Mustang #315

I am installing a Dr Gas Crossover Pipe. This will help equalize the pressure between the 2 sides of the exhaust. This should add a bit of torque, and also quiet the exhaust down a little. I got the measurements from Scott on where exactly it needed to be (and not be) to optimize the torque curve. Amazingly, I’ve been able to nail the placement of the center of the X very close to ideal, about 35.9 inches from the ends of the primaries inside the header. This got a little interesting, because since the primaries on the left and right are different lengths, the collectors are different lengths as well.

I pulled a rookie move when I welded the center section together – I welded it all on one side and then the other. MIG gets really hot, so the metal warped a bit and threw off my nice fitment job.  I muscled it into place anyway. Hopefully that will work out.

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Dad and I went over to Ray’s for the final engine assembly. We made a couple mistakes. First, we forgot to install the fuel pump eccentric! No matter, it forces me to go electric, which will be great. Second, we didn’t realize that htis type of lifter needs to be installed before the heads. oops. Otherwise, the assembly went great and the motor looks good.

The dial indicator helps us find top dead center

finding TDC

The windage tray goes on. We had to machine these holes to fit. It seems that everything needs customization.

Dad puts on the head for the first time. I'm putting molybdenum disulphide on the head bolt washers so that they have a smooth bearing surface.

Initial torque. We torqued the head bolts in 3 steps.

final torque

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lifters, pushrods, and rockers are in

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looking good!

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One of the things about my old transmission was the sloppy shifting. Anyone who drove it could tell you,  you never really knew for sure if you’d shifted into a particular gear. Well, I bought a new Hurst Competition Plus shifter, part number 391 3180, and took it over to Ray’s. We took apart the old linkage and cut the rods to the proper lengths. Then, we threaded the ends and installed heim joints. Where new bushings were needed, Ray machined some new ones out of stainless steel on his lathe. Then, he took apart the Hurst and made shims for every gear. This process basically took out all of the slop and left me with a REALLY nice shifter.

This is the old shifter - an old Hurst style one, but not the right one for this transmission.

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You can see how the attachment is made between the rods and the transmission arms - the rod makes a 90 degree turn into that hole. There are plastic bushings (teflon?) that smooth the joint out, and the rods are then secured with a spring clip.

We replaced the old sloppy joints with really nice solid heim joints that took out all the slop

The heim joints are fastened with AN 365 lock nuts. They're not going anywhere.

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Ray shimmed the shifter perfectly, so that there is no play in it. Very nice feel to the shifting now.

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My friend gave me a killer fuel filter – Mallory 3140 – but it was missing a mount bracket. I made one out of 16 gauge sheet metal.

I cut this sheet metal with an air shear

On the left is my fuel filter. My friend gave it to me, but it came without a mount bracket. No problem!

I drew out the pattern, marked the line for the screw holes, and hit the hole locations with a center punch before drilling. the center punch makes drilling so much easier - the bit won't have a tendency to "walk"

bent up the back in my vise, and ... finished! I should really have made a bigger mount bracket on the back. I didn't cut enough metal initially though, and this should be good enough.

My friend sold me this sweet carb. It’s a Holley 4150 that’s been rebuilt by The Carb Shop to their stage III race carb specs.  I did some rebuild work on it – replaced gaskets, cleaned all the old varnish out, replaced the power valve and accelerator pump diaphragms, replaced the fuel sight windows.  I also tapped and helicoiled the air filter mount and set the accelerator pump clearances.

I cleaned out all the old gas varnish with q-tips and carb cleaner.

With the throttle valves removed, this is the bottom of the carb

This is a really nice carb that my friend gave me a great deal on. It's a Holley 4150, but it's been rebuild by The Carburetor Shop to their Stage III race carb specs.

carefully cleaned off the old gasket material from the metering blocks

These old accelerator pump diaphragms have seen better days. replaced!

Shiny new accelerator pump diaphragm

After installing the new accelerator pump diaphragm, I set the travel of the pump actuator. Set the carb to Wide Open Throttle, push the pump arm to full on, and set the screw so that there is .015 clearance. This prevents you from tearing the diaphragm at WOT.

The air filter mount bracket was stripped out. This 1/4x20 Helicoil took care of that no problem.

Carb put together. You can see I removed an unused vaccuum port and put in a 1/8 NPT set screw in its place as a plug.

These are some of the latest from the engine project. Dad and I are working on it with Ray at his place.

Taking another page from Ray’s book, I’ve decided to do some seam welding. I’m doing 1″ welds, a couple inches apart, along some of the frame rails, where they meet the body panels. I guess the stock spot-welds aren’t that great as far as torsional rigidity. anyway it’s an easy enough way to add some stiffness into the body. I’m also going to weld the shock towers. There is bracing where the control arm fasteners come through the shock towers. It’s spot-welded in place and since I’m going to be asking a lot more of those joints with the larger tires and the higher speed corners on the track, I’ll go ahead and weld around those seams as well. I might not worry about it with the frame rails that I already welded to the new floor pans, because I know I welded those really strong.

I have FINALLY finished welding in the rear suspension mounts. Most of it went well. On the driver’s side I blew through the frame rail and had to build it up. The result is ugly as sin, but will hold the thing in place.

Now it’s getting cold out in the garage! Harder to get motivated to go out and work on the car. Actually this project is feeling like such a long one that sometimes I have difficulty working up the motivation to go out and work on it. I know it’s on the down-hill side of it now though.

Dad and I will be working on the motor at Ray’s over the weekend of the 19th. I can’t wait to get that together and get this thing running!

I’m going to have to replace my headers, but I thought I would go ahead and measure my current Doug Thorley Tri-Y style headers so that Scott can see if my current ones will do in a pinch. Here are the current dims:

I first measured the primary tubes. I measured them from the top, so it’s longer than from the side or bottom, but it was the most accessible, and it’s at least consistent. I’ll list the primary tube length, which is from the non-gasket side of the flange, to the first weld joint where they go into the secondary tubes. I’ll also list the overall length, which includes the length from header gasket to collector gasket. Besides the primary tubes, I measured the other tubing on the side of the bend so that’s more neutral.

1: Primary: 11.75, OAL: 39.3
2: Primary: 9.5, OAL: 37
3: Primary: 11, OAL: 33
4: Primary: 11, OAL: 33
5: Primary: 14.25, OAL: 39
6: Primary: 14.25, OAL: 34
7: Primary: 9.25, OAL: 36.55
8: Primary: 9, OAL: 31.3

Collector Length: 5.25
Collector ID: 2.35-2.4
Primary OD: 1.5
Secondary OD: 1.75

Primary tube openings at header gasket: 1.15-1.25 W x 1.6 H

1,2 share a secondary. 2,4 also
5,7 share a secondary. 6,8 also