Things to do before installing a engine or headers

[Bob Gaines]

I thought I would start out with a problem that many complain about before installing headers that don't fit or exhaust manifolds that hit shock towers. The installer may not know what is causing some of their problem.  It is somewhat common for the shock towers to slightly sag inward over time. I and others have referred to the phenomenon as big blockitis . It can effect smallblock engine cars too but predominantly it effects heavy bigblock engine cars. The sagging inward shock tower decreases clearance between the engine and the shock tower. If you install your engine or try and install headers without checking the shock towers for sag first you may make your life a little more stressful. I typically uses a original export brace as a measuring tool .I know a original is made right. If it drops on and lines up at the cowl and more importantly on the three upper shock bracket hold down bolts then your shock towers have not moved . Many people mistakenly think that it is normal to have to fight to get one in place. That is not supposed to be the case. If it doesn't fit one or both have moved.  I have successfully used a porta power to make adjustments bought at Harbor freight. https://www.harborfreight.com/4-ton-heavy-duty-portable-hydraulic-equipment-kit-62115.html .Don't forget to use a harbor freight 20% off coupon . You put it between the shock towers and spread the shock towers.You have the export brace laying on top so you can keep track of your progress. You spread a little farther then you need because once you release the tension from the jack the shock towers will have a tendency to spring back a little.You would be amazed at how much clearance room you can get with a slight shock tower adjustment. You can do this with the engine in the car but it is much harder to get good clearance (remove carb etc)  for the ram . I have successfully made the adjustment with the engine in the car but much easier without.  Lets keep it going and hear about some other tips.

[shelbymann1970]

Thanks for the insight Bob. An old friend of mine in the 90s bought a 67 390 Coupe uncut drag car. Weird car as deluxe interior and such but was drag raced. No rust. low miles. Well after painting he went to put on a one piece export brace-had to jack out the towers. Realign the fenders and such. Now I had the same problem with a Bullitt Mustang that you would think went through the same jumps as the original stunt car. Shock towers were off a lot to me. I made my own jack using black pipe. Threaded rod nuts and some welding. Jacked the towers out until the 1 piece brace fit. My SCJ had a 1 piece brace on it(real Ford unit) and fits great but header bolts touch the shock towers. I like the porta power idea better. Gary

[Jim Herrud]

You could also check the frame dimensions in the engine bay.

It seems that the "George W. Liskey" frame dimension drawing is the usual reference for '65/'66 Mustangs, but I believe this document has some issues. This was the reference drawing at 2 frame shops that I've used over the years. If there's a better '65/'66 frame dimension reference, I would appreciate it if anyone would let us know.

In 1992, my frame was straightened in accordance with the Liskey dimensions. The OEM Ford engine components fit OK.

In 2016, I discovered I could not install a TCP steering rack or a set of Stan's Tri-Y headers because the engine bay was too narrow. I took the car to be re-examined by another frame shop. Like the first frame shop, this second shop also had the Liskey drawing in their "Big Book 'O Dimensions" for the '65/'66 Mustangs. They confirmed that my frame dimensions match the Liskey drawing. However, the shop owner said he could tell visually that the frame was not straight. I allowed him to straighten the frame again until he was satisfied (using his experience) that it was true.

After this adjustment, my new steering-rack and headers fit fine.

A few weeks later, out of curiosity, I enlisted the help of some friends from my local Mustang Club to let me measure this "G" dimension on the frames of their unmolested '65/'66 cars. Here's what we found:

66 GT-350: 22 3/8"
66 Coupe: 22 5/16"
66 Coupe: 22 5/16"
65 Fastback: 21 1/2" (my car before 2016 straightening)
65 Fastback: 22 1/4" (my car after 2016 straightening)

The Liskey drawing note for Dimension G says:

"G – 21 ½  - Center to center of R and L lower control arm inner pivot points"

So, this dimension appears to be incorrect. However, I noticed that my car's current dimension between the two lower engine-mount holes is precisely 21 ½". This suggests another possibility: perhaps Mr. Liskey had the dimension correct, but he attributed it to the wrong location. Perhaps the note should say:

"G – 21 ½  - Center to center of R and L lower engine-mount points"

I realize this is a small sample size, but it did mitigate my problem. Just thought I'd throw this out there in case others have a similar issue.


One more thing: I've found forum reports that other parts of the Liskey drawing, specifically those at the back of the car are also incorrect. I have no data to properly assess these reports.

[Bob Gaines]

You could also check the frame dimensions in the engine bay.

It seems that the "George W. Liskey" frame dimension drawing is the usual reference for '65/'66 Mustangs, but I believe this document has some issues. This was the reference drawing at 2 frame shops that I've used over the years. If there's a better '65/'66 frame dimension reference, I would appreciate it if anyone would let us know.

In 1992, my frame was straightened in accordance with the Liskey dimensions. The OEM Ford engine components fit OK.

In 2016, I discovered I could not install a TCP steering rack or a set of Stan's Tri-Y headers because the engine bay was too narrow. I took the car to be re-examined by another frame shop. Like the first frame shop, this second shop also had the Liskey drawing in their "Big Book 'O Dimensions" for the '65/'66 Mustangs. They confirmed that my frame dimensions match the Liskey drawing. However, the shop owner said he could tell visually that the frame was not straight. I allowed him to straighten the frame again until he was satisfied (using his experience) that it was true.

After this adjustment, my new steering-rack and headers fit fine.

A few weeks later, out of curiosity, I enlisted the help of some friends from my local Mustang Club to let me measure this "G" dimension on the frames of their unmolested '65/'66 cars. Here's what we found:

66 GT-350: 22 3/8"
66 Coupe: 22 5/16"
66 Coupe: 22 5/16"
65 Fastback: 21 1/2" (my car before 2016 straightening)
65 Fastback: 22 1/4" (my car after 2016 straightening)

The Liskey drawing note for Dimension G says:

"G – 21 ½  - Center to center of R and L lower control arm inner pivot points"

So, this dimension appears to be incorrect. However, I noticed that my car's current dimension between the two lower engine-mount holes is precisely 21 ½". This suggests another possibility: perhaps Mr. Liskey had the dimension correct, but he attributed it to the wrong location. Perhaps the note should say:

"G – 21 ½  - Center to center of R and L lower engine-mount points"

I realize this is a small sample size, but it did mitigate my problem. Just thought I'd throw this out there in case others have a similar issue.


One more thing: I've found forum reports that other parts of the Liskey drawing, specifically those at the back of the car are also incorrect. I have no data to properly assess these reports.

Jim ,your experience is why I use the export brace as a measuring tool.It is just as accurate IMO plus easier to use. Of course the method I use is only meant to solve a typical shock tower sag and not frame damage. A long time Shelby restoration shop R+R Motorsports uses the export brace as a measurement tool after lower frame damage has been repaired on a frame machine just as added insurance all measurement are nominal since he knows the brace has to drop on when everything is done.  Since we all know a export brace is meant to be used on all 65-68 Shelby's (69/70 dimensions are the same) if it drops on with no fight you know you got it right. Just the way I and many others do it . There are other alternate methods . The point is to check to see if you have the problem how ever you go about doing it.

[8T03S1425]

Thanks Bob. I think I have Big Blockitis and may need to spread my shock towers a tad.

When I removed my export brace it was tight. I scratched the cowl area of the car where the 4 bolts and nuts secure it to the car. I also think it was slightly tight on the beehive retaining bolts.

Before I buy and use the hydraulic ram, is there a technique where the car can be jacked up and supported from under the front sub-frames with jack stands that will produce the same results?

Is the engine cross member strong enough to use as a jacking surface?

Do you think that using the hydraulic ram, in concert with suspending the car from under the front sub-frame rails or engine cross member aids in getting the export brace to fit better?

Oh, by the way, I also heard that using hydroxychloroquine in the engine coolant will not cure Big Blockitis. I expect the technique you described to be more effective.

Steve

[Bob Gaines]

Thanks Bob. I think I have Big Blockitis and may need to spread my shock towers a tad.

When I removed my export brace it was tight. I scratched the cowl area of the car where the 4 bolts and nuts secure it to the car. I also think it was slightly tight on the beehive retaining bolts.

Before I buy and use the hydraulic ram, is there a technique where the car can be jacked up and supported from under the front sub-frames with jack stands that will produce the same results?

Is the engine cross member strong enough to use as a jacking surface?

Do you think that using the hydraulic ram, in concert with suspending the car from under the front sub-frame rails or engine cross member aids in getting the export brace to fit better?

Oh, by the way, I also heard that using hydroxychloroquine in the engine coolant will not cure Big Blockitis. I expect the technique you described to be more effective.

Steve

Lifting the car by the crossmember is a technique that can be used to get a export brace to fit on problem shock towers but it is not solving the problem. The lifting up the car by the crossmember in the center (rubber pad on floor jack prefered) will allow the upper portion of the shock towers to spread out enough to get the export brace on but once the jack is taken out things will flex back into place. Some of the lower portion may slightly flex back while the upper stays spread out with the brace on. Besides you need the shock towers to be spread out while you work with export brace off for typical Shelby/Mustang header installation. Yes, the engine cross member is strong enough to use as a jacking surface and I use it as a lifting point all of the time . With that said you have to be very careful. You have to be careful to position your jacking pad so that the pad surface is centered front and back contacting the crossmember for balance while also having the the crossmember centered side to side on the pad for balance. You also have to be aware that the pad is positioned so that it does not catch the back edge of the oil pan sump and dent or scratch your pan.sometimes too big of a pad will catch the oil pan as the pad reaches the crossmember . I would not lift the car and use the ram at the same time because the balance is too precarious. In fact I would not suggest doing any work on the car while up on the crossmember . If you want to do work on the car put it on jack stands. In this case jack stands would defeat the purpose of raising the car. It would be too easy for the car to get knocked off the jack pad with minor josseling . The consequences of a fall could be minor to catastrophic to car and humans alike. Falling off of the jack pad is not worth the the possible down side in my book. Also remember if lifting by the crossmember to use a brace constructed like what is in the shop manual to brace the upper control arm from over extending . You can use blocks of wood in a pinch. The flex on upper shock bushings and strut rod bushings from the suspension hanging is many times too much for them to handle and the rubber may split. Especially if it is older. I think I covered everything but if someone sees something I missed please jump in. 

[shelbydoug]

Oye!

First off, let me thank Professor Gaines for pointing out technicalities that might be effecting the fit of your headers. That IS excellent technical information that does need to be put out there.

Here's the problem. If you are following that course of action,  you are as Confucius said, "setting a cannon to kill a mosquito".

You are drinking hydrolaquack-sa-queen to fix your reseeding hairline?


Point. Counterpoint.


The Mustang chassis flexes. The front rails twist a little. This is in fact acknowledged by Ford in the use of the export brace on most PRODUCTION Shelbys. It is further acknowledged by the addition of a steel plate bolted to the floor of production convertibles which really flex like a Olympic spring board.

The aftermarket has agreed with that first by adding a "Monte Carlo" bar to the 64 racing Falcons, and connected the lower control arms with an extended Trans-Am lower chassis brace by virtually every team.

Racing car chassis preparation on a Mustang includes (or should) welding all the intersections of individual chassis sheet metal components. It's basic.

The only way you possibly could get rid of what really is normal chassis flex is to build a "bird cage" Masarati type chassis. Cross bracing all over the place that results in an automotive climbing gym.



Occam's Razor. The simplest answer is usually the right answer. That is, you have a lousy set of headers that don't fit right out of the box, made by a company that is "infamous" for making mistakes in "universal" concepts of header fit.  Deal with those symptoms.



Just because your feet hurt, doesn't mean you have a brain tumor. Maybe get a pair of shoes that fit and don't squeeze your toes?

Maybe just first wipe the chassis down with Clorox wipes? Could be a community of chassis mites conspiring to screw with your head? Probably the Russians behind it? Those SOB's never sleep? Bastards! I hate those guys! 

[2112]

I see it just the other way around. If there is an underlying problem, correct that. Don't find a work around.

When I build a house, I want a solid foundation supported by bedrock, not a minimum thickness slab sitting on sand.

[shelbydoug]

I see it just the other way around. If there is an underlying problem, correct that. Don't find a work around.

When I build a house, I want a solid foundation supported by bedrock, not a minimum thickness slab sitting on sand.

Sure. Nothing like the scientific method?

A 1/2" variation is within the original build specs of the car. Let's all run around any yell, "the sky is falling, the sky is falling", Chicken Little?

Obviously you take exception to Occams Razor? You must be a medical person or something? 

[roddster]

  Good information if you have a 65/66 car.  Are the diamentions the same for the 67/68's and the 69/70'S?
   A more exacting placement for the Porta-power is wanted.  Do you put it right on plane with the upper control arm mounting, or somewher higher, or lower?
Thanks

[shelbymann1970]

Thanks Bob on your take on the shocks and strut rod bushings. I never considered the stress on those when having the car up on jack stands with a tire off. The tool you talk about I made one up almost 40 years ago but have only used it to change a bad LCA safely. Right now with shocks off I have my Mach1 on jack stands on front rails with tires off and shocks disconnected. So you think I should correct this situation immediately? BTW oine of my friends says the safest ways to remove front coil springs is to disconnect the strut rods and shocks,  then jack the car up for full extension and the coil springs will usually pop right out. Have you ever done this? I have always used a coil spring compressor with GREAT caution. Gary

[Bob Gaines]

  Good information if you have a 65/66 car.  Are the diamentions the same for the 67/68's and the 69/70'S?
   A more exacting placement for the Porta-power is wanted.  Do you put it right on plane with the upper control arm mounting, or somewher higher, or lower?
Thanks

With the exception of the even spaced bolt pattern on the a 65/66 GT350 the 65-70 export braces are the same. The 67 70 export brace with its unequal bolt spacing is used many times on stock 65/66 Mustangs that don't have the special export/Shelby brace support with equal spacing welded into the cowl. With that said yes it fits the 69/70. When you are trying to spread the shock towers with the engine in the car you don't have many choices and you place it as low as you can . If you are up too high the ram rods will slip off the slanted contour of the upper portion of the shock tower.  With the engine out I have typically placed it slightly higher then the upper control arm mounting for better leverage . If the top part of the shock tower moves the bottom moves too . It moves altogether .

[Bob Gaines]

Thanks Bob on your take on the shocks and strut rod bushings. I never considered the stress on those when having the car up on jack stands with a tire off. The tool you talk about I made one up almost 40 years ago but have only used it to change a bad LCA safely. Right now with shocks off I have my Mach1 on jack stands on front rails with tires off and shocks disconnected. So you think I should correct this situation immediately? BTW oine of my friends says the safest ways to remove front coil springs is to disconnect the strut rods and shocks,  then jack the car up for full extension and the coil springs will usually pop right out. Have you ever done this? I have always used a coil spring compressor with GREAT caution. Gary

Gary , if the suspension is hanging then yes I would put the brace in before it is too late for the rubber. I always end up using a spring compressor.

[2112]

Bob,

Since the shock towers are smooth and sloped, how do you keep the hydraulic press in place as you are pushing the towers back out to the proper location?

Do you let it (the press) sit with the press in place for some time before moving on?

[Bob Gaines]

Bob,

Since the shock towers are smooth and sloped, how do you keep the hydraulic press in place as you are pushing the towers back out to the proper location?

Do you let it (the press) sit with the press in place for some time before moving on?

The porta power I use which is similar to the link i posted has rubber pads on each end of the ram rods. AS i mentioned previously it is only a problem if trying to push at the upper end of the shock towers where there is a more significant contour . That is in a engine installed situation.