Steering box question

[jscott]

While my car is still new to me and unknown if I need it (car goes into shop for a review by a mechanic this week) I saw a power steering box on fleabay and picked it up.   It was sold as a SPA-S but came in tagged SPA-AF.     What is the difference and which is better?  My car is a '72 fastback w/power steering

 

[c9zx]

The variable box is generally preferred. https://www.7173mustangs.com/thread-anyone-replace-their-power-steering-gear-box   Chuck

 

[Bentworker]

SPA-AF tag means it is variable ratio.

It is the better of the two boxes.

The variable box will be a little “quicker”

 

[Hemikiller]

Easy way to tell which box you have, regardless of the tag.

Standard ratio power box - 4 turns lock to lock

Variable ratio power box - 3 1/8 turns

Boat, er manual - 4.5 turns

IMO, the variable ratio is the only way to fly.

 

[Stanglover]

Easy way to tell which box you have, regardless of the tag. 

Standard ratio power box - 4 turns lock to lock

Variable ratio power box - 3 1/8 turns

Boat, er manual - 4.5 turns

IMO, the variable ratio is the only way to fly.

Agreed.

I thought about doing a 12.7:1 fast ratio , but for the pita to get correct and decent parts or pay someone through the nose to buy one, why bother for oriinary street driving.

 

[guys72Mach1]

Funny, was just going to post something about this. My 72 Mach 1 gear boxes is going out and getting hard spots, so I've been looking at the options out there. 

The best performance options based on reviews and comments, looks to be $450+, via powersteering.com. Gotta pay for R/T shipping, then wait 3 weeks to get it back. But, that 12.7:1 steering sounds like the golden ticket. My car is built for protouring, so I'm leaning this way, plus I can use my existing hoses, which now that I put that in writing, they'll prob start leaking!   

But man, that $5 hundy is a chunk and shipping(and waiting) is a pain.. 

Decisions decisions

 

[EdM]

I have a power steering dot com 12.7 in my car and it is perfection. When I bought the original owner was selling the business so I paid a fair bit less than what they are asking today. That with Shaun's coil over system is pure bliss.

 

[machattack]

SPA-AF tag means it is variable ratio.

It is the better of the two boxes.

The variable box will be a little “quicker”

Do you know what the regular box tag says? curious when I check mine as to what I got. To have them Rebuilt costs a small fortune.

 

[Hemikiller]

Constant ratio: SPA-S, U, AC OR AE

Variable Ratio: SPA-T, V, AD OR AF

 

[machattack]

Constant ratio: SPA-S, U, AC OR AE

Variable Ratio: SPA-T, V, AD OR AF

Thanks a lot sir! for taking the time to help me and others.

I hope I got the variable ratio? Dont get the car back from blasting til next weekend, Ill check then. You folks got some button you push to get all these answers? dang nabit you fellers are smart

:thankyouyellow: