tremec tr3550

[Wally68]

Good morning every one .
I'm a first time user of this forum.
I'm in the very early stages of building a G-force cobra,infact I dont have the kit yet but what I'm doing is getting some parts together.
I' going to run a 302 windsor ,and I have a powr-lok 2.88-1 diff,and will run approx 25'' dia wheels ,now my question is
(1)I have a option to buy a tremec 3550 gearbox.is this a good box
(2)Dose it fit into the car well ie(enough distance between diff and gear box for tail shaft to fit in and gear shifter location)
(3)Is $2000 for a new TR3550 a good price.
(4)Will the gearing be ok

Thanks in advanced

Dave

[rblong]

I used a 3550 for 10,000 miles with no problem on a 400 hp BB.

Don't now where your at but Classic Transmission in Fort Worth is best price I found. You can pick up good used 3550s cheap. I have one in the shop I would sell for $500.

Don't know about fit. It fit my Lone Star Classics.

Your HP is gonna have a lot to do with gearing. 2.88 looks a little low to me unless you run LOTS of hp. I run 3.25 rear with 25.7 tires with well over 400 RWHP. Play with this calculator http://www.secondstrike.com/technical/gearcalc.asp

This site also has a lot of good info. http://www.5speedtransmissions.com/index.html

Hope this helps
Bruce

[400TT]

My brother runs a Tremec 3550 in the black Harrison. Was running with only 230rwhp, but has been putting 330rwhp through it for last 6 months.

The car is circuit raced every few weeks or so. The car is drag raced monthly/bi-monthly. And street driven.

3550 has been rebuilt once and will require rebuilding every couple of years or earlier for this sort of use/abuse.

Personally I think the T5 is a better shifting box, smaller, lighter, quieter, less power loss...but with 3550 you would never have to worry as much about the abuse you give it. Anything stronger would be overkill unless your thinking some serious forced induction. T5's are normally rated around 300ft, where as 3550 is 425ft. Just make sure you get world series T5.

T5 is much smaller and would be an easier fit. Not familiar with the G-Force, but shifter location will be fine. Tail shaft will be fine. The only problem you will have is clearance in the tunnel for rear part of the gearbox housing. We had to remove the strengthening ribs to get enough clearance in Harrison, but we moved the engine back a lot further than usual. I seriously doubt it's going to be a problem.

Here are the ratios:

TR-3550 3.27 1.97 1.34 1.00 0.68
(.68 5th makes for a perfect cruise gear, not useful for track use).

3550 was designed as a replacement for T5's, so ratio's are comparable and quite good for the street.

Also TKO & TKOII versions of 3550. Ratios are the same, just some improvements & extra power handling 525ft.

That rear end gearing looks a little tall to me, but see how it drives. If you want a cruiser, then it will drive fine. I expect it will still be able to handle slow corners in 2nd gear. If you want it to faster and more tractable off the line etc you will be heading for 3.5 -> 3.9 with 26" diam. rears. As you start moving away from a stock engine and losing your bottom end driveability, you will need lower gearing(3.5+).

The later TKO 500/600 are available with taller 1st gears and more even spread of ratios and lower overdrive ratio.

$2000 for a new 3550 here in Aus sounds like a bargain to me, I would snap it up. T5's used to be cheap, but are getting harder/more expensive to find now.

[Wally68]

Thanks very much for the info craig.
I will look at buying this box if its still available.

[Plums]

Good to see another G-force builder on here, and in Perth too... excellent!!!

[Aussie Mike]

He probably won't talk to you Bobby. You being a dark sider and all

Cheers

[Andrew429]

Hi Dave,

It looks like alot of this has been said already, but here goes.
A 3550 will be fine behind a 302.
The gearing will be better suited to a slightly shorter diff ratio, however if it's going to be used for cruising I wouldn't get stressed about it.
The fit will be easy as this used to be a common box in these kits. I've got a TKO (identical outside dimensions) that is essentially the same except for some upgraded bits - this fits without mods.
$2000 sounds like good value, A TKO goes for around $3700 - $4000.
Hope this helps.

Cheers

Andrew

[Wally68]

Is that Bobby that almost got to the cobra meeting last week?

Dave

[Plums]

Yes that was me. I just went to join up and pay my my fees, then I had to get back to work.

[Wally68]

It was my first night out there,Have not joined yet but will do soon.
It was good to talk to people that have been there done that,spoke to your mate Paul,he said he gets his kit in the next couple of weeks.
Its all good Fun.

Might see ya at the next meeting.

Dave