Back to overdrives;
the GVod is nearly a bolt-on and requires no floor cutting, only a little stretching in two spots, to prevent rattles. If you wanted to, you could probably just jam it in there. It took me less than a minute to clearance the floor with a big hammer......... but I did have to drop the od unit several times to get the dimple in just the right spot. No biggie cuz IIRC the Unit only weighs 23 pounds.
The fun part with the GVod, is that you can use it as a gear splitter.
I would highly recommend to use it with a higher-stall loc-up A999, and 3.73s
(depending on your power-peak, see below); for ratios of ;
2.74-2.14-1.54-1.20-1.00-.78, and splits of;
.78-.72-.78-.83-.78
Most of the time you will be using it as a 3 or a 4-speed for 70=5580 in Second, then dumping it into overdrive. The
road-ratios would be; 10.72-7.97-5.74-4.48-3.73-2.91 splits of .78-.72-.51od
This starter-combo of 10.72 is the same as the regular Torque-Flite with 4.37s.
Even with a factory loc-up, you'd be hard pressed to find a better set of street-gears.
>Passing gear at 55 could be Second gear (1.54) for 55=4300(10%slip), and that gear will go to 70mph@5500 still at 10%slip.
> 32mph is 4470 on the 2-1 downshift, and goes to 39@5500, then 50 in First-over!
>BTW; did you count the gears? I get SIX ratios with reasonably spaced and tight splits.
>if you gear it right in the back (for your power level), to use that .83split from 2od to direct at the strip, then; you can stay on the cam for a lotta mph thru the traps.
>If I didn't already have a really nice Commando combo, I would have the above.
Say your car can hit 106 in the Quarter.( about 330hp)
To hit 106 in direct@5400 requires a rear gear of ~3.73
So with a power peak of a typical 5100, and a regular TF, you would hit 5400@72 mph at the top of Second gear and so Direct has to pull from 72 to 106. That is a long pull cuz 72 is ~3700 in direct.
But using the A999/GVod and still the 3.73s, Second-over would top out at 88mph, having used 4 ratios to get there, and dropping into Direct, would get you 4500@88mph for the race to the traps..... having used FIVE ratios, Hitting od after the traps will get you 106 @4200
Do you want to run 3.73s on the street? With od, sure you do, lol. So then, you are always ready to go.
A 5100 power-peak requires a modest cam of about 224*@.050. It will just pull that 2.91 Final-drive at 65= 2330 @ loc-up..... with nearly full cruise-timing of about 50*
And Finally, if you want to, you can put the GVod into AUTO-mode and forget about it.
Remember;
1) the starter gear of 10.72, is the equivalent of 4.37s with a standard 904/727
2) Final drive is 2.91, for 65=2330/75=2690, now easily able to get full-cruise-timing of about 54*
3) I would likely run it with 3.55s and a cam one size smaller, and it would probably still get into the 12s.
But I gotta tell ya;
If you have a 360, it would be a heckuva lot cheaper to run 2.94s with the same A999loc-up and a higher stall
The whole reason to run that splitter set-up is in compensation for a low-torque engine..... which a properly built 360 is not.
----------------------------
If you put alloy heads on a 360 and hi-compression pistons, you can run it up to 185psi no problem, still on 87E10, and still with full-timing. Plug a modest 220/224* cam into it, and run the same 2.74-low trans, the same 2.94s, for the same low-rpm cruise, still with a reasonable starter of 8.06, and still have gobs of tire-spinning take off, with say a 2800TC.
And all that Compression will pay dividends at every rpm and every mph.
The bottom line is this; the alloy heads and pistons will cost you less than the GVod (new). You can even almost get them installed for the price of the GV. And I guarantee that your 360 will get old and tired, before you get tired, of that smoking hot bottom-end.
OOps I see I'm a really slow typer, and a few more posts slipped in , lol.
The stock 340 is a pig on gas, I know; I have had 4 of 'em all from 69 to 71, and at least one of them was new. They suck gas because of;
1) the Late-closing intake,which steals torque, so you are always on the gas, and
2) in conjunction with the early-opening exhaust which leaves a lotta energy still in the expanding gasses when it opens.
Get rid of the factory cam.
then run, no more than 3.23s, for 65=2600 with 27" tires.
Depending on your cranking pressure, and rear gears, I might go down to a
[email protected].. With iron heads and log exhaust, I would run a 268 on the exhaust. and tightened up to at least 110. To recap then, 262/268/110, in straight up to plus 2, on a 10/1 engine that will give you about 7* more compression, and maybe 10psi CCP, and the exhaust goes about the same. That will make a huge deal in MPGs, more than an overdrive.
The new cam would need a re-tune.
I would swap in an A999Loc-up for the deal-sweetener.
