Well, I can tell you this, My little 367 went 93(1/8) through the aluminum cased o/d box. Oh poop, By that time, I had the front end bushed already.
Ok let me start again. I think I mightof put 20,000 or more hard miles on an aluminum cased o/d box before I bushed that front hole.Eventually I purchased a Passon case.Not because the factory box was making any trouble. I just wanted a box for the 3.09 gearset that Passon was supplying me. I got one of his covers too.And I already had the GV with it's aluminum adapter. So now I am all aluminum.
My 367 is similar to the Hughes Engines unit they call Brett's Combo or something like that. They claim 437/437 with theirs. So potent but sweet.
#11---360 Dyno Test (Feb 2000)
I blew up two different o/d gearsets with that engine.but the case survived both hits. In one box I forgot to go easy on the 18tooth O/D gear, and gadzooks I stripped all the teeth clean off it. The next gearset let go on the maindrive. Again all the teeth AWOL. So people say that box can take a licking, but IDK. I'm 2for3. I abandoned it. I got me a 3.09low/direct 4th set, and it has outlasted the ods about 4 or 5 to 1, and is still going.
I can't say you will blow yours up, but if you're making over 450, I suppose chances are pretty good that you will. And I gotta tell you something else my 367 didn't like the splits much in that box; they were just way too far apart; that's why I got the GearVendor, cuz it neatly splits first and second, and I used it after second as well. This seriously tightened up the splits. with 3.91s I can hit 111@6800, at the top of second-over,and I only pulled the stick once,lol.
But without the Gv, the splits were really really wide, almost two gears worth wide.My 367 didn't like that at all.
Just to recap; the ratios are 3.09-1.67-1.00-.71od, and the splits are
.540-.599-.71into od which you have to be gentle to.
So around town I used to shift just under 3000, usually 2800, cuz the pipes sing nice there. Well if you shift 1st@2800 then it comes into 2nd at 2800x.54=1512, and my engine has nothing for torque down there.The 2-3 is a bit better. Again outshifting 2nd at 2800, it drops into direct at 1677. That kindof sucked.
My 367 doesn't really wake up until over 2000, but it's tolerable from 1800. This requires outshifts at 3300, and 3000.With 3.55s making a nice 3.09x3.55=10.97 starter gear, the speeds associated with those shifts are 24 and 41. So as you can see 3.55s are a more or less useless gear on account of the common cruising speeds in the city are 30 and 45, and I'll either be buzzing or lugging.
If you work the math backwards and ask what rear gears can I use to cruise comfortably at those speeds of 30 and 45. Well really you can't hit them both cuz 30/45=.67 and we have no .67 split. So you'd have to pick one. But again working backwards 30/.599=50 so you can hit those two; 30 and 50. One in second and the other in third.
So let's say you want to hit a comfortable 2400 in second with27s at 30mph. The math looks like this; (30x1056)/(85x2400)=.15529 which is 1/.15529=6.43 overall gearing. Dividing that by second gear; we get 6.43/1.67 =3.856 rear gear. which I would round up to 3.91s of course.These will get you a nice starter gear of 12.08 great for dragracing. The Rs at 30 will be 2434 in 2nd, and at 50 will be 2429 in direct; looks good. And 65 in od will be 2242. This all looks pretty good,right? Right up until you try to drive it with soggy bottom end or big-cam engine. The soggy one will have to downshift every time to get moving, and the big cammer banging thru the gears,will have to outshift first around 42.5mph@6400, which drops into 2nd at 3456. Got torque there?
Since we know that the power peak is usually about 1500 rpm or so further on down the road from the torque peak, a big-cam engine that wants to shift at 6400, will likely power-peak around 5800, and that means the torque-peak will be around 4300. So, at 3456..... at least the torque is moving in the right direction.
So AJ , what's your point? Well, I'll tell ya, pilgrim......
This box likes exactly one kind of engine, and it better have a very wide torque band, and probably a very early power peak, cuz it's gonna be pulling hard all the time.
My 367 didn't like it. Not with the 223* cam, and not with the 230* cam.And not with any gear in the back, with the possible exception of the 4.30s; but those made first gear pretty useless.
If I had to guess, I'd say she (my 367) mighta bin ok with a 210ish or smaller cam.That's a guess.
If you have a bigger engine,with a relatively small cam, you will have a better chance
Parting shot;
With the GV on the back and splitting gears, it was fabulous. But I HAD to split the gears, almost all the time. And that got old after the first summer or maybe it was two. The gears looked like this,GV in red;
3.09-
2.41-1.67-
1.30-1.00-
.78-.55; seven useable gears.
The splits; .
78-.69-
.78-.77-
.78-.71
With the 4.30s; 65mph was 1923rpm
With the tight splits, the engine really sings at the track sitting right on the power peak almost all the way to the traps, running on about a 1300rpm powerband, with maybe a 15hp drop from minimum to maximum power.That was the payoff;93 mph in the 1/8.And 3 gears to go.
But,I don't run that box anymore.And no, I didn't break the third one.
So just to be clear, I'm not ragging on that box cuz I think it's weak. I am ragging on it cuz it fills a very specific niche, and a guy kindof has to match his engine to it, for a reasonably good outcome.
