Shelby Drop Mistake - Vintage Mustang Forums
 36Likes
Reply
 
Thread Tools
post #1 of 23 (permalink) Old 06-18-2019, 12:39 PM Thread Starter
Junior Member
 
Join Date: Mar 2011
Posts: 6
Shelby Drop Mistake

So I decided to try the Shelby drop using a template I bought from daze cars. Once I got all the suspension removed and installed the template, I started with a*17/32-inch bit and drilled the initial hole (but thinking back on it now I guess my mistake was removing removing the template which I did thinking in I would have the same size template holes for the other side.) After drilling the 1/2" holes, i found out that they are not aligned correctly. They are just a tiny bit too apart from each other. I'm just curious what I can do to correct this without making a bigger mess? Should I drill one of the holes out to be 9/16"? Or should I just go with control arms like Specialty Products Company Adjustable Control Arms which give the Shelby drop from the factory holes?*

https://www.cjponyparts.com/specialt...-1973/p/UCA61/
rittenrotton is offline  
Sponsored Links
Advertisement
 
post #2 of 23 (permalink) Old 06-18-2019, 12:45 PM
Senior Member
 
68Hildago's Avatar
 
Join Date: Jan 2015
Location: Edmonton, Alberta, Canada
Posts: 748
Garage
You mentioned 2 things.: Not aligned correctly and also they are a bit too apart.

How much is a bit? 1/16", 1/8", 1/4"?

If they are only a bit too far apart (1/16") but aligned correctly, you could ream out the insides (using the original template to ensure accuracy and you do not take too much off)
zray, Huntingky, gt350sr and 2 others like this.
68Hildago is offline  
post #3 of 23 (permalink) Old 06-18-2019, 01:29 PM
Senior Member
 
Nailbender's Avatar
 
Join Date: Jan 2015
Location: Northern Indiana
Posts: 2,564
You start with an 1/8” bit, then 1/4”, 3/8”, 17/32”.

65 C Code hardtop from California still wearing it's original paint.
Roller 331, TW 170 heads, T-5z, FiTech EFI, FPA Headers, Arvinode exhaust, SoT Bilstien coilover front suspension, TJ on eBay 8" 3.40 Trac-Loc 3rd member. Mustang Steve 2008 GT bracketed 12.4" front disks
Nailbender is offline  
 
post #4 of 23 (permalink) Old 06-18-2019, 03:56 PM
Senior Member
 
mikeyhunts's Avatar
 
Join Date: Aug 2018
Location: HOUSTON
Posts: 873
When I did mine, I had one hole off by about 1/16”.
This was when I was stepping up as mentioned above, so I was not at final size.

One of the smaller steps, I went in with a little carbide bit and opened up only one side of one hole.

Then when I stepped up to the next bit, it recentered and worked perfectly.
Getting that pilot hole spot on is CRUCIAL.



Sent from my iPhone using Tapatalk
DonP likes this.
mikeyhunts is offline  
post #5 of 23 (permalink) Old 06-18-2019, 03:56 PM
Senior Member
 
mikeyhunts's Avatar
 
Join Date: Aug 2018
Location: HOUSTON
Posts: 873
Quote:
Originally Posted by Nailbender View Post
You start with an 1/8” bit, then 1/4”, 3/8”, 17/32”.


I had to do more steps than this, but my drill bits may have been dull.
It wasn’t easy drilling.



Sent from my iPhone using Tapatalk
mikeyhunts is offline  
post #6 of 23 (permalink) Old 06-18-2019, 08:10 PM
Senior Member
 
awhtx's Avatar
 
Join Date: Sep 2011
Location: The Hill Country of Central Texas
Posts: 8,815
Just use a rat tail file to elongate the hole in the direction it needs to go which is towards the other hole. You'll be OK.
Asm109, DonP, 2nd 66 and 2 others like this.
awhtx is offline  
post #7 of 23 (permalink) Old 06-18-2019, 10:10 PM
Senior Member
 
vegasloki's Avatar
 
Join Date: Nov 2017
Location: Vegas
Posts: 1,288
I just did my holes though the car isn't back on the ground yet. I used the the template from Day as well as the DIY roller perch kit. I started with an 1/8" pilot, removed the template then stepped it up to just below 1/2" where I finished off with the 17/32".

This thread can serve as a reminder that it's best to step up (by either multiple drills or step bit) to just under the finished size then finish it with the desired size. Guys that aren't used to drilling metal with larger holes may not know the ins and outs of getting the hole to the right size.

Huskinhano, Nailbender and 68Ghost like this.

67 Hardtop, brought it back to a driver
http://desertratretro.com
vegasloki is offline  
post #8 of 23 (permalink) Old 06-18-2019, 10:20 PM
Senior Member
 
Nailbender's Avatar
 
Join Date: Jan 2015
Location: Northern Indiana
Posts: 2,564
Quote:
Originally Posted by vegasloki View Post
I just did my holes though the car isn't back on the ground yet. I used the the template from Day as well as the DIY roller perch kit. I started with an 1/8" pilot, removed the template then stepped it up to just below 1/2" where I finished off with the 17/32".

This thread can serve as a reminder that it's best to step up (by either multiple drills or step bit) to just under the finished size then finish it with the desired size. Guys that aren't used to drilling metal with larger holes may not know the ins and outs of getting the hole to the right size.

Sliced bread takes a back seat to a quality step drill bit! A quality step bit is not cheap!. An electrical supply house is the place to buy.
Tallguy and vegasloki like this.

65 C Code hardtop from California still wearing it's original paint.
Roller 331, TW 170 heads, T-5z, FiTech EFI, FPA Headers, Arvinode exhaust, SoT Bilstien coilover front suspension, TJ on eBay 8" 3.40 Trac-Loc 3rd member. Mustang Steve 2008 GT bracketed 12.4" front disks
Nailbender is offline  
post #9 of 23 (permalink) Old 06-18-2019, 10:52 PM
Senior Member
 
68Ghost's Avatar
 
Join Date: Mar 2017
Location: CT
Posts: 426
Yep, some good guidance here, go slow! Nice job Vegas, I’m jealous of that clean shock tower!

vegasloki likes this.

'68 Mustang Hardtop, 302, C4
AKA "Dr. Wolf"

68Ghost is offline  
post #10 of 23 (permalink) Old 06-19-2019, 01:17 AM
Senior Member
 
vegasloki's Avatar
 
Join Date: Nov 2017
Location: Vegas
Posts: 1,288
Thanks guys. The wells and underside were mostly covered in old oil, grease and kack. I'm pleased with original condition. I only wanted to clean that much because I want to drive it. A good soak with purple Zep degreaser, some Simple Green, elbow grease, the Krug Thug, Scotch Brite and it came out well. I finished that well with Krylon 1613 until I tackle refinishing the entire front under hood.

The stepper bit was surprisingly Harbor Freight. I've had it a while and this was the last two holes it did. Not bad. I'm looking at Amazon right now for the Greenlee set and yikes it's about $100 for the three piece. Quality costs.

If anything our posts can help convince/guide someone through doing the drop. It's nearly free and I'd say easily the most cost effective mod for the front end even if you don't change anything else.


67 Hardtop, brought it back to a driver
http://desertratretro.com
vegasloki is offline  
post #11 of 23 (permalink) Old 06-19-2019, 01:34 AM
Senior Member
 
Tallguy's Avatar
 
Join Date: Apr 2016
Location: NorCal
Posts: 788
I usually use a good sharp 1/8" bit to start a hole as easier to get the centers right, but then the step bit does the rest of the work. As others have mentioned, step bits are one of those tools that once you use it, you wonder where it has been all your life. Especially effective on thinner sheet metal where regular bits make a twisted mess on larger holes.
stephen_wilson and dobrostang like this.

66 Convertible. Full restoration in the works
Tallguy is offline  
post #12 of 23 (permalink) Old 06-19-2019, 01:56 AM
Senior Member
Supporting Member
 
supershifter2's Avatar
 
Join Date: Nov 2009
Location: Frum Hear Two Their Eventually
Posts: 10,754
I took a 3/16" thick steel plate and drilled 2 1/2" holes and 2 17/32" in it holes on the drill press. I bolted the plate to the factory holes with the 1/2" plate holes and drilled new 17/32" holes in the shock towers using the bottom holes in the plate. Checked them with short digital calipers. Elperfecto !
dennis111 likes this.

supershifter2™ < !
supershifter2 is online now  
post #13 of 23 (permalink) Old 06-19-2019, 06:04 AM
Senior Member
 
dobrostang's Avatar
 
Join Date: Oct 2009
Location: Upstate NY
Posts: 3,709
WHen I did mine, I dropped them straight down on my 66. I couldn't get any caster for years until I figured out my mistake. The next time I had my motor out I rat-tail filed the holes to the correct location then welded the other side, ground the welds flat and used the rat-tail to complete the holes. While I was at it, I welded up the old holes. Soooo, I pity the guy that gets my car in the estate sale, cause he is gonna think the Shelby drop was never done adn create a monster of a mess...
Russstang, 2nd 66 and 665spd like this.

Heavy Metal Thunder Video http://www.youtube.com/watch?v=cW3L_O7N_xs
dobrostang is offline  
post #14 of 23 (permalink) Old 06-19-2019, 06:18 AM
Senior Member
 
englishman's Avatar
 
Join Date: May 2017
Location: United Kingdom
Posts: 224
My homemade solution, shamelessly copied from an online template...
Attached Images
File Type: jpg IMG_0390.jpg (456.2 KB, 15 views)
File Type: jpg IMG_0391.jpg (421.3 KB, 15 views)
File Type: jpg IMG_0392.jpg (272.9 KB, 17 views)


1967 289 Coupe - AOD, Edelbrock heads, Victor Jr, EZ-Efi, roller front suspension, S197 front brakes, 3.55 gears
englishman is offline  
post #15 of 23 (permalink) Old 06-19-2019, 06:48 AM
Senior Member
 
dobrostang's Avatar
 
Join Date: Oct 2009
Location: Upstate NY
Posts: 3,709
Quote:
Originally Posted by englishman View Post
My homemade solution, shamelessly copied from an online template...
1/8" holes are the right answer!
2nd 66 likes this.

Heavy Metal Thunder Video http://www.youtube.com/watch?v=cW3L_O7N_xs
dobrostang is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome