Differential and converter ratio selection for 440 magnum.

[thcmaly]

Hello all mopar enthusiasts. I'm looking for help selecting differential and converter gear ratios for a 1969 440 magnum engine. I have a 1972 dodge charger topper x with a 383 magnum engine (old converter of unknown origin) and a 2.71 differential gear ratio. Currently rebuilt 1969 440 engine, standard bore (honed), original 1969 flat pistons, new rings, lightly ported 906 heads, Torker I intake manifold, Edelbrock AVS 800cfm carburetor, Comp Cams Magnum 21-242-4 camshaft, 292/292 duration, @ 50 inches 244/244, .501/.501 cam 110. Compression 11.8 - 12 bar. The car is going to be used for street driving and a wild ride from time to time. 727 gearbox. I'm wondering what converter to use? (I'm eyeing the ACC 24093 Boss Hog "Street Bandit" fastener 2600-2800). Also, what rear axle ratio should I go for? I'd love to try a few converters but I live in Poland and shipping is killing me financially, plus the 2 month wait for shipping.

 

[thcmaly]

2.5 inch exhaust system

 

[dvw]

First of all your going to need better than pump gas. at least 110 octane. Boss Hog converters have an extreemly poor history of quality. Fairly big street cam and a single plane intake. I'd run a 3.91 gear minimum. 3000 stall minimum. Try PTC they build a good resonably priced converter. Performance Torque Converters
Doug

 

[thcmaly]

First of all your going to need better than pump gas. at least 110 octane. Boss Hog converters have an extreemly poor history of quality. Fairly big street cam and a single plane intake. I'd run a 3.91 gear minimum. 3000 stall minimum. Try PTC they build a good resonably priced converter. Performance Torque Converters
Doug

Thanks for the info, the shaft is indeed sharp (that's what I had because it was supposed to be used for another project), if it doesn't work out, I'll consider replacing it.

 

[thcmaly]

Witam wszystkich miłośników moparów. Szukam pomocy w doborze przełożeń mechanizmu różnicowego i konwertera do silnika 440 magnum z 1969 roku. Mam dodge charger topper x z 1972 roku z silnikiem 383 magnum (stary konwerter nieznanego pochodzenia) i przełożeniem mechanizmu różnicowego 2,71. Obecnie przebudowany silnik 440 z 1969 roku, standardowy otwór (honowany), oryginalne płaskie tłoki z 1969 roku, nowe pierścienie, lekko portowane głowice 906, kolektor dolotowy Torker I, gaźnik Edelbrock AVS 800cfm, wałek rozrządu Comp Cams Magnum 21-242-4, czas trwania 292/292, @ 50 cali 244/244, .501/.501 cam 110. Kompresja 11,8 - 12 barów. Samochód będzie używany do jazdy po ulicach i od czasu do czasu do dzikiej jazdy. Skrzynia biegów 727. Zastanawiam się, jakiego konwertera użyć? (Przyglądam się ACC 24093 Boss Hog „Street Bandit” łącznik 2600-2800). A także, jaki powinienem wybrać współczynnik tylnej osi? Chętnie wypróbowałbym kilka konwerterów, ale mieszkam w Polsce, a wysyłka mnie wykańcza finansowo, plus 2-miesięczne oczekiwanie na przesyłkę.

 

[68-500]

I think premium pump gas will be fine with factory pistons and factory cylinder heads. You probably have 10:1 ratio or less. Unless you had the block decked and cylinder heads milled a bunch. Did you use a factory style steel shim head gasket or aftermarket composite? As stated thats a big camshaft for a mostly stock engine I recommend looking into advancing it 2-4 degrees.
As far as gear ratio 3.55 minimum 3.91 better and 2800-3000 stall.

 

[thcmaly]

I think you're right about 10:1, and the camshaft is probably causing that compression.

 

[thcmaly]

Gaskets are standard modern ones, heads were ground, but I don't know when someone before me ground them. As for moving the camshaft by 2-4 degrees, "+" or "-", currently set to "0"

 

[thcmaly]

I think premium pump gas will be fine with factory pistons and factory cylinder heads. You probably have 10:1 ratio or less. Unless you had the block decked and cylinder heads milled a bunch. Did you use a factory style steel shim head gasket or aftermarket composite? As stated thats a big camshaft for a mostly stock engine I recommend looking into advancing it 2-4 degrees.
As far as gear ratio 3.55 minimum 3.91 better and 2800-3000 stall.

The engine has been started several times, after adjusting the carburetor to 1000 rpm it works satisfactorily. Will moving the camshaft by 4 degrees increase the power and torque in the lower engine speed ranges? My knowledge of the effect of camshaft adjustment on engine operation is still too modest, hence my question whether to leave this camshaft and adjust it by 4 degrees, or go further and buy a less sharp camshaft?

 

[68-500]

Yes it will shift the power band down a few rpms. With that cam I would definitely look into checking piston to valve clearance moving the camshaft can create a clearance problem. There is plenty of tutorials of the process.

 

[thcmaly]

Thanks for the info, too bad there are no engine dynamometers in my area. It could be a lot of fun to test the engine before putting it in the car. Can any of you tell me from your own experience what I can expect from my 440 with the setup I have (assuming I have a 2800 converter and 3.55 gearing)? I know it's a bit of a guess, but has anyone tested this setup? I'm mostly interested in how the torque and horsepower will be distributed in my 440? Sorry for my poor English, I'm using Google Translate.

 

[RJ Squirrel]

You did not mention what diameter rear tires you will be using- which will make a difference too.

 

[thcmaly]

You did not mention what diameter rear tires you will be using- which will make a difference too.

The wheel is 26 inches in diameter

 

[furious70]

26" tire I'd use a 3.55

 

[thcmaly]

Some information and answers disconnected in this post
440 cam help
I quote: "I don't have any math , but I do have a real world example and a story. In 1986 I was 20 years old. I had a 71 RR with a worn out 383. Went to the junkyard and bought a 440. Opened up the PAW catalog and ordered the cheapest forged pistons they had (TRW 2266). At blueprint spec these are only about 8.6. I read an article on pocket porting and decided to do that to my 906s. May have done more harm than good . Who knows? Had block bored, rods resized and valve job done . Ordered a big ole Comp 292 Magnum. 244 at .050, .501 lift, 110 LSA. Advertised as making you sound like the "king of the drive-in". Matching lifters and springs. Stock rockers, pushrods and valves. Used the factory iron intake and Holley vs 750 . Cheap headers. Operating on a very low budget. I think I had 1300 in the entire motor. Had a stock torque converter and 3.23 gears. Went low 14s at 102 spinning the crap out of some worn out N50s. I borrowed some old hard "cheater" slicks from a friend and squeaked into the 13s, still with a little wheelspin. Factory converter gave up and I got a cheap Neal Chance 10.75 ,pretty much like a factory high stall. Would only flash to about 2500. With some new 28x9 M/T slicks I went 13.50s. Was it soft on the low end? You wouldn't know it with street tires. With the slicks you could tell, but it's not like it was an absolute turd off the line. It was just that it really came alive over 3500 rpm. They didn't give 60 ft times at our track back in the 80s. In the 90s, the engine got new rings, bearings, timing chain and lifters and went into a 68 Satellite. 3.23 gears again. I put a 6 pack hood on it . Swapped out the stock iron intake for an old Torker. Went 13.24 at 103 on 235-60/14s and 2.5 exhaust. I put in a 10 inch GER converter (flashed to 3500ish) and with the slicks and open headers went 12.80s. Weld Draglites on front and ditched the 50 lb heater box , tuned a bit and went 12.60s. Traded the 750vs for a 750dp and one inch open spacer and went a best of 12.35 at 107 with a 1.69 60ft. The engine hasn't been apart for over 20 years. Sometimes it gets driven almost every day and sometimes it sits for months. All kinds of weather. A lot of short trips( I live close to work). Infrequent oil changes. It's tired and has a lot of blowby. Only broken part (so far) has been a hole punched in a rocker arm. And that old slow ramped Comp 292 hasn't gone flat yet. Oh yeah, the 292 sounds awesome in a 440. "

 

[thcmaly]

26" tire I'd use a 3.55

This is probably the maximum gear ratio I could use without exceeding 2800 engine rpm at 60 mph on the highway.

 

[thcmaly]

One more question: is it necessary to fill the engine with rubbing oil with zinc (e.g. Driven DBR), or can I fill it with regular oil that contains zinc and phosphorus (e.g. Driven BR40, Millers Classic Pistoneeze)

 

[thcmaly]

Unfortunately I don't have a degree wheel, but I calculated that the piston in TDC coincides with "0" on the muffler, I pulled the pushrods and put a simple tool (flat bar) on the hydraulic pushrods, it turns out that the intake valve pushrod is 4-5 degrees higher than the exhaust pushrod. I understand that in this situation I should retard the camshaft by 4 degrees.?

 

[68-500]

I have not heard of that method of degreeing a camshaft. At TDC power stroke I would expect all valves fully closed. At TCD exhaust stroke I would expect both valves open. As to which one is open more I could not predict that.

 

[thcmaly]

I have not heard of that method of degreeing a camshaft. At TDC power stroke I would expect all valves fully closed. At TCD exhaust stroke I would expect both valves open. As to which one is open more I could not predict that.

If I translated the video correctly, the valves should be in the same position at TDC. And the difference between them of 0.006" is 2 degrees.