[bluerestomod]

Hello to all. I have a 66 notchback that I am finally beginning to work on. I have owned it since 02/03. I am converting the C4 to the T5 with a 306 roller. I just purchased a t5 for $200. It was out of a 86 asc mclaren with 64k. The seller couldn't get the number off the tag. I met the seller and decided to purchase the t5. Once home, I took a wire brush and cleaned the tag and was able to read the numbers. It was a 1352-126, 85 Capri WC 5.0. 3.335 1st, 1.93 2nd, 1.29 3rd, 1.00 4th, and .80 5th.

There is not much info that I could find about the unit because of the 3.35 and .80 5th. Any insight would be helpful.

What gearing would you recommend for the 8 in? Would I be better of with a 3.40 or 3.55?

The engine is a 306 roller with a xe274hr cam, edelbrock air gap intake, holley 650dp and aluminum heads(im looking at a set of brodix st 5.0r).

Thanks in advance

 

[awhtx]

The .80 5th gear makes it more like a 5 speed than a 4 speed with OD. The typical T5 has a .63 OD which is a huge drop from 1.0 4th gear.
I have a T5 with the 2.95 1st gear and the .80 5th gear in my '65.

 

[Mike the old grump]

What gears are currently in it?

I have a car with 3.28:1 1st and 1:1 5th. The rear end gears are 3.55 and it's geared too low. The car would be happier with 3.08s in the rear. 1st is pretty much useless. I rarely use 1st gear.

I would figure out what gears they used in the 86 ASC Mclaren and use that as a guide.

 

[Nos681]

According to this information it has a different 5th gear ratio, if stock.

 

[j persons]

The .80 5th gear makes it more like a 5 speed than a 4 speed with OD. The typical T5 has a .63 OD which is a huge drop from 1.0 4th gear.
I have a T5 with the 2.95 1st gear and the .80 5th gear in my '65.

I had these ratios in a T5 built by Levy Racing in my FFR Cobra, along with a 3.55 rear ratio. This car was a blast to drive. The gear spacing felt almost like what you would get in a sport bike LevyRacing Super Alloy T5 Gear Box — LR Classics LLC

 

[67Modcoupe]

I have a WC T5 with roller 306, similar head/cam/intake to yours, and am running a 9" with 3.70s. The T5 I have has the typical .63 OD which makes it work great with the 3.70s on the freeway. But 1st and 2nd are pretty short. I basically can get to 61 or 62 MPH at ~6000 RPM in 2nd before grabbing 3rd. The gearing makes the car feel like it has 100 more HP than it does. It spins through 1st and 2nd at WOT. I think it would actually be quicker if I went to, say, a 3.25 rear. I'd suggest somewhere around a 3.25 - 3.50 for your engine combo and that T5 gearing. Good luck!

 

[2nd 66]

I'm running a 3.35/.68 T5 with a 3.40 TL 8" anything much more would make 1st gear totally useless

 

[bikefreak600]

3.70 are perfect gears for a mix of highway cruise and performance. It also allows you to run a taller or shorter tire without drastically effecting comfort.

 

[1ofAMillion+]

I have a fair skepticism of all things British but this has different info.
Identification Key to Borg-Warner T5 transmission ID Tags

I have *-238 which has a .72 OD/3:00 revs to make pulling torque again about 75MPH for passing

View attachment 770059

According to this information it has a different 5th gear ratio, if stock.