[birdguy3]

289 stroked to 347 .040 over, edelbrock performer rpm cam, performer rpm intake, and performer rpm heads(1.90" intake), and 10:1 compression. If the T5 wont handle it, what are my options for a 5 speed that wont require major tranny tunnel mods? Do you have a good source for the tranny? I assume I need the 9" if the 8" wont hold. It will be street driven but the occasional trip to the strip isn't out of the question.
TIA

 

[Lemondrop]

Likely the T-5 would suffer failure , a Tremec is close to the size of a T-5 and quite a bit stronger . 8 inch is not a bad rear end but if your dumping $$ into a rear Id find a 9 inch to spend the dough on . No sense in building a 8 inch rear if your worried it won't hold abuse .

 

[camachinist]

Tremac and 9", if you want longevity. If running slicks and leaving hard at the track, you'll also want to look into enhancements for the 9" and consider switching to Spicer 1350 series u-joints along with a stronger driveshaft.

Manual trannies can be hard on parts but definitely are a fun ride...

 

[mrgem]

There are plenty of people who run T5s and 8s (behind big hp small blocks), but not if they want to run 'em hard and long. Your engine is probably putting out close to 400 hp (flywheel), I suspect. I've seen many a World Class T5 trashed by lesser-powered fox body cars.

Same story with the rear. Yes, you can build an 8 to take a bunch of abuse, but you'll spend almost as much as a 9 would cost. Remember, Ford wouldn't even put an 8 behind a 271 hp 289. They knew those cars would be driven hard and specified a 9 for that reason.

Forget what I say, though. Mr. Camachinist's opinion is the most valuable one you'll get here.

 

[kketell]

The T5 in most of it's variations will not do for that engine. The 8" could be made to work with lots of parts from places like Currie.

If you want a T5 that will stand up to your 347 you could contact the folk at G-Force Transmissions. They can rebuild one to stand up or build you a complete unit. They estimate their T5 to be good to about 600HP.

I just got my G-Force T5, but have not put it in the car yet. I'll let the collective know how things go when I get it all together.

 

[mrgem]

Kent - Looked at G-force's website and liked what they've done to their T-5s. They seem to address all the classic weak spots. However, I couldn't find anything at all regarding prices.

Are these gearboxes one of those "If you have to ask, you can't afford it..." items?

 

[Lightning]

G force gets $1950 for a transmission ready to bolt in!! Or $950 for the kit that you or a local tranny guy to install in your transmission, an extra $200 for them to do the install in your transmission.

 

[kketell]

You forgot the additional 150.00 per fork for the good shift forks. Doing the internals without doing the forks is kinda silly, IMHO.

I paid 2870.00 for a built transmission, including both forks and a Pro5.0 shifter, delivered to my door. This should be the last transmission I ever have to buy for this car, unless I decide I need six speeds, which is unlikely.

 

[LMan]

I would wait for the 8 inch to break, if it does, before I swap out something I may not need. To be honest, I ve heard of plenty of T5s snapping but Ive never actually seen documented evidence of a decent 8 inch rear snapped by too much HP/torque. Not to say they arent there, but I find it odd Ive never seen one (even on the Net, other than rumor control). My FIL drag raced a Comet Cyclone in Stock and Super Stock , manual xsmn, for more than 7 years in the Southeast and never broke his 8inch rear. Went thru some motors and a T10 or two though :: YMMV

 

[Stroked66]

I too am considering the G-Force Trans or internals for sometime down the road.

Chances are you wont "Break" a 8" T-Lock, but the week link will be the clutch packs, which you will end up toasting if you plan to be agressive with it. In which case, a 9" Locker would be agood choice (Even a 9" T-Lock is questionable). But it's all about how you plan to use the car. Lockers arent for everyone.