Howdy! Please critique this build, 340 stroker

[laramie]

Thanks for looking.  I am new here, grew up driving my dad's 72 and 74 Challengers about 10 years ago and have had a 70 cuda in the barn for the past 15 years. (yeah, I know, shame shame.)  Thankfully, the Air Force is moving me close to home and I will have time to finish the cuda in the next couple years. 

Any advice is welcome. The big things are cam choice, and stroke given the stock block.

Goals are 500 hp at 5000 ft pressure altitude and under 7000 RPM. The engine will go in a 4sp cuda and will get some track and some street time. This isn't a cruiser car. I want loud, fast, and reliable.  This isn't the quiet car. I want to use an original six pack on this car, at least initially. Eventually I will likely put a TBI kit on it.

Block - Original Chrysler 68 or 72 casting depending on which is heavier.

Top end
Induction - original Al six pack
Heads - Mopar Aluminum LA Commando, to be ported by a pro. I want to give Ryan at Shady Dell a call once I get closer to doing this. 
Rockers - 1.6 Hughes or Harland Sharp
Cam - solid COMP Cams 249-CL20-231-4
-Intake Valve Lift (in.)0.520
-Exhaust Valve Lift (in.)0.54
-Int. Duration @ .050 in. 244
-RPM Range2500-6500
-Exh. Duration @ .050 in. 252
-Int. Duration Advertised 282
-Exh. Duration Advertised 290

Bottom End.
The 372 was my original thought to keep piston speed and torque lower on the stock block. However, I am leaning more toward the 4" stroke at this point.

Option 1 http://www.jegs.com/i/Scat/942/1-48005BI/10002/-1
3.580 stroke Forged Scat kit, 372 CI, 10.2-10.5 CR
Scat I beam rods, 7/16 bolts
forged pistons

Option 2 http://www.hughesengines.com/Index/products.php?browse=category&level0=QS0gU21hbGwgQmxvY2sgIkxBIg==&level1=U3Ryb2tlciBLaXRz&searchmode=partnumber&page=2&partid=28825
Hughes 4" premium mid CR scat kit, 416 CI 11.8:1 CR
Scat H beam rods, ARP bolts
Forged Scat crank
Icon forged pistons
total seal rings
etc.

The rest of the parts include MSD ignition, windage tray, possibly a girdle, Scat dampener, and a high flow melling oil pump.

[cudabob496]

go with a dual feed carb on a single plane.
Easier to tune and more power.
6 paks can be a headache sometimes.

and I'd use a roller cam.

[Oldschool]

Since the cost is very close between the 372 and the 416 CI builds, I would go ahead and go 416 and add a little more cam for the added stroke and you will be fine. Not a huge fan of the 6-paks for serious performance. Also a solid roller cam would help at 7000 rpm you are looking to run.

[moper]

In order to make 500hp at 5K' you will need to make about 600 (20% more) at sea level. IN terms of supporting that level of power - the cam is too small. The heads might be usable if Ryan does them. But I'm certain unless you already have them, that less expensive heads can make more power with similar preparation. You need a solid 300cfm below your cam's lift range to make 600hp under the right circumstances. The MP heads don't clear 300cfm until over .600 lift. And that's after pushrod angles and lash. I would advise some modifications to your build: Do the 416. Prep the block for a solid roller cam, and use heads that give you at least 290cfm at .500". Teh Airwolf heads come to mind as a less expensive alternative to Indy 360-1s. But one way or another you're spending on decent heads & getting them set up properly. Get the lightest H beams you can get (I think it's either Molnar or BPE depending on the crank pin size) or a good set of I  beams if you want 7K. Order a custom solid street roller from Bullet. You'll want the Super Victor intake too, and at least a 950HP carb. 

[cudabob496]

hp loss = (elevation x 0.03 x hp @ sea level)/1000

[moper]

hp loss = (elevation x 0.03 x hp @ sea level)/1000

It's not a flat rate of loss, it's a curve. It's like trying to go faster: it's easy to go faster when you're starting from 14.0. It's much harder to go faster from 12.0.
Once you get past a power level of around 450hp the loss is closer to 4%, and when you're over 550hp it's closer to 5%.

[laramie]

In order to make 500hp at 5K' you will need to make about 600 (20% more) at sea level. IN terms of supporting that level of power - the cam is too small. The heads might be usable if Ryan does them. But I'm certain unless you already have them, that less expensive heads can make more power with similar preparation. You need a solid 300cfm below your cam's lift range to make 600hp under the right circumstances. The MP heads don't clear 300cfm until over .600 lift. And that's after pushrod angles and lash. I would advise some modifications to your build: Do the 416. Prep the block for a solid roller cam, and use heads that give you at least 290cfm at .500". Teh Airwolf heads come to mind as a less expensive alternative to Indy 360-1s. But one way or another you're spending on decent heads & getting them set up properly. Get the lightest H beams you can get (I think it's either Molnar or BPE depending on the crank pin size) or a good set of I  beams if you want 7K. Order a custom solid street roller from Bullet. You'll want the Super Victor intake too, and at least a 950HP carb.

Thanks. 

After some offline discussion, 4" it is.  I haven't found any decent enough deals on airwolf heads to make it worth it... I want quality.  I am a big fan of buy once, cry once. 

What solid roller lifters do you recommend?  I haven't talked to anyone with solid rollers that have lived very long off the track. 

Also, 6 pack is staying for now.  It's eventual replacement will be a custom EFI or Holley EFI system.  If I decide from the get go to do EFI I might try to find a good set of W-2 heads. 

[Denison636]

Take a look at the small block builds. I got a 416 in there that made 527 hp

[laramie]

Take a look at the small block builds. I got a 416 in there that made 527 hp

Thanks!  I am still learning my way around here.  What altitude are you at?

[Chryco Psycho]

I think the Cam is a weak link .
You can get a solid cam with close to .600 lift at the  same duration that cam offers  , Duration & overlap will control the rpm where the cam makes power , lift is free . Lunati offers some flat tappet solids with close to street roller specs & performance
 Airwolf heads are a good call , W2 or W5 an make serous power too but are expensive , if you want to get very serious you Could use an R3 block with w8 or 9 heads

[Denison636]

Elevation is at 545 ft when the dyno pull was done