I'm a novice at this, I've only rebuilt one motor before and I just followed the factory recipe so I could use some help here. 1972 Polara 4 door sedan 440 auto, stock trans/converter,8 3/4 3:23 open. I'm looking for a strong street combo. that runs on pump gas. I'm thinking of using the Edelbrock power pkg. with a bigger cam. I wanted to keep compression around 9.0/9.5 t 1. I've been told u can run more squeeze with aluminum heads. Edelbrock thunder series 800 cfm carb, stock lower end, stock HP manifolds with 2 1/2" exhaust. Just the number of camshafts out there is mind blowing. So on the right track? Or am I performing my own rectal exam? Lets here from ya, and THANKS in advance.
440 rebuild questions options doubts
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bajajoaquin
Senior Member
I've looked at this same question a lot. My car is significantly heavier, and I've got 2.94 gears so the advice might be a little different for you. However, after talking to a few different cam companies, nobody recommended a cam with more than 220 degrees of duration at .050 lift. If you want to spend the money, there seems to be some significant advantage to going with a roller, but you still will have relatively short duration.
http://www.hotrod.com/how-to/engine/1407-camshaft-comparison-testing/
http://www.hotrod.com/how-to/engine/1407-camshaft-comparison-testing/
C Body Bob
Old Man with a Hat
I have had good luck with the RV/towing cams in big heavy B body cars. I know a few guys who have C bodies & trucks that did the Summit cams & where happy. On that Eddy carb you"re probably gonna need a heat shield/spacer under it. They tend to heat soak & vapor lock in warm weather. The fuel is the biggest problem I believe.
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I looked in the fsm and went with the with the cam that was as close to the specs on the 375 horse version of the 440 in '67 and built a nice set of 915s with bigger exhaust valves installed. It moves my Imp nicely.
commando1
Old Man with a Hat
Excellent advice.
I went with the 440/375 specs only using a Performer intake setup. It hauled *** because of the torque launching all that weight.
There may be an alternative to the bigger cam, just depends on what you have scheduled for your restoration.
I have been purchasing a low gear set from A&A transmissions and installing it when the transmission is rebuilt. The interesting thing is that in first gear torque multiplication is increased is a ratio similar to this:
Actual Rear gear 3.23 = 3.91 feels like
Rear gear 2.93 = 3.55
rear gear 2.76 = 3.23
This only effects 1st gear all other gears are the same. Really gives you much better torque for over coming inertia and you can fun a fairly stock engine for gas mirage.
Currently have this setup in my sons '85 Ramcharger , 4085 lbs. and works great. Much better than running a stall converter because it does not generate the heat a stall converter does from slippage.
I have been purchasing a low gear set from A&A transmissions and installing it when the transmission is rebuilt. The interesting thing is that in first gear torque multiplication is increased is a ratio similar to this:
Actual Rear gear 3.23 = 3.91 feels like
Rear gear 2.93 = 3.55
rear gear 2.76 = 3.23
This only effects 1st gear all other gears are the same. Really gives you much better torque for over coming inertia and you can fun a fairly stock engine for gas mirage.
Currently have this setup in my sons '85 Ramcharger , 4085 lbs. and works great. Much better than running a stall converter because it does not generate the heat a stall converter does from slippage.
twostick
Senior Member
Aluminum heads are are the way to go. By the time you properly rebuild a set of iron heads you have spent most if not all of the price of aluminum heads.
440Source Stealth if you want it to "look" stock or Edelbrock RPM's if appearance isn't an issue and you want to buy American.
Performance between the 2 is similar. No matter what anyone tells you, they will need to be disassembled and checked over before you use them and they will at the very least need the valve job fixed. For a few dollars more you can have the bowls cleaned up and you should get the most out of the mild cam you want.
AndyF http://arengineering.com/tech/ has done a lot of R+D on Mopars and he found the MP528 cam worked very well with iron manifolds. If I didn't want to put up with solid lifters, I would have someone grind me a hydraulic to the 528 specs. Link to AndyF's 528 article. http://www.moparts.org/Tech/Archive/bb/550hp.html
In any case I wouldn't bother with a roller for your application. Too much money for the benefit (if any).
Kevin
440Source Stealth if you want it to "look" stock or Edelbrock RPM's if appearance isn't an issue and you want to buy American.
Performance between the 2 is similar. No matter what anyone tells you, they will need to be disassembled and checked over before you use them and they will at the very least need the valve job fixed. For a few dollars more you can have the bowls cleaned up and you should get the most out of the mild cam you want.
AndyF http://arengineering.com/tech/ has done a lot of R+D on Mopars and he found the MP528 cam worked very well with iron manifolds. If I didn't want to put up with solid lifters, I would have someone grind me a hydraulic to the 528 specs. Link to AndyF's 528 article. http://www.moparts.org/Tech/Archive/bb/550hp.html
In any case I wouldn't bother with a roller for your application. Too much money for the benefit (if any).
Kevin
bajajoaquin
Senior Member
My basic, over-simplified understanding of cams is this: Assuming the rest of the engine isn't getting in the way, torque is determined by valve lift and the rpm of the torque peak is determined by duration. Since horsepower is nothing more than torque x rpm, if you want more power, you either get more torque at a lower rpm, or same torque at a higher rpm (or more torque at a higher rpm!).
One of the limits on valve lift is how fast you can open the valves. One of the reasons large lifts come with long durations is that it takes time to open and close the valves. The more time you have, the more lift you can get out of them. The advantage of a roller cam is that you can open valves much more quickly, so you can get pretty high lifts with pretty short duration. This can provide lots of torque at lower RPM. (I'm deliberately leaving out discussion of Mopar's larger tappet diameter, and advantages/disadvantages versus other manufacturers).
The downside of the roller is cost. Retrofits seem to run in the $750 range, maybe a bit more. That's $500 more than buying a flat-tappet cam. That's about the difference in price between rebuilding stock heads and buying 440-Source aluminum heads. Or better exhaust. Or maybe a lower first gear, as suggested above. And if you don't have the heads and exhaust, you may not get a whole lot of the gains you would get from the roller.
But even without a roller, the relationship between lift and duration is still there. So I'd find the largest lift you can get with a duration at .050 under 220 degrees. I think you'll find that's not far off the grind Detmatt got that was similar to the Magnum cam.
One of the limits on valve lift is how fast you can open the valves. One of the reasons large lifts come with long durations is that it takes time to open and close the valves. The more time you have, the more lift you can get out of them. The advantage of a roller cam is that you can open valves much more quickly, so you can get pretty high lifts with pretty short duration. This can provide lots of torque at lower RPM. (I'm deliberately leaving out discussion of Mopar's larger tappet diameter, and advantages/disadvantages versus other manufacturers).
The downside of the roller is cost. Retrofits seem to run in the $750 range, maybe a bit more. That's $500 more than buying a flat-tappet cam. That's about the difference in price between rebuilding stock heads and buying 440-Source aluminum heads. Or better exhaust. Or maybe a lower first gear, as suggested above. And if you don't have the heads and exhaust, you may not get a whole lot of the gains you would get from the roller.
But even without a roller, the relationship between lift and duration is still there. So I'd find the largest lift you can get with a duration at .050 under 220 degrees. I think you'll find that's not far off the grind Detmatt got that was similar to the Magnum cam.
One thing I'm not seeing here is any talk about high lift having an adverse effect on Vacuum. If you get up and go you still have tah whoa yeah know.
Good point, one that's brought up in the first link posted by twostick, an often over looked part of the camshaft equation.
twostick
Senior Member
There is a fairly simple solution for the vacuum problem re power brakes. Electric vacuum pump hooked directly to the booster. There are a few junkyard sources or you can spend some money and buy a new one from some of the big brake companies.
Kevin
Kevin
Landyacht
Active Member
The performer rpm package works great on big block mopars. I am currently running their heads and intake on my 470. I would highly advise going with a holley carb. although edelbrock makes great heads and intakes their carbs aren't al that great. Camshaft selection should be determined by what rear end gear you plan on running. Comp cams makes some great street cams. check out their Extreme energy series. Thier site also gives you a lot of information on what gear ratio and stall speed to run with each individual cam profile.
Landyacht
Active Member
The Edelbrock performer RPM package works great on big block mopars.I am currently running it on a 470 stroker and am pretty happy with it. as for the carburetor you're better off going with a holley. Although Edelbrock make great heads and intakes their carbs aren't all that great. Your cam selection should be based on what rear end gear you plan on running. Comp cams makes some great street cams. Check out their extreme energy series. Thier site will help out alot in selecting the right profile for your particular application.
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