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Should I swap my t5 out while the engine's out? Or just see if it lasts?

  • Thread starter Thread starter SadbutTrue
  • Start date Start date Apr 14, 2008

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
Apr 14, 2008
#1
  • Apr 14, 2008
  • #1
I’m planning (as I’ve repeated to people at least 100 times on this forum in the last few months… I swear it’ll happen and I’ll stop talking about it soon!) on swapping new heads/cam/intake on to my 351, expecting it to push 425 hp/tq (351w, 9.5:1, Trick Flow TW heads, Stealth, compcams 274xe… the same combo but with a roller 331 made 438 hp in a magazine article.. its on AFR’s site..).

I have a t5 in my car now out of an 89 GT. It works great now. However, I have my doubts as to how it’ll handle the engine. That’s basically the question… while my engine is out at the shop is the easiest time to swap in a new transmission (and pull the current one while its worth something, whereas if I break it…). Should I do this? Tony at Astro transmissions says his super-alloy t5 (essentially a T-5z) will be fine for the aforementioned application, and that real high-end T-5s (gforce, A-5, etc) are overkill.

There are a number of factors that might help my current T-5 live a lot longer than it would in most cars. My 66 is really light. I have relatively tame rear gears (3.25). I do not plan on running drag radials or slicks (though I may put cal-tracs on it to reduce wheelhop… I hate wheelhop with a passion). I don’t race the car (the nearest track is 2 hours away, and is LACR… which sucks). I don’t powershift the thing or drop the clutch at 3k rpms. Its abuse will be limited to things like spirited country road driving, having fun on highway onramps, etc.

So yeah… what would stangnet do? A new T-5z is about 1500 shipped from summit (if anyone knows anyplace cheaper please let me know), and I figure I could still get 500 for my T-5, so a total outlay of roughly $1,000.
 
6

68EFIvert

Member
Jan 13, 2007
639
0
17
Camas, Washington
Apr 14, 2008
#2
  • Apr 14, 2008
  • #2
I have a blown 302 with a little over 400 rwhp and I have been advised that my 1988 T5 should be fine. I plan on driving my car a similiar way that you plan on driving yours. I will replace mine with a TKO 600 or T56 (if gas prices continue to go the way they have) if I have problems down the line.

There is a guy in my club that is running an 88 Fox mustang with the stock tranny. He is putting out about 450 rwhp without any problems. I think a lot of it comes down to how hard you drive your car.
 

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
Apr 14, 2008
#3
  • Apr 14, 2008
  • #3
68EFIvert said:
I have a blown 302 with a little over 400 rwhp and I have been advised that my 1988 T5 should be fine. I plan on driving my car a similiar way that you plan on driving yours. I will replace mine with a TKO 600 or T56 (if gas prices continue to go the way they have) if I have problems down the line.

There is a guy in my club that is running an 88 Fox mustang with the stock tranny. He is putting out about 450 rwhp without any problems. I think a lot of it comes down to how hard you drive your car.
Click to expand...

Your last point is another thing Ive thought about. There are tens of thousands of hot 5.0/fox body mustangs out there and I highly doubt they ALL go out and upgrade their transmissions (Tremec would be a fortune 500 company if they did).

Maybe we could have a pool and see whose lasts longer...
 

88gt

Founding Member
Aug 2, 1999
794
0
0
Drillers cabin
Apr 14, 2008
#4
  • Apr 14, 2008
  • #4
You could have your t-5 rebuilt to t-5z specs for under $500.00 and be just fine. When I rebuilt my t-5 I added the cobra tapered bearing/alloy lower gear set and had more tranny than my basically stock 302 could handle.

Do some research on the cobra input shaft tapered bearing...can be done, if anybody says no..they're yanking you around...
 

mrmustangman357

Member
Feb 11, 2007
763
3
18
Apr 14, 2008
#5
  • Apr 14, 2008
  • #5
LACR closed last year, no?
 

red65

Member
Apr 12, 2003
411
0
17
Ann Arbor, MI
Apr 14, 2008
#6
  • Apr 14, 2008
  • #6
SadbutTrue said:
Maybe we could have a pool and see whose lasts longer...
Click to expand...

The Cobra T-5 I had in my '65 behind a blown 306 making 445rwhp lasted about 2-years. That's more than I'd originally expected. In that time, it never saw a drag strip, ran on street radials, and did maybe 8-10 open track events. One day on the street (not on a track), while shifting into third (spirited, but not abusive), it clanked loudly and then was no more. The insides looked like a grenade had gone off - hard to tell what failed first.

It's not a matter of "if" in the 400rwhp+ range, it's "when."
 

iskwezm

10 Year Member
May 24, 2005
4,159
20
79
Rowland Heights,California
Apr 14, 2008
#7
  • Apr 14, 2008
  • #7
mrmustangman357 said:
LACR closed last year, no?
Click to expand...
yes, but that track was a dusty accident waiting to happen
 
D

D.Hearne

New Member
Sep 29, 2000
11,730
6
0
south louisiana
Apr 14, 2008
#8
  • Apr 14, 2008
  • #8
Just a little "salt in the wound" but I wonder how much longer the 40 year old Toploader in my Ranger will last ? As far as I know, it's never been rebuilt, other than the blocker rings being changed. My son sold his 94 GT Stang to his freind two years ago and it's T5 has never been touched and both my kid and his friend has put that one through hell. It's amased me it's lasted this long. The car has well over 100K miles on it.
 
6

68EFIvert

Member
Jan 13, 2007
639
0
17
Camas, Washington
Apr 14, 2008
#9
  • Apr 14, 2008
  • #9
SadbutTrue said:
Your last point is another thing Ive thought about. There are tens of thousands of hot 5.0/fox body mustangs out there and I highly doubt they ALL go out and upgrade their transmissions (Tremec would be a fortune 500 company if they did).

Maybe we could have a pool and see whose lasts longer...
Click to expand...


It may be more fun to see who can blow their tranny up first.
 

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
Apr 14, 2008
#10
  • Apr 14, 2008
  • #10
68EFIvert said:
It may be more fun to see who can blow their tranny up first.
Click to expand...

Sounds like Red65 already won that one though But why not.. how much of a head start do you have on me?

Originally Posted by mrmustangman357
LACR closed last year, no?
Click to expand...

Well, thats just awful. Not sure what I'll miss more, the absolutely awful track surface, the altitude that added half a second to your ETs, or the fact that its in the middle of nowhere...

And I don't think I'll have 400+ rwhp. Probably more like 350. I know...
 
6

68EFIvert

Member
Jan 13, 2007
639
0
17
Camas, Washington
Apr 14, 2008
#11
  • Apr 14, 2008
  • #11
SadbutTrue said:
Sounds like Red65 already won that one though But why not.. how much of a head start do you have on me?
Click to expand...

My car is still in the body shop and will likely be for at least another month. I will then reassemble so I am likely 2 months away. You can have the head start. If it breaks before I get running let me know and I will sell mine and go get a TKO 600.
 

CraigMBA

New Member
Mar 24, 2007
783
1
0
Orange, CA
Apr 14, 2008
#12
  • Apr 14, 2008
  • #12
You won't break it on street tires if you don't bang shifts like an idiot.

An aftermarket shifter w/ stops will go a long way from bending the shift forks and hanging it between gears.
 

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
Apr 14, 2008
#13
  • Apr 14, 2008
  • #13
CraigMBA said:
You won't break it on street tires if you don't bang shifts like an idiot.

An aftermarket shifter w/ stops will go a long way from bending the shift forks and hanging it between gears.
Click to expand...

I have the pro 5.0, so hopefully that'll help. wasn't really sure on how to set the stops, just sorta checked to see how much room i needed to shift and set the stop screws right up against that with a few paper widths of clearance...
 

red65

Member
Apr 12, 2003
411
0
17
Ann Arbor, MI
Apr 15, 2008
#14
  • Apr 15, 2008
  • #14
CraigMBA said:
You won't break it on street tires if you don't bang shifts like an idiot.
Click to expand...

I've been called worse.
 
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