vent the low speed/high pressure air in the cabin and pickup a couple tenths in the quarter.

Essentially, the cowl area being vented via the hood in this application is a very good use of the available design.

The added flow in the cowl area from the vent will actually help aerodynamics by helping the approaching airstream coming over the hood to actually get pushed out of the way of the windshield sooner and therefore cause a little less flat plate drag...essentially it will slightly reduce, at speed, the frontal area.

[brute4c]

I found this shot...you can just see the back opening of the cowl:

[Ronner]

IIRC he didn't add anything to the hood, just cut back the original metal at an angle.

[snakeater]

I like the look of that hood. i don't think I would do it to mine unless I had to. I want the outside to look as stock as possible. That being said, I will modify anything that is needed to clear essential components. but it will be a last resort kinda thing. Snakeater

[kwai]

I think another factor in the hood modifications on both barry's and tom's trucks was the addition of the 427 tall deck which needed a little more clearance up top.

[Ronner]

Nah, B. did the same w/o altering the hood. Barry & Tom had theirs hot rodded a bit and rung the pizz out of them - that's why the extra cooling capacity was necessary.

[snakeater]

I have been trying to locate a shifter for the allison at542 transmission. called 5 or 6 places and no one seems to have one. i know that they were used in isuzu, gmc,chevrolet and a few others. What is so special about this shifter? Everyone has the transmission, just no shifter for it. I was trying to find a stock one and modify it to use in my truck, but I may have to back up and punt. Wonder if it shares the same gate length as anything else? More importantly I wonder if anything else can be used in its place. I spoke with northwest fab about their cable shifters for the transfer case, and they are more than happy to make a shifter for me to use on the trasmission, but it won't have any detent or gates in it. That scares me a little in that if it was used there would be nothing to lock it into gear. Any bump or jar could knock it into another gear.......bad juju. The search continues snakeater

[dahoyle]

I have been trying to locate a shifter for the allison at542 transmission. called 5 or 6 places and no one seems to have one. i know that they were used in isuzu, gmc,chevrolet and a few others. What is so special about this shifter? Everyone has the transmission, just no shifter for it. I was trying to find a stock one and modify it to use in my truck, but I may have to back up and punt. Wonder if it shares the same gate length as anything else? More importantly I wonder if anything else can be used in its place. I spoke with northwest fab about their cable shifters for the transfer case, and they are more than happy to make a shifter for me to use on the trasmission, but it won't have any detent or gates in it. That scares me a little in that if it was used there would be nothing to lock it into gear. Any bump or jar could knock it into another gear.......bad juju. The search continues snakeater

You can use any 4 speed shifter, you just have to make sure that you make a shifter tab on the transmission, that is the right length relative to the shifter you use. Might take some trial and error to narrow it down, but it should be dead simple.