Can't Decide: 4.10, 4.30 or 4.56 Gears

[67Satty]

Well, I was joking in the part about driving it 50 miles to the track with 4.86 gears. Guess that smiley I put there wasn't clear enough on that. Sometimes my humor doesn't translate well online I guess.

But...wouldn't going from a 3.91 to a 4.86 in a heavy car knock some tenths off my ET in the 1/8 mile? Isn't the idea for the lowest possible ET to cross the stripe in top gear at the same RPMs (or even a little more) than where you make max HP?

Right now with 3.91s and a 27" tall slick I'm barely getting into third gear at the end of the 1/8 mile, so I have to be leaving a lot on the table ET-wise, right?

1/8 mile gearing calculators aren't easy to find, I think when I did find one once, it said 5.38s were the perfect gear, not that I would ever put those in.

I can't really compare my car to yours for what gear is going to work because I'm guessing you have at least another 100-200 HP over me with 500-600 pounds less in weight. But if you've run a 3600-pound or so, 425 HP or so car in the 1/8 mile I'm all ears about what worked for gears.

 

[cashes65]

What worked for me was a call to A&A transmissions. Changed out the 2.45 first for a 2.75 or 2.77 low wow:hello2: 60' dropped .19 went from 11.88 to a best of 11.70 flat in good air ss spring 93 octane 906 9.5:1 440 65 bel I. 3.91 gear 28 inch tires going thru 1/4 at 6000. FTI 4200 stall thru mufflers on mt drag radials. The bonus was a little air under the left front tire. That is still with the 3.91s and it still cruises around 2900 3000 on the highway. I have also found gear calculators will get you close on paper but a loose converter will prove it in the real world. Mine flashes to 4200 and is definitely not lock up at 60mph

 

[mr. b]

I run 410s with 26 inch tall tires and at 60 it tacks around 3000 and my Richmond gears are not noisy at all

 

[Budnicks]

What worked for me was a call to A&A transmissions. Changed out the 2.45 first for a 2.75 or 2.77 low wow:hello2: 60' dropped .19 went from 11.88 to a best of 11.70 flat in good air ss spring 93 octane 906 9.5:1 440 65 bel I. 3.91 gear 28 inch tires going thru 1/4 at 6000. FTI 4200 stall thru mufflers on mt drag radials. The bonus was a little air under the left front tire. That is still with the 3.91s and it still cruises around 2900 3000 on the highway. I have also found gear calculators will get you close on paper but a loose converter will prove it in the real world. Mine flashes to 4200 and is definitely not lock up at 60mph

that's a great alternative, what ever gear is in the rear end, but especially with the 3.73:1 - 3.91:1 - 4.10:1 gears, it acts like a much lower rear gear, until you get to 2nd gear, much closer ratio too, keeping the engine in a certain power band longer, less RPM drop between 1-2 shits, also the "much" taller tire, with a "much" bigger footprint {as big as you can fit}, is also a really good idea, to help with 60ft times, especially if combined all 3 with a lower gear set in the trans & rear end, along with more tire...

 

[dvw]

1/8 Mile ONLY for this thing right now.

MikeyT, so you are saying a manual valve body could be good for another couple tenths off compared to my Transgo TF-2 - even if I'm shifting manually? I've been wondering about if a manual valve body has an ET advantage all other things being equal.

Don't get me wrong, I love manual VB's in everything. But .3 pick-up, not in this lifetime. Something had to be wrong before the swap. As for gear I've run everyone of them . 4.56 will be a help in 1/8 racing for sure. The RPM on the freeway will be up there. I cruise with 4.30 and 28" currently. Around 4000 rpm keeps up with traffic.
Doug