Shelby Drop done, but there's problems

I thought these cars used the wider bolt spacing cross shafts on the 68 on up arms?

 

They do...

BTW that'll be '66 up for Fairlane/Falcon & '67 up Mustang/Cougar...

 

My bad, thanks for pointing that out. I've always taken measurements from the actual parts when making my own templates. Have done early Falcons as well but never noticed the cross haft difference.

 

I will make some templates once it is apart, but in the meantime, I am wondering if the 1/8" backspacing for the bottom hole should be more like 1/4" ? That would double the caster angle? If 1/8 is close to stock, double would be good? See, I have lots of questions, cuz I am at the bottom of the learning curve right now.

 

The a-arm is moved down and rearward parallel to the factory centerline. So both holes are moved the same amount.

 

Thanks Tom. I realized I was off a year after I typed and posted it but just got too lazy to correct it.

No prob, Bob. I figured that you've probably forgotten more than I'll ever know about these cars and if anything was guessing I had a memory bank error. Actually kinda nice to know I learned and remembered something right for a change. lol

 

I can't stress enough the importance of arming yourself with ample info before doing any suspension mod's of this type. Decent all-around info right here and plenty more when you google it.

http://dazecars.com/dazed/drop.html

As for the best drop template to use?.. I have strong opinions on the matter after having owned, modified, tested, and driven around in many friends and relatives cars with this same mod over the years. There are two types that can be used with one being superior to the other, IMO. One type is a straight drop style template where the bolts drop down absolutely and perfectly perpendicular and square to the original bolt hole locations(no rearwards offset). The template will have new holes parallel to the old ones and on the same hole centerline axis as well(perfectly square 4 hole layout). IMO, this is the absolute wrong way to go here and seems to be the leading issue for those having front tire to valance clearance issues. What happens during that type of drop is that the arm moves forward in the WRONG direction towards the valance as the control arms mounting position is lowered in the angled shocktower.. then forcing them to adjust their strut rods to put enough/extra castor back in it. The ones doing the heavier drops over 1" pay the biggest price for lost castor potential. IOW, since the control arm is already canted to begin with.. using a straight drop template that has the new holes exactly parallel and square to the old ones will cause loss of caster over the already poor factory settings to begin with. Trust me here.. you will want a bit more caster than recommended.. rather than have less. Unless you have full aftermarket suspension.. it's pretty tough to get too much caster into these suspensions. Unless you don't mind your tires hitting the front valance, you'll be lucky to reach well beyond about 2° if you use the wrong template. Use the second type I talk about below and you can get to the higher numbers without hitting the valance as quickly.

The second type is often referred to for use with the earlier 65-66 Mustangs but those cars have a narrower bolt spread that prevents that specific template from being used here. However, if you study that particular template in detail you will quickly notice that the new hole locations resemble a parallelogram(off-axis or skewed looking square) to compensate for the naturally occurring forward movement of the control arms true North/South centerline as it's dropped lower in the angled tower. So, your thinking is correct from a geometry standpoint in that adding an 1/8" rearward offset will just put you back to the arms original true centerline after the drop is complete. Unfortunately, I have never been able to move the control arm rearward much more than about 3/16" simply due to the fact that I prefer more aggressive drops(1.5" - 2") and there's just not enough available real estate to do both in larger amounts. I can't remember how much space is left for rearward offset when the lighter typical 1" drop is used but it seems doubtful that you would be able to go beyond 1/4" offset and holes will need to be punched into the shock tower to clearance the control arms end cap/bearing/grease zerk.

Besides physical restriction/clearance issues the only other negative that I know of for pushing the arm rearwards in larger amounts is that you will also lose some of the suspensions anti-dive geometry and the spring starts to bow just a bit more. Nothing too extreme or dangerous but components and bushings may start to wear funny in the process. To regain that small lost % of anti-dive you would need to push the shock/spring seat rearwards at least the same amount. Not many will go to the trouble of moving shock towers when they can just get them the hell out of their engines way while they're going to all that trouble. The last and likely the most important thing to keep in mind is the need for a relocated/angled ball-joint spacer(often called a "negative wedge kit") to prevent ball joint binding when dropping the arms any more than about 1.25". Always some trade-off, additional requirements, or other limitation involved.

Here's the typical templates most are using.

http://www.mustangbarn.com/assets/arningshelby-suspension-drop.pdf

The ones I usually make for myself and others( on larger cars than these using the same wider a-arm bolt spread) are modeled after the Shelby version to incorporate the rearward offset. These cars are very tight to begin with so you're already handicapped right out of the gate. You can also "clock the ends" of your upper a-arms shaft to allow off-setting its mounting holes forward within the a-arm itself. This has the same affect as moving the arms physical centerline location rearwards like the hole relocation does. Bolts stay in the same location.. arm moves rearward slightly. Unfortunately, this mod is limited in the amount of available offset and also causes loss of clearance as the arms move rearwards as well.

 

If I were to go to all that trouble, I would instead convert to a TCP front suspension. That Shelby mod is old technology.

 

I know exactly what you're saying but it all comes down to cash spent and degree of gain for what you're after. The bearing design on these things is barely any better than an old wagon wheel once it wears out too.

IF.. you(more people in general) had a plasma cutter(not mandatory but makes it WAY faster/more productive and cleaner jobs)/decent welder along with the room and enough expertise to do such mod's?.. you/they could save big bucks and get closer than you think to some of this sometimes overpriced tubular stuff. Cheaply stamped SLA setups like these can be beefed up and STILL be lighter overall and therefore more responsive than some of this blingy stuff. Eventually you'll find the weak links with big sticky tires vs that stouter/heavier stuff because the spindles are a weak link too. If you want strength, bling, AND lightweight.. it gets stupid expensive very quickly. The main reason for that is the spindle limitations and billet systems are continually being added every year. Did anyone see this lately?.. looks promising.

http://www.globalwest.net/

video here..

These? http://roadstershop.com/product/crossmember/fast-track-ifs-crossmember/

I've drooled over these things for a few years now too. http://cortexracing.com/product/radial-x-spindles-cortex-racing/

Expensive and far away but I still like these too. They also carry superbly modified/reinforced stock lower arms too. http://www.rrs-online.com.au/au/lemans-lower-control-arms.html

Another thing that has me shrugging my shoulders in disbelief sometimes is the amount of money that people will sink into some of these strut rod based kits and then do absolutely nothing about the downright horrible flex that occurs on the front of these cars. Can't seem to find the undercar video saved of some aftermarket strut rod based suspension installed on an early Mustang(could be TCP setup) that showed forward and rearwards movement of the strut rods cross support of at least 3/8" in BOTH directions. So, near 3/4" deflection of the supports eye! I'll keep looking but found this for now to give you an idea what even a torque wrench at 60+ lbs can do. About the 16 minute mark you can see the flexing.



I have tons of saved info and links I will try to add. Tired, rambling more than normal now, getting up earlier than usual.. talk to you guys tomorrow if the conversation's still going.

 

I thank you for such a detailed reply. I looked at the provided links as well. I am leaning toward the one inch down and 1/8+ 1 or 2 16ths back, depending upon how much material there will be after holes are made, and how much clearance there is....and I will scope out where the bolts will be on the engine side of the tower too. My interest in this mod is fueled by the minimal cost and a seemingly good improvement. And the old carpenter saying of "measure twice, cut once" is really going to be.....ask and think and ask again, measure five times, scratch my head, and then grab the drill! I will see if I can figure out what kind of net change I will be creating in the caster angle too before Grab that drill.

 

The nice thing about the TCP front end is that you can have the "Shelby Drop" built into the upper A arm so that there is no need to drill new holes. You just bolt them in.

I had no issues with front valance clearance.

Micah

 

That is also good to know. If I botch my holes, I can still get there someday when my wallet is heavier. I bought this car, towed it home, and after some research I bought some disc brake spindles and parts from a granada in the junkyard. I am into it about $800. It must remain a hobby, because (and I may be wrong) I dont think it qualifies as an investment. If it were a numbers matching v-8 car with nice options, I wouldnt be able to afford the "nice" it would deserve. So, I will "hobby" with it as best I can, learn what I need to learn (All of you in this forum are a BIG help in that dept.), and hopefully have a nice and very functional vintage(?) comet with maverick bumpers. And all the while, I am enjoying my FIRST project Ford and am wondering why it took me so long to get one.

 

you have a good attitude and seem to be keeping your head out of the clouds for now. Which is good because it's far too easy to tear into these things with good intentions only to find that there just isn't enough time and money to ever hit your intended mark. Build it in stages and enjoy it as it changes along the way.

while we're all dreaming here.. this is another one of my favorites.

https://www.detroitspeed.com/1964-1970-mustang-products/032050-aluma-frame.html