I am building a pair of 502 motors. I will be using aftermarket exhaust regardless of which cam. My question is which cam is going to give me the most power for the money. I am using the GM rotating assembly, planning to use some 088 heads, having them ported, and port matched to a edelbrock 2907 and fed by holley 850's. I am not rushing to build these, I work for a living so I have been buying parts as money allows.

Pm rm builder, he will get you the most available power or tell you you're wasting time and money.

There are more factors than what you posted. Calling Bob Madera first would be a good option.
Using just those 2 cams to compare, the 741 will probably make a little more HP on the top end, but with more rpms also.
The 731 will make more torque in the mid range.
A 525EFI cam which is a 741 ground a 114 lob sep would be the best of both worlds.

I went through two different cams with my last engine (Performance flat tappet and then a 525efi). Finally decided to change directions and called Bob Madera. Best decision I could have ever made. Anyone can throw an engine together with the above cams you mention and "make it work". Bob really understands the synergy of certain engine combos, and not only produces a very powerful package, but one that more importantly, lasts!

I have used them both in 502's and 540's. The 741 was to much for the 502, idle was too rough. The 731 was a better all around cam in the 502. l later stroked the motor to 540 inches. Then the 731 was too mild, the 540 ran better with the 741, and the idle was good with it. I have a 731 in good condition but it is for gen 4 and gen 5 motors.

I have the 741 installed in a 502 and a 516 cu in. Idle quality is great. I have never heard a statement like that before, idle was to rough for the cubic inches? That makes zero sense. Maybe the cam was not properly matched with the rest of the components of your build so it did not perform as anticipated but the statement that the cam is to much for the engine size....I don't get it.

https://www.youtube.com/watch?v=acdx...ature=youtu.be This is one of them it's warming up in the vid so idle is high but again, nothing insane.

If those were my only two options, I'd go with the 741 over the 731. My buddy had 741 cams in a pair of 509's. Merlin iron heads, CMI headers, they made right at 600hp. Idle was good. HP peaked around 5700ish if I recall. The 731 cam imo, works better in a 454ci.

Without a doubt you would do better with a custom cam from Bob. Not only will you get a better all around cam, his price is good too. You're really not saving anything by buying an off the shelf crane. Now, if you are buying used cam, or already have them, then I understand.

What compression are you going to set it up with?

those heads are going to be your limiting factor. I personally, would not invest the money into porting them, rebuilding them, and so forth. By the time you are done doing all that, you could be into a set of aftermarket heads that will simply make quite a bit more power.

PS. We all work for a living.

I have the 741's in my 509's and they idle in gear at 600 RPM.
I have Dart PRO 1's that were ported by Jim Valeakeo.
If it were my money I would go with a set of Dart or AFR CNC'd heads.
The stock heads will really limit your HP. Don't waste your $ porting the stock heads.
Buy the CNC heads and you will be real happy you did.
Steve