The 3550 is a stronger transmission. And, seeing as you already have the the 3550, I would have them do the transmission tunnel.

 

The worse that needs to be done to the tunnel is to cut out the upper part of the tunnel reinforcement and clip a bit of the hole on the back right hand side. Make sure they don't butcher it.

 

PPrince, do have any more details on the required tunnel mods, pics, links etc?

 

Sorry, no I dont.

I installed my TKO600 which is the modern T3550. I cut the top part of the reinforcement and have about a finger of room around the tranny.

Do not allow any other notching of the shifter hole than the back edge to allow the shifter to shift. Many cut the front edge off to allow access to the shifter bolts. Don't let them do that and just access those bolts from underneath. You only need to do that once.

 

Hey guys – at pull away from a standing start. ….

Sounds like clutch chatter. While an extreme driveline angle could possibly cause this I would lean towards one of the following:

Bad motor/tranny mount.
Bad U-joints.
Really weak rear springs.
Slop in clutch linkage.
Bad pressure plate/clutch.
Warped/burned flywheel.
Wallowed out clutch pedal support bushings.
Loose/worn u-joints.
Worn yoke.
Bad tailshaft bushing.
Not enough yoke engagement on the tailshaft.

I know that you have addressed some of these but driveline vibrations due to drivetrain angle tend to happen while moving, not when starting up.

 

Things are a lot better than they were.
Problem occurs when pulling away from a standing start.
I basically have to keep the revs down and ease away gently.
There's no way I can give it gas and dump the clutch. I basically can't spin the rear tires as the drivetrain would vibrate.
There are no vibration problems at speed.

Is the consensus that it is not necessay to modify the trans tunnel to fit the 3550 other than possibly relieving the reinforcement and the gearlever opening?

 

I had the same clutch chatter problems as you did. I went through all the fixes and it never went completely away until I changed to a diaphragm clutch.

 

Is Centerforce a type of diaphragm clutch?

 

Centerforce has diaphragm clutches.

 

I agree with the clutch chatter part. You haven't told us yet what type of clutch linkage you have: Z bar, hydro, cable?

It also seems to me the 3550 might be overkill for your 302. To alleviate the dilemma of cutting your tunnel, have you considered just switching to a T5 and selling the 3550? No muss, no fuss with the T5.

 

"have you considered just switching to a T5 and selling the 3550? No muss, no fuss with the T5. "

That's where this thread started.

I've got the Z bar.

 

Ah yes, you're right. I got side tracked on the clutch chatter issue. I think you have two separate issues; they're mutually exclusive.

 

the 3550 is a great trans, but it's a bit on the notchy and heavy side, and has more parastic loss than the t5, along with a 2.90 or so first vs the t5's 3.35.

If you're making under 350-400 hp, you'll be just fine with a t5. If you don't mind cutting your tunnel though, I probably would go that route, as the 3550 will probably outlast the car itself

 

I have a 3550 that I took out of my fox body Mustang before I sold it. Make sure you want to use that 3550 before you install it. They are much more notchy than a T5 and they are significantly noisier than a T5. It's a strong transmission and it's hard to kill, but it's not very enjoyable to drive around with if you like cruising. FWIW, I'll be installing a T5 into my '65 Coupe, the 3550 will get tucked away in the garage for a rainy day.

 

i put a tko (same external size as a 3550) in a 69. with 1/2" drop mounts it resulted in an additional 0.25 to 0.50 degrees of engine angle over stock.

i put in a low profile shifter so i wouldn't have to cut the shifter opening. i had to notch the upper floor support and make a three inch cut to the tunnel for additional clearance. i made my own crossmember.

 

I just swapped to a T5 from an automatic, I'm on my second clutch and just installed a brand new flywheel from CJ's and the vibration / chatter got worse. I'm about ready to junk the car.

 

do you know the difference between vibration and chatter? Just asking...chatter is the skipping of the disc upon acceleration from a dead stop, either forward or in reverse.....the car shudders when moving from a dead stop. That's often caused by improper break-in periods. As well, certain clutches such as spec clutches are highly prone to chatter.

If it's vibration issues you are having, are you 100% sure they're related to the clutch? Does it do it in neutral at a stop? DId you use the right balance flywheel....50oz vs 28?

My brother had a "slight" vibration issue after we upgraded to a centerforce dual friction in his 01 mustang. We called centerforce and they gave a great explanation. Rather than go into extreme detail, the end result that you can do is to send your flywheel and clutch off as one unit(or find a local shop that can do it) and they can be balanced together as one unit. Once you balance your flywheel and clutch together as one unit, you don't get any vibrations from it.