Looking for mod options for newly acquired '66 Mustang Fastback

395GIRL

New Member
Oct 19, 2020
3
0
1
63
California
Just inherited my Dad's '66 Mustang Fastback. Survivor car, numbers matching, and complete. C code 289 w/3 speed manual trans. Body and interior near mint. Motor out and disassembled. Thinking I want a fun car to drive on weekends. What performance mods would be best?
 
  • Sponsors(?)


rbohm

SN Certified Technician
Apr 12, 2002
6,698
550
204
62
tucson,az
ok first stiffen up the chassis. subframe connectors, export brace, monte carlo bar, zray crossmember, add in torque boxes, add in stringers to tie the subframe connectors to the inner rocker panels, add in also the cross support that ties the two sides together into one rigid structure. remember the stiffer the chassis the more effective any suspension modifications will be.

suspension mods, the shelby drop costs nothing and templates are available from a variety of sources, dazecars has the template in steel and he also has teh proper drill bit to get the holes sizes right. koni shocks on all four corners, proper springs front and rear. which ones you choose are up to you. and you will get lots of advice for choosing. run a 1"" or 1 1/8'' front bar, no rear bar, or a 5/8' rear at the largest.

engine mods, good heads, i have teh windsor jr heads in cast iron as they were the best at the time, but there are plenty of aluminum heads available these days and all are good. intake i prefer the edelbrock performer rpm with eitheran EFI set up on it or a 1406 edebrock performer carb, its 600 cfm and a damned good carb. for a cam again that depends, i got a retrofit roller cam from comp cams with the 351w firing order, but there are many good flat tappet grinds available as well, choose wisely. for headers i like the tri-y design, they fit well and shelby used them to great effect in the 60s when racing.

wheels, tires, brakes. i like the factory kelsy--hayes four piston calipers with factory rotors. they flat work. in the rear you can go with disc brakes from the aftermarket or use the F150 11x2 /14 rear drums, better tham what shelby used on the GT350s. wheels and tires are personal choice, but i plan on using a 15x7 steel wheel with either a 205/65 or 215/60 15 tire.

for a driveline, i plan on using 3.55 rear gears in an 8"' rear end and a C4 trans. what you decide is up to you as well.
 

Jimchil

New Member
Oct 19, 2020
4
0
1
63
Los Angeles
Just inherited my Dad's '66 Mustang Fastback. Survivor car, numbers matching, and complete. C code 289 w/3 speed manual trans. Body and interior near mint. Motor out and disassembled. Thinking I want a fun car to drive on weekends. What performance mods would be best?
I would just like to mention the changes that made the most improvement in my 65 fastback. Stiffer springs, extra duty shocks such as Bilstein to handle the springs, t-5 conversion, balanced well-put together shortblock, tri-y headers, petronix ignition, Toyota Corolla seats (yeah, but no more sliding around. And headrests. Fits me like a glove), Shelby front valance and trunk tail spoiler, disk conversion for stopping straight, fat radiator, side mirrors I can see out of, fat front sway bar, 3:55 posi, will have electric windows.
 

wicked93gs

10 Year Member
Sep 30, 2006
948
113
73
Nashville TN
Honestly, I am not sure I would tear into a fastback without thinking about it first...they are only going up in value. No one cares if you cut up a T code coupe...but it can significantly affect the value of a fastback. That being said...not sure what you mean by "fun" where you begin depends on whether you want fun in a straight line or around the corners...they aren't mutually exclusive, but it will significantly affect which modifications you do.
 

rbohm

SN Certified Technician
Apr 12, 2002
6,698
550
204
62
tucson,az
That's a lot of information! Thank you for putting that together. Lots of research and decisions to make!

the very first thing you need to do is sit down and make a plan on what you want from this car, and what direction you want to mod the car. then set a budget, start with what parts and labor are going to cost then triple that budget and you are good to go. once you start, stick with the plan, that way you get things done faster overall, and you dont get sidetracked with the latest whiz bang idea that sounds good but may not be for you.

Honestly, I am not sure I would tear into a fastback without thinking about it first...they are only going up in value. No one cares if you cut up a T code coupe...but it can significantly affect the value of a fastback. That being said...not sure what you mean by "fun" where you begin depends on whether you want fun in a straight line or around the corners...they aren't mutually exclusive, but it will significantly affect which modifications you do.

i agree. when you decide to modify the car, try to make sure that every modification can be fairly easily reversed by the next owner. for instance, i would avoid putting on huge fender flares(happened often in the 70s) because they are very difficult to get rid of. keep your mods to unseen areas, and bolt on changes as much as possible.

one more thing, when you start the project, focus on ONE area at a time. and start at the beginning, the chassis. you need a solid foundation to build upon, otherwise you are throwing away good money on junk.

the other thing is dont be afraid to ask questions BEFORE doing something questionable. better to ask stupid questions than make irreversible stupid mistakes. and this means asking questions here, and/or calling the experts to get good advice. for instance when you get around to the engine, and are at the point of selecting a new cam, from here you will get a ton of good choices to make, as everyone thinks their combination is right for you, whether or not it is. so call the cam manufacturers as well and get their input and recommendations for a com for your combination.

if you ask me about cam selection, i will start off telling you how to select a cam, rather than just give you a recommendation so you t least know the process, but we can save that for later.
 
Last edited:
  • Like
Reactions: Name Goes Here