Drivetrain T56 Magnum Install '89 Fox

CHILL347

I could barely beat on it while driving.
Oct 27, 2019
24
23
13
Beaumont, Ab
Hey everyone. New to the forum but not new to the Fox Body world. Not an expert either by any means. I've had my '89 notch since 2005. I figured I'd share my experience with my recent T56 Magnum install. Bought the close ratio version as a kit in the spring that came with everything I needed except for a driveshaft. My engine is an R block 347 with AFR 185 heads NA. Dyno'd @370/362whp/tq. So nothing crazy but definitely too much for the infamous T5 the way I like to shift. (That's what it made with the stock A9L computer and SCT chip. I now have a MSPNP2 and am still currently tuning it)

Parts:
-Tremec T56 Magnum Close Ratio
-McLeod RST Dual Disc Clutch
-QuickTime SFI Bell Housing
-Ford Racing 31 Spline Driveshaft Yoke
-SN95 Clutch Fork (had to modify for my application)
-Couple of pigtails for the reverse light switch and reverse lockout solenoid
-Stifflers Transmission Crossmember


I run BBK long tube headers which made the install a bit of a pain in butt. In order to even get the Bell Housing installed I had to unbolt both headers. Then came the test fitting. This involved bolting the transmission in a few times to see what needed to be modified. I had to trim one of the tabs on the passenger side of the trans housing. I had to massage the trans tunnel where the shifter base sits. I had to trim about an inch off the clutch fork and modify the hole for the cable. I had to massage the driver side header for clutch fork and cable clearance. I had to adjust my adjustable clutch fork pivot ball which is recommended to use with dual disc clutches as they are thicker. Then I had to measure my driveshaft and see how much needed to come off. I took it to a driveline shop where I had them shorten my driveshaft by exactly 3 inches and install the 31 spline yoke. Once it was finally all installed I had to do a small amount of wiring. I had to wire in the reverse light switch as well as the reverse lockout solenoid. The reverse lockout solenoid I wired into my LineLock/2 step button on my shifter. Some wire it into the brake pedal switch but to me I already had a switch readily available and easy to tie into close by.

It was a successful summer with the new transmission and clutch. Clutch feels great, light and very smooth. The transmission feels great too and it feels cool driving a 6 speed Fox. I ran Redline synthetic ATF at first and then I ordered Tremec Transmission oil right from Tremec to replace the Redline after breaking it in.

The factory speedo cable also reaches and works for the T56 Magnum install. All I had to do was adjust where it was clamped on the firewall to get extra length.

 
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Nice work man! Looks great! Those long tubes sure make things tight under there, that's for sure. Glad it's working good for you. High quality stuff no questio

Welcome to stangnet! This is the best forum I've found for fox body stangs for sure. Lots of knowledgable and good folks here.
 
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Excellent write up Chill347.

I also just did the T5 to T56 Magnum swap. My kit was from D and D Performance. Came with Quicktime Bellhousing, driveshaft, crossmember, speedometer cable, shifter and the close ratio like yours.

I had the same problem with long tube headers trying to be in the same space as the release fork. I used a McLeod hydraulic release to resolve.

No floor or shifter hole clearance required but I had to cut off the same ear off the passenger side. When the cut piece fell to the floor and I saw a green paint line right where I cut and an X on the offending piece. I figured it was marked to cut but nobody cut it.
 
There are heavier & more moving parts in a T56. Some people say it makes a BIG difference, but I don't believe that either. Any chance you'll get it re-dyno'd with no other changes?
 
There are heavier & more moving parts in a T56. Some people say it makes a BIG difference, but I don't believe that either. Any chance you'll get it re-dyno'd with no other changes?

Not sure yet. Now that I am running a MegaSquirt I kinda want to have it dyno'd again once I get the tune all dialled in. But that is going to have to wait till next year some time or even the year after.
 
Did you dyno with the T5 with an otherwise as is combo? I would really love to see the impact the trans swap had on rwhp.

Did not dyno with either but what difference would it make. The T5 is too small for a powerful engine. So even if there is a slight advantage in efficiency, it equals nothing of value when it's broken.

The ONLY time I would tempt with a fragile T5 over a T56 is for maybe a class race where a say 5% loss in efficiency will cost you a race.
 
@CHILL347
Well, that implies a change to the tune which may throw off the results. I'm just curious, because I've got to T56 in both of my cars, and I've seen posts that give, in my opinion, outrageous differences in dyno output that I do not beleive (30+ rwhp in an N/A car if memory serves). It's in that other mustang website's fox forum.
 
Astro or G-force T5 = more torque capacity but less power consumption. A certain regular on this site is considering the options. I would personally go T56, as I have in both of my cars with a spare on my garage floor. However, the power difference is certainly good reason to avoid a T5 if the only evidence I can find is to be taken seriously. I don't believe it but have yet to see direct power measurements disproving it.
 

Of course it implies a change to the tune hopefully for the better. I certainly wouldn't waste my money throwing it on a dyno just because I swapped transmissions but also the tune on the stock computer was so bad that I wouldn't want to have it run up on a dyno. 30 whp seems outrageous. I could see a few but I doubt 30.
 
If you need tips on that tune let me know, if nothing else I can sanity check for you.
 
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That's exactly why I'm so interested in seeing direct results without any changes. Here's from that other forum:

 
And that's how I feel, but I have yet to ever see an apples to apples comparison. People rarely just do a T56 swap and call it a day.

Well I sorta did, that was my big modification for this last season. But like I said, the tune wasn't trust worthy enough that I'd stick it on a dyno and risk hurting it. I could barely beat on it while driving.
 
Who cares about a dyno number. We only use it to tune. Say the T5 is more efficient but it's slower at the track due to wide gear. What good is this information?

We all modify for different reasons. T56 shifts better, T5 is cheaper, T5 is great for wide power bands, T56 will handle way more power, T5 is unreliable etc.

So even if there was, and probably is a slight loss. The T5 and T56 Magnum close ratio have very different gear ratios. So a back to back comparison is not realistic. Some engines hate the big rpm drop between gears, some don't care.