T-5 vs. Toploader 4 spd - how to choose

[cardude]

Hey anyone got good insight or opinion on which option would be a better choice.

I currently have a hot 289 with the 3 speed attached to it. the 3 speed is a great tranny but at 60MPH my engine is winding at 3.5K. I know I need to check the gearing in the rear (bough it with home grown front disk and rear axle conversion so I am not sure of the gearing). but as I build it up I am looking at either dropping in a 4spd top loader (should be more of a drop in and go deal), or do a full conversion to a t-5. Any suggestions on what route to take and if there is a great difference between the two worth the added expenses.

also any good quick tests to get an aproximation of the gear ratio?

thanks

 

[3spd on floor]

well the 3 and 4 speed will both have the same top gear ratio, 1:1. So if you're looking to drop the revs down you will either need to change your rear gears, or the T5. What do you mean by hot 289? the toploader can hold GOBS more power than the T5...

 

[SadbutTrue]

well, based on your post the answer is simple: T5. The T5 has overdrive, the toploader does not. Your top gear rpm will not change with a toploader.

What do you call a "hot" 289?

 

[6Stang7]

I thought that there were some 4 speeds that had an overdrive gear. How common one is I donno, but if you want an OD gear, then your best bet is a T-5.

-Shaun

 

[Pakrat]

How you use the car should be part of your decision. If it is mainly a cruiser that sees only occasional highway driving, then with original 2:79:1 gears, your 3spd would actually be fine most likey. If you are just looking to upgrade your 3spd, then going to a 4 is like switching from single points to dual points. Sure it is an upgrade, and at one time it was the best, but not necessarily anymore. Stay ahead of the curve and go witht the 5 speed just as it would be better to go from single points to a pertronix or other electronic ingnition instead of a dual system.

Now if your engine is really hot and you are looking to take it even further in the future and plan to launch quick and do some quarter mile runs, then the 4 spd may prove more suited to the task.

How do you plan to use the car and how hot is hot?

 

[Edbert]

I thought that there were some 4 speeds that had an overdrive gear. How common one is I donno, but if you want an OD gear, then your best bet is a T-5.

I believe those OD 4-speed manuals were in trucks and Broncos.

If you want to lower your RPMs while cruising get the T5.

If you are pushing 400 or more HP at the flywheel then get the toploader or a T56/Tremec/Richmond.

 

[cardude]

added signature with details...

This is where I am teatering on the fence... I love to be able to hammer down and give that new acura owner a red face off the line, but I want to cruise down the freeway at 75 without worrying about the engine screaming the whole time.

I am toying with the idea of 4 speed and a little higher rearend ratio, especially since I will need to do some work to the rearend in the near future. I am planning to stay with the 8" axle if I can build it a little and possibly add trak loc.

does this seem like a reasonable thing to do? or should a splurge and go for the t-5 since the weakest link will still be the rear axles?

 

[ozstang65]

If it's treated nicely, a T5 will perform admirably, hammer it and it will explode, usually 3rd gear. It's a design problem which can be fixed with $$. Apparently, as the alloy casing heats it expands a lot, losing the preload on something inside - I don't know exactly what, but it ain't good! I know this because a friend of mine rallys a Falcon in the Australian Rally Championship. Originally with only a 4 litre I6 it blew up the T5 with regular monotony until he had a straightcut gearset installed (for about the cost of a Tremec!). Cured the problem and it now lives behind a 302 in the same rally car. (Another fix i've heard of is installing an oil pump and cooler and directing the return oil line directly onto 3rd gear)

 

[D.Hearne]

If your motor's turning 3500 rpms in 3rd ( 1:1) then your rear gear is ( depending on your tire diameter) either 4.11 or 4.56. You could go with a 3.55 gearset and a Toploader and get the rpms down to around 2800 rpms at 60 ( 25 ich dia. tire)

 

[SadbutTrue]

While your engine isn't "cold," most here wouldn't describe it as extremely hot persay. This greatly depends on the cam, since you didn't list any details. But with that intake and even ported heads, you should be fine with a T5. That said, Hearne is right, a less aggressive rear gearing might do the same trick, and either stick with the 3 speed or go to four.