Making my 440 more streetable

[msbaugh]

70 challenger, the 440 I bought running as is without paperwork. Here's what I know: it's supposedly .030 over with a more aggressive hyd cam (don't know any specs) and stock stamped steel rocker set up. I've put a eddy rpm manifold, hooker super comp headers, Mopar electronic ignition and 750 holley dp on top. Originally had 3.93 geared 741 small stem pinion case, not sure exactly but the 727 has a very high stall torque convertor ~3500rpm and it flashes to ~3750rpm when I romp on it in D on the highway. Seat of the pants-o-meter puts me around 450hp best guess. The thing would destroy the bfg tires at will.

The problem with the set up is that I was spinning 3500+ rpm at 45 mph and I would run out of motor so quick. I'm talking top speed of 75 mph is all it would get up to. I decided what the hell and bought a beefed up 489 8 3/4 case with a modern true trac sure grip and 3.55 gears and hoped for the best. Now I've irritated the combo. Lol.. Ever driven a high stall convertor around that doesn't want to lock up? It's horrible. I feel like the heat is going to bust the torque flight up. I always manually shift this thing. It shifts very hard and sometimes has a delay into second if I don't give it enough throttle. I'm going to try and figure out the throttle pressure adjustment and drain the fluid/convertor and change the filter to see if it helps. I've thought of buying an external tranny cooler as well.

What would y'all do knowing as little as I do? I'm thinking about a new 2600-3200 stall convertor to help driveability. Hopefully enough to keep it in the cams power band but low enough to get this thing drivable around town. I can always put the 3.93 back in after a couple hour job but I want reasonable driving and want to stick with the beefier 489

[Chryco Psycho]

I agree , 3700 stall is no fun after a while especially if you want to drive it around 2500 on the highway so a good converter would be my first step , Cam is a question too , a cam swap could make it more driveable in the range you want to use the engine without loosing HP just moving the powerband where it works better

[HP_Cuda]

Finding out what cam you have definitely will help you choose the right converter.

Without that time to change it to the performance profile you want.

B

[msbaugh]

Anyone paid the extra $$ for a dynamic 9.5" convertor? One that stalls say at 3200 wouldn't be much less than now but enough to improve drivability. I hear even with the smaller diameter and higher stall a good quality unit won't feel like a high stall until you romp down and flash it.

I'd like to keep the higher stall but lower my cruising rpms and improve around town driving. It's an expensive gamble isn't it :-/

[Strawdawg]

To do it right, one should match the stall to the torque curve. Set the stall rpm to the point where the torque begins to flatten out

Steve

[msbaugh]

Ok. I'm bringing up another couple of questions here. My transmission is acting horrible on me and getting worse by the day. I think the higher 3.55 gears and high stall is burning it up even with the adjustments, deep sump, and cooler I have on it now. It's not wanting to shift right and now it slips under wot

1st: my trans dipstick says DEXRON ONLY, do they all say that or is it there because a specific rebuild calls for it? I put type F in because it was cheaper should I not have?

I really like the way the stall and cam worked with the previous 3.91 gears. The thing got up off the line like a bat out of hell.  Not quite so much anymore with the 3.55s.  The only problem was high rpm highway cruising, especially with 25 1/2" tall tires. After the trouble, I'm reconsidering what the car is really enjoyed for and after everything I've done I think the only solution is to put the 3.91 gears back to make the convertor happy again. What I can do is take the beefed up 3.55, 489 case and swap the 3.55 gears in it now for a new 3.91 gear. I'll put the second 3.91, 741 pig back in in the mean time and by the time I'm done I can sell the smaller stem duplicate.

I think I'll deal with the high rpms now and long term save up for a gear vendors or passon 5 speed!!!
Any thoughts??

[cudabob496]

Have tranny cooler lines bypass radiator and go to a B&M stacked plate tranny cooler, mounted in front
of radiator.

Spinning at 3500 rpm at 45 MPH?  Normally I would think you had 4.55+ rear gears with those numbers.

Sounds like your converter is toast.  I have a Hughes 3500 stall, and 3:91 rear gears, and I'm at 3200 rpm
at 60 mph.

[msbaugh]

Have tranny cooler lines bypass radiator and go to a B&M stacked plate tranny cooler, mounted in front
of radiator.

Spinning at 3500 rpm at 45 MPH?  Normally I would think you had 4.55+ rear gears with those numbers.

Sounds like your converter is toast.  I have a Hughes 3500 stall, and 3:91 rear gears, and I'm at 3200 rpm
at 60 mph.

That probably wasn't the exact MPH... it has been a while since then so I was ball parking a number. No doubt the convertor is inefficient on the highway, but I don't think it's toast yet. 25 1/2" tires and 3.91.. Do the math and I think it's pretty close.

Are you saying bypass the radiator cooler completely? I have the front pressure line coming out of the 727 going into the external cooler, then out and into the radiator, from there out of the radiator cooler to the rear line back into the 727. The external cooler is in front of the radiator but is horizontal as to avoid blocking engine cooling capability. I'll try moving it verticle

[Strawdawg]

Nothing seems to calculate.

with a 3.91 rear, you should be doing about 85 mph at 4500 and about 65 mph at 3500.

With a 3.55 rear gear, you should be doing about 94 mph at 4500 and about 72 mph at 3500 (I added a little slip when I calculated the mphs)

Your converter seems to be around 3500 as you said based upon the flash.

So, the question is, where is the mph?  You verified the speeds with a gps in your phone? 

Otherwise, it sounds like your tranny is slipping like mad and it does not sound like it is the converter based upon your comments

The engine should be roaring at the speeds you mention....no one connected the tach as six cylinder?

[cudabob496]

of course, for the rear different gears, gotta have the right
gear in your tranny that drives your speedo, to get correct speed.

On any performance tranny, I would bypass the radiator, which
may be heating your tranny fluid.  On the return cooling line from my
B&M cooler, I have a temp gauge that rarely gets above 160, even
though I have 3.91s and 3500 stall.

The cooler I have is about 1.5 inch x 8 inches x 11 inches. Its mounted
about 3 inches in front of radiator, so there is no real air blockage.

[Chryco Psycho]

F type is actually better for the trans , so that should not be an issue

[cudabob496]

F type is actually better for the trans , so that should not be an issue

F Type?

[Strawdawg]

Pull the dip stick out of the tranny.  Smell the fluid.   If it has a nasty burnt odor, the tranny would appear to be wasted. If you don't know what burnt fluid smells like,  smell the fluid from another car to see if they seem the same.

If the fluid is OK and up to the normal level when hot and in neutral, then look elsewhere.  As your rpms are nowhere close to your observed mph,  verify the speedometer with gps or another pace car.

Steve

[jhaag]

Bob. type f tranny fluid was used in Ford vehicles back in the day. It has different friction modifiers and was recommended for all performance trannys before high performance fluids were available.

[cudabob496]

Bob. type f tranny fluid was used in Ford vehicles back in the day. It has different friction modifiers and was recommended for all performance trannys before high performance fluids were available.

ok, thanks!