Optimum transmssion/differential combo

[jeffy]

Hi all-

ERA is building me an FIA car that will have a stroked 289 with 48 IDA Webers. I have been mulling over potential gearing and rear-end ratios, and thought that I'd solicit from the forum what others have found to be the best combination. Obviously this isn't a Weber tuning question, but I thought it made more sense to address it to the Weber crowd rather than generally.

I don't plan to do much driving around town, mostly parkway and country road cruising. No competition. Any insights will be very much appreciated!

Jeff

[FWB]

at this point your webers have slim to no effect on your trans\gear ratio selection. look to your cam choice and the weight of your car. your engine builder should be the one to direct this question to.

Fred

[jeffy]

Originally Posted by FWB

at this point your webers have slim to no effect on your trans\gear ratio selection. look to your cam choice and the weight of your car. your engine builder should be the one to direct this question to.

Fred

Thanks for the tip; I've already asked him and he is conferring with Doug at ERA about it. I'm going about my own research.

Perhaps someone who has an FIA with a stroked 289/302 with Webers can advise me on their cam, tranny and rear-end combination and how it performs. Any firsthand information will be very much appreciated.

[Anthony]

Originally Posted by jeffy

I have been mulling over potential gearing and rear-end ratios, and thought that I'd solicit from the forum what others have found to be the best combination.

Decide on which transmission you want, and then pick the appropriate rear end ratio.

[Joe@KMS]

Jeffy,

My customer has an FIA with a 302/331 and a Tremec/TKO 600 with the .82 overdrive. (Thats the tranny you out to get in my opinion)

He had 3.42 gears and did not like them (Big block guys with boat loads of torque seem to like them). He just switched to 3.73 gears. I think he will be much happier but because of the bad weather in the North East he has not been able to test them.

[jeffy]

Originally Posted by Joe@KMS

Jeffy,

My customer has an FIA with a 302/331 and a Tremec/TKO 600 with the .82 overdrive. (Thats the tranny you out to get in my opinion)

He had 3.42 gears and did not like them (Big block guys with boat loads of torque seem to like them). He just switched to 3.73 gears. I think he will be much happier but because of the bad weather in the North East he has not been able to test them.

Thanks, Joe. I have definitely been leaning in the TKO 600 direction. I very much appreciate your input.

[Three Peaks]

If it were me, I'd look at getting the Levy Racing Super T5 with .82 overdrive and go with the 3.54 rear gears. Much better shifting tranny, lighter, and strong enough to handle any amount of horsepower you are likely to throw at it. Midshift option also.

Bob

[jeffy]

Originally Posted by Three Peaks

If it were me, I'd look at getting the Levy Racing Super T5 with .82 overdrive and go with the 3.54 rear gears. Much better shifting tranny, lighter, and strong enough to handle any amount of horsepower you are likely to throw at it. Midshift option also.

Bob

Thanks, Bob! I'll look into it!

[MrMagoo]

I have a G-Force T5 with a .75OD behind my 410 stroker. I have a 3.73 differential. I have to say, I like the .75 OD way better than the .63 that was on there before. With a 3.54 rear, the .82 would produce a similar result, which I think you will like.

However, I am wondering, with the 289 presumably having less torque and with the power range presumably being further up the RPM range, would you be better off getting a higher ratio for your differential, assuming you are using stock gears for 1-4? I drive mine pretty much the way you plan on driving yours and while my motor's torque curve would handle the 3.54, I find I am satisfied with my current setup.

[AlexFIA]

I have a 347 stroker with webers with a Tremec TKO600 .82 5th gear and 3.54 rear. I am very happy with the combo. It is just right for cruising and more spirited driving. I would get a higher ratio gear for racing, but as it is it turns just around 2500 at 65 mph in 5th which is just right and at the bottom of the power band and just before things start to get loud, allowing for some nice casual cruising. I can also cruise in 4th at the same speed and be more towards the sweet spot on in the band. You also need to consider the ratio in 1st gear. The TKO600 comes in a close ratio with .82 final and the standard with .64 final. The TKO500 has a 3.27 1st gear versus the 2.87 for the TKO600. So take that into account when picking a rear end, especially if you plan on a lot of street driving in traffic.