I know this thread old, but what cam are you running with the 4spd?
I have run three cams.
1) the 292/292/108 Mopar = 249/
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2) the 270/276/110 Hughes= 223/
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3) the 276/286/110 Hughes =230/
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The cylinder pressures for all three were maintained at close to 180 or more psi, by varying the gaskets, the deck-heights, and/or the rings; for use with the aluminum Edelbrock heads.
I ran the 223* cam briefly at nearly 200 psi, and this engine had enough balls to run the super-wide ratio A833od box, and spun brand new 275/50-15 BFG T/As, to past the speed limit, and broke them loose at 50/55 with no tricks.
>That iteration is still my all-time favorite combo. It had so much bottom end that I eventually gave some up by retarding the cam , to move the power-band a lil higher, and shifted it at up to 7200, with good results.
>I tried all kinds of things with this cam, including;
- every period four-speed that Mopar makes, and
- every rear gear from 2.76>3.91s, except 3.73s, and
- added GearVendor's overdrive, then tried almost everything from 4.10s>5.38s.
>What I discovered was that no matter what combination of gears that I tried, it always came back to;
1) having the gear in the right place from 30>60mph
2) a starter of no more than about 11/1
3) more than five gears was not required
4) this 223* cam, if I could meet it's needs for ignition timing, could make phenomenal fuel economy, the slower it idled down the hiway. In one test, it was geared the equivalent of having a 1.97 final-drive, 65=1590rpm.
In the end, I went back to the Commando box, Plus the GVod, often used as a Splitter; and either 3.23s or 3.55s. IMO the 3.55s combo is killer. and I usually split First and/or Second.
The Roadgears with the Commando/3.55s are;
10.97-
8.56-6.82-
5.32/-4.97-
3.88-3.55-
2.77, GV in red.
That 6.82 gear will get me 65mph@5500. From there I shift straight to 4th-over.
That 5.32 gear will get me; 83@5500/ 91@6000, and (with the 230* cam),
she goes 93@6100 in the Eighth-mile; having pulled the stick just once, and twice on the electric fast-as-lightning GV shift.(no ECM); this is FOUR ratios in the Eighth, with splits of .78-.80-.78 .............. the autos got nothing on me, lol.
Getting back to the A833overdrive box.
To get that magic 5.32ish ratio will require 4.10s, and so the Roadgears are;
12.67-9.88-6.85-5.34-4.10-3.29-2.36, GV in red again. and
65=1910rpm
I really liked this combo;
with 4.10s it has a great parade gear that allows 550rpm= ~3.5mph.
Because of the deep-low, I tried starting in First over; but the GV will not hold enough pressure thru a stoplight. But it will, usually, at a stop sign.
But I kept forgetting not to slam it into fourth, which instantly rips all the teeth off that tiny od gear. and when those teeth find their way into other gears, the end result is ugly.
So after the third trans, I abandoned it. Altho, after the last blow up, I cleaned the box out and ran it without the tiny od gear in it, losing the 2.36 ratio. Well. I left the gear in there but turned all the teeth off it. Then I switched to 3.55s, duh, and the Roadgears were;
10.97-8.56-5.93-4.62-3.55-2.77; again GV in red.... 6 gears, but lost the crawler gear. So I retuned, to idle in gear at 500, and got 3.66mph. Not bad. Except for one thing; the main box splits are pretty wide and splitting ALL-THE-TIME ........... gets old. I would have liked to try 3.73s for a better Second gear (6.22), but by this time, I was done with that box. Since that last switch in 2004, the Commando/GV/3.55s have stayed, except for a short stretch with 3.23s , and an even shorter stretch with 2.76s.
Also, the 230*cam went in in 2004, after the 223* cam dropped lobes. Cylinder pressure changed to a tic under 180psi.
Since that time, I have sold off everything bigger than the 3.55s except for one set of 4.88s.
Oh, BTW
Many guys complain about the modest .78 GVod ratio.
Well, typically, I shift at 2800 cuz that's when my 367 starts to growl real nice at Part Throttle; and I shift into overdrive after Third gear, and then a final shift into Fourth still in od. Here's how that looks on paper, with the Commando/3.55s
10.97(1st)-6.83(2nd)-4.97(3rd)-3.88(3od)-2.77(4od); GV in red again. The splits are .62-.73-.78-.71; as you can see, this is exactly like running 3.88s and a .71 overdrive.
From 2800, the rpm drops at each shift, are to;
1736-2044-2184-1988 (try pulling that with a lo-pressure iron-headed any-stock-stroke SBM)
enough said.