Muscle Motors Short Block?

[Road_Runner]

Thinking seriously about buying a stroker short block from Muscle Motors to go with the top end parts I already have.  They have a 505" std block, 7.1 rod length, etc. for $4200 that looks like a good fit or for around $1100 more you can get a 540 or 572 in a World iron block.  What I already have is original Direct Connection six pack setup with manual secondary carbs, CNC'd Stealth heads, Mopar aluminum water pump & housing and will be getting TTI 1 7/8 headers & 3" exhaust.  Will my assembled parts work well enough with the bigger inch motors or stay around 500"?  The prices seem reasonable given that the stroker kits by themselves are $2K or higher.  The World blocks go for nearly $3k.  They don't mention cams but I vastly prefer a hydraulic or hyd/roller setup.  Thoughts and opinions are welcome.

Thanks, Jim

[cudabob496]

if 500 cu in motor, would definitely need at least 2 inch headers into a 3.5 inch collector,
and 3 inch exhaust.

also, seems a roller cam is always the way to go.

500 inch motors seem really affordable to build. But I think 540 or 572 can get real spendy!

[Haddixj]

If your going to do it I would definitely go with a world block no reason to run an older one just to let it disappoint you 

[Road_Runner]

if 500 cu in motor, would definitely need at least 2 inch headers into a 3.5 inch collector,
and 3 inch exhaust.

also, seems a roller cam is always the way to go.

500 inch motors seem really affordable to build. But I think 540 or 572 can get real spendy!

I'd like to go with a roller not only for performance potential but also so I don't have to run high zinc oil.  I would have thought the larger engines would be way more, but if I can use my current top end the only thing left to buy is the cam & rocker setup which should be similar for both size of motors.

Later, Jim

[Road_Runner]

If your going to do it I would definitely go with a world block no reason to run an older one just to let it disappoint you 

If the price is as close as it looks I don't disagree.  I want to build this once and run it for a long time before I have to do much to it.  So no solid cams, etc.  Reading up on the World block it does everything better than the old blocks, extra cooling, better oiling, etc. All good stuff for dependability and longevity.

Later, Jim

[Chryco Psycho]

The engine is simply an air pump , air in / air out , you will need a lot of air moving though & it will move very fast at lower RPM & simply stall out sooner .
Personally I would lean towards the world block they will take 2200 HP reliably , will it work with what you have , Absolutly , it will still make most of the power down low RPM wise as the smaller heads & exhaust & CFM of the 6 pack will limit upper RPM power But it will make a wall of torque up to about 6000 rpm , very reliable & a killer street build . 540 CI doesn't need 3" exhaust but it will limit the high rpm , I would suggest 1050 + cfm but the 900 or so that the 6 pack can flow will be ok again limiting high RPM power , same with the port flow of the heads .

[cudabob496]

I sure would think a 540 motor at 6000 rpm would need a 3 inch exhaust?

[72cudamaan]

I sure would think a 540 motor at 6000 rpm would need a 3 inch exhaust?

Only if you're trying to tweak every single hp out of the motor. 3"  on a nat. aspirated gasoline motor is
a fairly new revolution with very little data to support it's use. Especially on a street driven motor.

[cudabob496]

Looks like from this chart, my 600+hp 496 needs a 3 inch system.
A 2.5 inch system will only support about 460 hp.

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

[72cudamaan]

Looks like from this chart, my 600+hp 496 needs a 3 inch system.
A 2.5 inch system will only support about 460 hp.

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

And of course you have the chassis dyno spec sheet that shows 600+ hp to your rear wheels?

[Road_Runner]

But it will make a wall of torque up to about 6000 rpm , very reliable & a killer street build .

Wall Of Torque, OK that sounds cool.  Kind of like a Wall Of Sound from a dozen Marshall speaker cabs.  Probably sound about as good, too.  Plus, "very reliable killer street build" is exactly what I'm looking for.

Thanks, Jim