you will need some form of forced induction to get that kind of power from a 318. as well as a rock solid botom end.  

A LOT of cam, LOTS of compression, LOTS of carb, radically ported heads, BIG hedders,...wait a minute, that's a race motor.  But 500hp is possible.  

318 500 horse?
Anything is possible but not necessarly practical.

Save your self a ton on money and get a 360, your automatically getting 40-50 horse in cubic inches.
Then you decide, 360/450 horse or 408/500 horse.
Heres my recipe for the 360 cu. in,

1. 9.5 compression
2. I beam rods.
3. solid cam, mopar performance 284/.528 241 duration at .50,advance 4 degrees.
4. RPM air-gap intake, with 750 d.p. with 50 cc pumps, upgrade the metering plates to quick flow units. Jets 71 front with 6.5 power valve, 82 jets rear with rear power valve plugged.
5. MSD 6al rev. limiter set to 6300.
6. headman 1 5/8 ceramic headers.
7. Proform 1.5 roller tip aluminum rockers with hardened adjusters and locks.
8. Any good LA heads Ported and Polished.
estimate 447 hp.

408 cu. in. Same as above and add the following,
10.5/1 compression.
6-8 degrees more duration at .50 for the larger engine.
hooker super comp 1 7/8 headers.
H beam rods.
800 cfm holley double pumper 50 cc pumps with quick flow metering plates.
Edelbrocks aluminum heads, Ported & Polished.
estimate 500 hp.
Obviously the 360 is more affordable so you decide if the extra 50 horse power is worth the added expense.
If you insist on using your 318, stroke it to 402 cu. in and copy the 408 build as outlined.  

drmopar, where did you find a 402 stroker kit for a 318? All I'm finding are 349 ci. with the 3.58 stroke and 390 with the 4 inch crank. If a 402 is possible, then what will the crank be? I'm thinking about building a stroker 318 since I've got two of them boat anchors. I do agree with you. Why build the heck out of a 318 to 500hp when you can make a 500hp 318 stroker a lot easier and probably cheaper.  

For some people it's bearing speed.
For others it might be the fascination of making big power out of a lil motor.
Really the 318 ain't all that small look @ others, 289-302 ferd,283-305-307-327 chby.
I tell you the 318 is no slouch!
With the right heads and the ability to rev, the 318 can dominate.
Besides if pubic inches is all that matters then we would all have stroked RB's not 360's and so on...

oh and there is a crank thats 4.125 for the small block.  

Sorry the 402 is based on the 360, however you can get a 3.79 & a 3.90 callies cranks, I know of one fellow that installed a four inch crank from a 340 in a 318 giving it something in the neighbourhood of 396 cubes, bored .040.
All these cranks would crate a killer torque monster,  Try and keep the rotating mass as light as possible, pistons, I beam rods, and you will make your 500 horse with a good solid cam in the .550/.570 lift range.  

Ohio crankshaft sells a 4.125 for 2.50 or 2.81 main size,.030 318=404ci.
Add that to a .040 340=431ci or they sell a 425 kit.
Pretty cool.
Some australians are selling  4.180 stroke cranks for the sb  also.    

I cant believe you are dinging comp cams dino they did use non corrected nos, that would have given you app 399hp corrected. Our mtr was .5 hp different raw no, to        raw number from one dyno to the next. we used a dts state of the art dyno not desk top.400 hp is a great no, to get out of a 318 cause that is a real number not some pumped up number just to sell a mtr.  

Hey buddy, Been a while how you doing?  

great been to far behind at the shop to log on !  

Good to hear your working, there are many not working right now.
So what you working on?  

schurbeng I only know what I know. I had that engine dynoed for the customer that bought it. He wanted it tuned for his carb and exhaust. It made 500+HP at 7000rpm. And carried it for 1000rpm within 10hp. Iv seen it run at the track, and No one believes its a 318. 11.6 in the 1/4, full body and interior Dart about 3300#. No way 400hp will do that. I stand behinde my engines 100%.

I have built several(10 or more) 318's that made 400hp or a little more with a lot less rpm, cam, head compression. That Dyno was not right. Daves engine from Mid America HAD to be makeing well over 500tq and 630hp. It didnt suprise you that no engine made 500tq? NON of them! I just got done with a 408 build, 10.3 compression, RPM intake and heads(port clean-up only), Voodoo 405 cam dynoed at 500hp@5700rpm and 521tq@4100rpm. Muscle Motors engine only made 450hp? Bull, it was making a lot more than that.

And Knock the Desktop Pro SIM all you want. I use it to model an engine before any parts are bought and its pretty damn close every time. Most cases within 1%.

Dont get me wrong, I loved your Purple Beast. It made great power and would be great in any street car. Id buy it  

67dodge not knocking desk top but my dyno guy is so tight on his numbers I am just saying there are not a lot of honest dynos out there mine only made 509 corrected on his dyno else where it might have made 560 who knows. i am just saying yours ran good and in comparison per cubes it was strong regardless of dyno.  

Two 500 inch 2 408 one cast head one edelbrock heads and a 572 hemi pluss a bunch of #$$#@%$ you know.  

Cool.
Have you used the mopar cast 4' crank for the 408 and what do you think?
I ask cause I have one I'm throwing together and I found only about a thou of crank end play and now have to have machined. I t also comes close at the back side of #4 main.
I got the crank from Ohiocrankshaft and if I remember right they said it was a MP nodular crank, anther guy said it looked like a scat crank, who knows?