No problems getting mine rolling, even with a 2.75:1 FDR. OTOH, I have a mild 460 CID and a 3.28:1 first gear (Richmond Street 5-Speed). Obviously this would be a much different situation if the cam had significantly more duration and less low-end grunt.

You have a large advantage with that 1st gear in terms of torque multiplication:

You
3.28x2.75=9.02

AC Ventura
2.78x2.88=8.00

Generally, you would want to be somewhere at least in the 9's. 8 is just not enough for good starts, without wearing out your clutch.

Wow 6 pages...

I've had 3 top loaders, 2 T5s, a TKO, and a Viper 6-speed.

The top loaders definitely felt different. They shifted butter smooth, and the shifter just feels different. The T5s and the Viper 6-speed also shifted butter smooth, but the shifter is different. Maybe the fulcrum is lower, so you feel more like the shifter is sliding rather than tilting.

Having said that, I prefer a 5-speed. I drove from Miami to Houston last year, and I've made several trips to Orlando. An extra gear would be nice.

BTW, the TKO was in a 428 Mustang, and it did not shift smoothly. It was tight and very difficult to shift quickly. That was a long time ago - well before I knew about the shifting upgrades.

Although we have it pretty much here, sounds like someone should just set up a poll. I don't know how to do it...

Can I just clear something up?

I thought the optimal 1st gear ratio was 8.2:1 which is the w/r t/l with 2.78 X 2.88. The very thing I had at the beginning. But Dan said it would bog down on take off, and others agreed.

So now it seems somewhere in the 9s is correct, which is the w/r t/l 2.78 but with the 3.31 or 3.54 rear end. Alternatively, the 2.87 TKO 600 with the 3.31 which makes 9.5 and has a choice of 5ths, .62 or .82.

If 9s are correct, I have to reluctantly agree, the TKO has the same ratios 1-4 as the w/r t/l but with the choice of a 70+ cruising. Hmmmm....

So what is the target for 1st please, 8.2 or something beginning with a 9,

You can get away with a WR TL and a 2.88 rear - it will take a little extra attention on starts but it is definitely do-able. For a performance gearing a first gear multiplication factor of 9 is pretty nice.

I'm a little more familiar with GM Muncies and a 2.52 WR Muncie with a 3.08 rear was not uncommon and has a first gear ratio of 7.76. A WR Muncie and a 3.31 was definitely a common set up and that gives a first gear multiplication factor of 8.3. An early Z-28 with a CR Muncie and standard 3.73 rear had a first gear multiplication of 8.2. The Z-28 with 3.73 was always know to be a little weak off the line but then it gives up over 100 cubic inches, 100 HP and about 600 lbs to a Cobra. My 66 427 Corvette runs a WR Muncie and 4.11 rear for a first gear multiplication of 10.4 and it's more touchy to drive in traffic than my ERA. Second gear starts in my ERA are really not a major problem and the second gear multiplication factor is 6.4.

So it's not an impossible or even extreme gearing - just a little out of the mainstream. I think the biggest issue would be that with a 2.88 rear and only 4 gears, the rpm drop between each gear shift is going to be quite a bit more than with a 3.31 or 3.54 rear. When you shift the rpms are going to fall way back down. That will be a drawback on that winding, twisty road you showed a picture of earlier. And driving around town in traffic you will just about have to stay in 2nd or 3rd to keep from lugging the engine or getting into a trailer-hitching, jerky situation due to the low speed engine lope.

Sorry to confuse you even more.

So, my WR TL with 2.78 x 3.31 = 9.20. So as I said, it works for me!;):cool:

Just giving you my opinion, but I wouldn't want a 2.88 final drive ratio. For one thing, getting out of the hole in 1st gear would not be optimal, sluggish really and could lead to premature clutch wear. Secondly, a 2.88 rear with an OD (5th gear) will likely put your cruising RPM too low in 5th gear. So a Toploader would make more sense here, if you didn't want the 5-speed for some reason. Can a 2.78 1st gear and 2.88 final drive ratio work? Sure. But I know I wouldn't be happy.

Lastly, as I mentioned earlier, unless your short on money and/or you desire period authenticity or "THE FEEL", then the 5-speed is your only choice. BUT, the cost difference between Tremec and Toploader is a rounding error on a $50,000-150,000 Cobra and I find the "THE FEEL" and "period correctness" points/arguments some sort of psychosis that can be cured with drugs prescribed by a doctor. :p

Just one more way to make our cars unique. When first building my car contemplated the final drive with a newly rebuilt TopLoader behind a BB decided on a 3:55 ratio. Around town it was great but highway got old fast. Next choice was a 5 speed Tremec with 3:70 gear which turned out to be the best of all worlds for me. Once the Tremec wore in a little it became silky smooth I could not be more pleased.

Time I weighed in with my opinion. I don't understand that with a light weight car like a Cobra replica, and especially with big block torque, how can getting out of the hole be a problem for anybody? Sluggish :eek: ? I would have thought that with a lower rear end ratio of around 3.5 to 1, avoiding wheelspin out of the hole would be the major problem....no?
My FIA replica will have a 2.92 diff ratio combined with a WR Toploader. That's like a five speed without a first gear, but I can't see any problems getting off the line with it. If it's flat or downhill and I'm in no hurry, I start in second gear in my old Alfa (150-odd thousand miles, and still the original factory fitted clutch)....no problem whatsoever because it's so torquey, so I can't see any sweat at all with my aluminium chassis'd replica with mild 302 engine. 60mph in first gear will be available, and so will good highway ability.

Just thought I'd stir the pot a little more. 6 pages??

:3DSMILE:

Cheers,
Glen

The camshaft will make a huge difference. Most folks want a lumpy camshaft. A few want a mild RV type cam. The bigger the cam, the harder it will be to get off the line. However, there's a reason why car manufacturers offered deeper gears (higher numerically) as performance options back in the day.

But report back after you've had some time behind the wheel. I have a 3.42 differential and it's perfect. Although I think Kirkham offers 3.54 as standard nowadays.

Will certainly post when it hits the road.
Surely you can go too short with the gearing though?
What's the use of wheelspin, lots of revs and noise, but not much speed?

Cheers,
Glen

One more thing...
 

Let's also remember that the TKO has a neutral safety switch as well (which I just hooked up after doing without for ten years). For me, the TKO600 with the .64 overdrive and the 3.54 rear was absolutely perfect, in every way. You might want something different though.

Let me think about that Patrick.
OK, I thought about it. I'll forego the safety switch, and stick with the Toploader.

Cheers,
Glen

Yep. Just keep it simple. 4 to go!:cool:

And why would someone want to go 60mph in 1st gear ever?

The only reasons to stick (no pun intended) with a Toploader:

1. Can't afford it.
2. Period correct/authenticity.
3. The "feel" of a Toploader.

I kinda understand #1, but #2 and #3 make no sense to me. Good luck anyway. :)

BTW, I hear 3 speeds can be had cheaper than a Toploader.

One of my favs of all time was my T-85 3 speed with overdrive in my '61 Starliner. Like "butter"..;);):cool:

Oops, double post.

?? Why wouldn't I want to go 60mph in first gear?

My Toploader and Hurst shifter, properly rebuilt by an expert to as-new condition (David Kee's agent), cost as much as one of them there fancy 5 speed TKO thingies.

No.
OK, it is a period correct gearbox, fitted to 427-engined cars, but a T-10 (of course) would be the correct fitment to a 289 engine Cobra.


Well, feel is a personal thing. The Hurst shifter is like a rifle bolt in its action. I like it, and that's what matters, Rod. I'm not trying to convince anybody :D

Thanks.

Err, umm, I wouldn't go down that path myself Rod, but I suppose if you wanted to, that's entirely up to you....I guess.:LOL:


Cheers,
Glen

Being able to exceed 60 in first does wonders for your 0 - 60 acceleration time due to not having to shift. Actually 60 mph in first might be an understatement. A WR Toploader with 3.07 rear and 26 inch tires does 9.1 mph/1000 rpms which with a 6500 rpm motor puts it right around 60 in first. A 2.78 would probably do closer to 65 to 70. Second would be good for around 90 mph +/-. Third for about 125 +/- and fourth for about 160 +/- at 6000.

I consider myself an eco recycler :3DSMILE: - that's why I have a 70s block, 61 heads, 63 intake and distributor, and I think my Toploader is from somewhere around 1970. I guess I need to check out the date codes on my Jag differential. I like vintage, nostalgic stuff. When I'm driving and shifting my Corvette or ERA it takes me back to the 60s/70s in my GTO/Corvette/Trans Am days. When I'm driving my 6 speed Mustang GT in traffic I feel like I'm driving a Mack truck by the time I get thru all 6 gears after a light. But, I think I'm repeating myself - guess that makes me "vintage" too.