I've been doing some research online, you guys seems knowledgeable, so I thought I'd post here.

I'm currently working on a 1967 Cougar, for which I bought a 2014 5.0 and 6spd transmission from a wrecked GT.

I don't know a lot about rear ends and gear ratios. I do know that my stock 8" is not going to cut it.

I'm ordering a 9" from a place in Ames IA, and one thing I have to decide is what gear ratio to use. I believe the stock '14 GT auto uses a 3:15.

This is just going to be a driver car. No drag racing, and I like to drive 80 on the highway. Should I stick with the 3:15, or should I do something different? I'm planning to just try to match the tire diameter to what's on the mustang, if that helps.

Appreciate any advice...

 

Stock GT's are 3.55's, how much does the Cougar weigh? I would say you could keep the stock rear gear size if the car weighs a few hundred pounds lighter.

 

Sounds like you got a 6 speed auto from the wrecked GT?

If so, I'd probably stick with something like 3.15s. Cougar has smaller wheel wells and such, so you're probably gonna end up with a shorter tire than a stock '14 Mustang. This would give you a little more gear than a stock mustang, but still be good for highway cruising.

I love 67-68 cougars, cool to see someone doing a coyote swap. Are you doing the TCI front suspension setup?

 

Have you considered just using the differential from the wrecked GT? Assuming it is still usable. Instant disc brake conversion at that point too... Might be able to use lots of components with some modification like the Gauges and what not also. Food for thought. Will be a awesome project! Good Luck!

 

Shipping weight for Cougar was 3005lbs, compared to 3618lbs for the mustang.

 

Thanks for the input! Appreciate the feedback, especially cause I know technically I'm probably not supposed to be posting about a 67 cougar in a 2014 mustang forum.

I did do the TCI front end, which was a requirement because no way was this engine fitting in there with the factory shock towers. Now just have to nail down the 9" rear and get that and the 4-link rear ordered.

Unfortunately all I got from the GT was the engine/trans/shifter/pedal/engine harness, and the nav/radio. I wish I could have gotten more but I want to stick the budget as much as possible - and also stay married.

The 9" rear I'm ordering does come with disc brake kit on it, and the front end has already been converted with the TCI kit.

 

you could also just buy beefier axles for the 8" and not have to go through the hassle of fitting a new axle housing back there

IIRC... as long as the bearings are the same, you can put 9" axles into the 8" housing. Plus there are tons of options for tracloc, spools etc..

the 8" is more competent than people realize and also lighter than a 9".

Either way good luck with the swap. It sounds like you've got an awesome project. Please post some pics if you have the chance

 

I've found mixed info on using the 8" and beefing it up. I started down this route, but talking to the guys at Curry Enterprises stopped me. Replacing the gears and axles would end up costing me almost as much as just buying the 9", which is fine. But they told me that the power coming out of the Coyote WILL tear it up, it's only a matter of time.

On the other side though, I've read a lot of forums where people are putting 600hp through a beefed up 8". I just want to make sure whatever I do, I only have to do it once.

I'll definitely get some pictures up ASAP. The engine is almost in the car!

 

cool, I just wanted to make sure you knew about the options before you went any one route. I plan on eventually building up the 8" in my II, unless I somehow acquire an IRS and all the fabrication tools/skills necessary to install it lol. Either way though, I don't plan on really making that car overly powerful.

can't wait to see it!

 

Can't wait, sounds like this thing is gonna be badass!

 

OP, if you haven't already check out ModularFords, they have a great swap section, at least it was when doing a termy swap.

 

OP, please post pics of this project! I love modern day swaps!

 

Thanks Brandon302, I'll check that out.

First pics attached, engine is in the car! http://imgur.com/mW4Wgsi

 

[QUOTE=southfanning;6712030]Thanks Brandon302, I'll check that out.

First pics attached, engine is in the car!

 

It looks right at home in there

 

That's going to be a fun ride, with 600lbs less it going move right along.

 

Love this! I can't wait to do my Coyote swap into my '03 GT!

 

Looks like it wouldn't have been possible to fit it in there if the stock shock towers had still been there.

 

Oh, no chance it would have fit. The shop tried it in stock 67 mustang just to see, they said it was nowhere close to fitting. I originally removed the shock towers to put in a 4.6L, and that 4.6 looks like a baby compared to the coyote. This thing is a beast!

 

That is going to be SO awesome when finished!
Yeah, 600lbs lighter... Wow.