The 505

[IQ52]

Here is the 505 stroker for the '72 Challenger.

750 cfm Holley
Edelbrock Torker II intake
Edelbrock RPM heads
Custom grind Comp Cams street roller
91 Octane from the Stinker Station

RPM............TQ/HP

3000........513/293
3200........534/325
3400........585/379
3600........597/409
3800........599/433
4000........609/464
4200........608/486
4400........610/511
4600........613/537
4800........619/565
4900........622/580
5000........621/591
5200........617/611
5400........613/620
5600........595/635
5800........578/638
5900........573/643
6000........572/654
6100........566/657

Before we got some problems worked and the engine was only making 590 lb-ft and 585 HP we tried a Performer RPM intake and gained 26 TQ peak and 15 HP peak with an additional 30 LB-FT of torque @ 3300 rpm. We're out of time to try the RPM intake on the engine now as we have to get the 446 and 496 on our dyno.

 

[billypacemaker]

Nice build ..did you work the rpm heads or were they straight out of the box ?

 

[moaparman25]

I'm not an engine builder so this is literally just a question, isn't a 750 kinda small for a 500+" stroker? I have a 750 on my 340 and it runs really good. I always wonder about carb size, cuz I know smallblocks hailing ass with huge carbs and I see big blocks all the time with 850 and smaller. I'n always interested in how carb size is chosen. I've heard 2x the cubic inches is a good number?

 

[Chryco Psycho]

I cannot figure it out either , the factory installs an 800 CFM ThermoQuad on a 340 , the 950 cfm 6 pack on a 340 & 440 but people choose a 750 for a 440 & larger , my rule of thumb has always been 2x the CI so the smallest carb I would choose for 505 would be 950 cfm , I ran a series of carbs on my 440 , started with an 850 & it ran well , I was told it was too big so installed a 950 & the Duster ran faster , again told it was too large so I switched manifolds & went to the 1050 dominator & the 1/4 mile times dropped & MPH picked up yet again . running a 750 on a 505" is like running a 2 bbl !!

 

[moparleo]

A carburetor can only flow as many cfm's as can get through the intake, heads, and exhaust. It is the opening of the funnel that your intake and exhaust system create. It depends on the total package.

 

[IQ52]

The customer supplied the 750 cfm carburetor and asked if it would work for his '72 Challenger on the street. After the following dyno run with the RPM intake and the 750 cfm carb we installed the 505 in the Challenger and he took it for a test drive. His conclusion was..........the 750 was working just fine. There is no law that says you must run a bigger carburetor when a smaller one suits your purpose.

RPM................TQ/HP

3200.............600/366
3300.............596/374
3400.............616/399
3500.............622/414
3600.............630/432
3700.............630/444
3800.............627/454
3900.............631/468
4000.............621/473
4100.............622/486
4200.............612/490
4300.............604/495
4400.............599/502
4500.............599/513
4600.............603/528
4700.............602/539
4800.............609/556
4900.............612/571
5000.............608/579
5100.............611/593
5200.............611/605
5300.............607/613
5400.............603/620
5500.............599/627
5600.............591/630
5700.............581/630
5800.............567/626
5900.............559/628
6000.............546/624
6100.............534/621

Seems like 600 lb-ft works okay for him to 5400 rpm until 627 hp takes over @ 5500 rpm.

 

[IQ52]

Here is the same RPM intake manifold on a 496 with the same heads, slightly different camshaft. This with a 1000 cfm ProSystems 4150.

RPM..............TQ/HP

3200...........570/347
3300...........612/384
3400...........614/396
3500...........631/420
3600...........639/438
3700...........639/450
3800...........638/462
3900...........635/472
4000...........639/486
4100...........639/499
4200...........628/502
4300...........616/504
4400...........611/512
4500...........608/521
4600...........607/531
4700...........608/544
4800...........607/554
4900...........612/571
5000...........609/579
5100...........617/599
5200...........614/608
5300...........606/612
5400...........597/614
5500...........596/624
5600...........590/629
5700...........585/635
5800...........578/638
5900...........570/640
6000...........550/628
6100...........533/619
6200...........535/631
6300...........518/621

 

[moaparman25]

Sounds good man , thanks for the info!

 

[Chryco Psycho]

.

 

[IQ52]

"

 

[Chryco Psycho]

not trying to one up anyone , , if the customer is happy with 750 cfm fine , I just feel there would be more with better heads & which he has & the larger carb from my experience . As I said good #s it should pull hard anywhere!

 

[moaparman25]

Wow , that got awfully ugly all of a sudden, I've read about 1.000 posts from CP over 5 years and 3 forums, and I've never seen Anyone respond like that, maybe we should stop the "I'm better than you, so there" crap. CP is a straight up guy, super helpful, and always polite to everyone