440 cam help

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phishfud

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I've been searching and reading on more sites than I can count and haven't fount the answer I need. I have a 68 440..stock bore and stroke, 906 heads. If I did all my measurements right, 8.8:1 comp with flat tops. Motor is going in a 70 Duster as just a fun street car. I'll change converter and gears as needed. I used the Comp software and came up with an XE274, but I know alot of folks don't care for the Comp stuff. So I'm looking for something comparable that's going to be fun, noticeable idle, etc. I have not built a big block before, so I'm on a learning curve of sorts. I appreciate any input you guys have. Thanks!
 
Can take a run over to Jegs web site and look up the Mopar Performance purple camshafts for the big blocks as a place to start. They have them linned up as to what the rpm range is for making the power. Match them up to how you plan to use it/drive it.

The 383s had what they called the Roadrunner Cams for the big blocks, kind of like the equivalent to the 340 cam for the small blocks, but with a little more lift and duration.

Good place to get started for your comparisons. Can't go wrong using the Mopar specs as your baseline for your cam search.
 
Looks like that 484 lift P4120235AE does not start making power until 2200 rpm and up to 6000 rpm. This cam is like #4 on their Hydraulic chart. Most people put too much cam in their cars for the street, then there is no power there on the low end when taking off from the stop lights, no vacuum for power brakes either, poor idle. Got to use a high stall converters to get them going.

The first hydraulic cam is more like the Roadrunner Cam with good performance and driveability.
P4529270AE Idle to 5800 rpm
The second hydraulic cam is a step up.
P4286677AE 1300 to 5700 rpm
 
I think your compression is too low for a decent hydraulic; I'd steer you towards a fast-ramp solid flat tappet cam

Static compression ratio of 8.8:1.
Ica of 56* at 500ft elevation.

Effective stroke is 3.10 inches.
Your dynamic compression ratio is 7.45:1 .
Your dynamic cranking pressure is.................................... 146.31 PSI.
V/P (Volume to Pressure Index) is ...........................160
This cam with a 56* Ica would be a pretty small cam as a HFT, something like a 256/262/110 and the .050 might be 210/216 but that's what it would take to keep your pressure up to create the fun 160VP

Now; with a solid, and the same after-lash specs; you might get a 217/222 @.050/110, which would be the next bigger cam, but still on the small side.
And nobody says you need a 110LDA cam in a street Duster with a 440.
So It might be possible to get a 262/268 net after lashing/106LDA cam , and get perhaps a 223/229/106 @.050, now yur getting some power out of her.

All of these were calculated with a 56* Ica, so the pressure and VP will remain the same for all of them.
I guessed you are at 500ft elevation. Higher elevations will reduce both the cranking pressure and the VP. 160 is a tire-shredder. With 160 you won't need much of a TC and can run 3.23s or 3.55s with ease. But at only 146psi, she won't be particularly easy on gas. On the other hand, she should run on the lowest octane gas you can find.
You can run a bigger than 210/216/110 hydraulic cam but the pressure will plummet, And soon you will have to install a bigger TC as the low-rpm power disappears. IMO this is a step backwards as nearly 99% of all the hours your 440 will ever drive, are gonna be at something like 4000 rpm or less, which is about 40mph in first gear. With 160VP, you can easily pull second gear with tires still spinning. Well with BFGs you could.lol. That 210 cam might power peak at about 4600 (45mph) in your 440, but with the right springs can continue to rev to 5600 (54mph) about where you would shift into second.
Each of those other cams will pick up the power peak about 200 or perhaps 300 rpm.
On the 1-2 shift, the rpm will drop to 59% (with a TF trans), so if you outshift first gear at 4600, the Rs will drop to 2700 in second, so that 440 better have some power down there. That's why I said 5600, to drop in at 3300, to give her a fighting chance to recover.
All very confusing I know.
Best advice is to contact the cam company of your choice, and get their opinion.
At higher elevations, this will become critical.
 
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.
 
If you go with the 484 cam make sure you get the 108LSA version and install it at 102 area... The bottom end will come back doing that. Unless something has changes, the MP cam line is HORRIBLY overpriced.

There are a bunch of similar cams out there and you can trick an engine with installed centerline quite a bit.

Lift is going to be a limiter with stock rockers.
 
so who are "they" that made up some **** called the " roadrunner" cam , because it sure wasn't the factory. All 383 hp motors used the same cam. I suppose there is "super bee" cam and a "charger r/t" cam too
 
so who are "they" that made up some **** called the " roadrunner" cam , because it sure wasn't the factory. All 383 hp motors used the same cam. I suppose there is "super bee" cam and a "charger r/t" cam too
Larry Shepard , most likely. The term "Road Runner" cam is used in the old Mopar Engine Manual.

mopar literature 003.JPG
 
I had that "Road Runner" cam in my Barracuda and its a great performer. Could use the stock converter and A/C with no issues. .450/.458" lift 268/284° duration
 
I went with a 292 bracket master 2 from lunati in my .030" over 413 thats about the same compression as your 440 and it has plenty of torque, 2,500 stall and 3.73s make it fun as hell.
 
A few things...

insert eye roll....

There is nothing wrong with comp cams. read that again. Some of the best engine builders in the world use CC.

Advertised power ranges means very little and mostly nothing. read that again. There are so many variables that affect this they might as well not even list it.

you need a cam that builds cylinder pressure. So you can either read up on that (start with a tighter LSA) or you can call and have a custom cam cut.
 
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