I built this low stressed motor for the street to run on pump gas and to be installed in my 67 Coronet. So be easy on me fellas, this is not a race motor; I just wanted a good 500 hp motor. It is a World cast iron block, 512 with 4.375" bore and 4.250" stroke, Diamond dish pistons with Indy EZ heads (75cc) ending up with a 10.2:1 cr. Scott Brown hyd cam int: 245@.050" ex: [Email]254@.050" with .565" lift. Johnsosn anti- pump up lifters and Indy 1.5:1 roller rockers. Indy dual plane topped off with a 850 Mighty Demon carb. Firecore coil and mechanical dist. (last pull was @ 36 degrees total)

I want to thank Dave's Performance (QUICKD100) for helping me out and operating the dyno and doing a lot of adjustments/troubleshooting for me the last couple of days also to Maximus_Wedges and ANDYF.

Saturday we installed the motor on the dyno and after having Some timing, fuel and Demon carb issues we finally fired it up and broke in the cam. This morning (Sunday) we pulled the plugs, changed and inspected the oil filter and inspected the rockers. After a couple of great pulls with an 850 Holley, Dave went back and setup the Demon with baseline air bleeds and richened up the primary side.

We ended up with 600 ft lbs of torque@3200 rpm and peaked at 621 ft lbs@3666 rpm and stayed around 600 all the way to 4750 rpm and not dropping off much all the way to 5500 rpm(535 ft lbs). HP numbers were 562hp@5551 rpm. Needless to say, I was very pleased with the numbers. I will try and cut and paste the numbers tomorrow. This has got one flat torque curve and should be fun in my Coronet.

nice little tq monster,should be plenty for sat night cruising

that's a great street combo. you'll have a lot of fun with it. we've done dozens of similar combos like that for street use. i hope the rest of the drivetrain is up to the challenge of that torque.
should also be very easy maintenance.

Here are a couple of dyno sheet numbers

Great street moder!! Ol Mayor Dave is doing a good job on that dyno!!

Another

NIIICE job, buddy!

You'll have a lot of fun with all that torque.

Excellent choice of components, everything works together really well.

You probably have another 20+ up top with just a bigger carb, especially with that awesome indy Dual plane. My old (and very similar) 508 loved a pro-systems 1000hp.

does the dyno have any other info like bsfc, scfm, etc? would love to see it if it does. (most do)

Dave...I would have sent my new Victor up for Kevin to test against his M-1...That would have been cool!!

Ted; If we'd had it there we'd have certainly tested it. I wish I was financially independent, all I'd do is help friends with their motors and projects. (Along with mine too) Work keeps rearing it's ugly head though so most times my time is limited. Dave

Dave....I would have sent it up on my dime...No problem!! I just think it is cool what you are doing!!

Dave sure enjoys what he does and he does not give up when faced with a problem; he likes little challenges. Without the dyno and his expertise I would've probably ruined the motor if I'd done the break in in the car. Lesson learned; carb was supposed to be ready to go (don't assume anything, check it yourself) Again, thanks a bunch Mayor Dave!!!

621 ft-lbs at 3666 rpm
562 hp at 5551 rpm

That is a low rpm torque monster. Very street friendly.
Ofcourse I would have put more cam in it, the 512 CID would still have more torque than the tires will handle on the street.

Enjoy!

Thanks 440Jim, I am going to run it a while and maybe upgrade the cam later. I know from past engines I've built these big inch mopars will take a lot of cam and still idle well.

Excellent Post... Just what I wanted to read. I will be attemting to do almost the same engine here in the future for my 70 Coronet.

World Iron Block 4.395 Bore, Callies 4.250 Stroke Crank. Pump Gas is a must. Still undecided on the Heads and Cam. Hydraulic Roller or Small Solid since I have bushed lifter bores.


What oiling system are you running on this? Transmission upgrades? Rear end? and if you could change anything (or things) what would it be? AndyF and Scotty Brown are both huge helps with these combos.

Thanks for the post.

I am running a 3/8" pickup with a milodon 6 qt hemi pan. The world 1/2" adapter would not clear the rods as I am using Mopar size rod throws. I would've preferred to use the Chevy size throws but K-1 were out of them, then I could've run a bigger pickup. But this engine wont see much more than 5500 rpm. I have an external pickup setup in the box but with the stock motor mounts it would be a chore to route the line around the mounts and the power steering box. I also am going to change the dist to an MSD unit as there is no adjustment, short of disassembling the firecore dist. The advance is only 14 degrees and to get the 36 total I had to set it at 22 degrees initial and it wanted to kick back a litte on startup. I was going go with a vacuum advance dist but they would not clear the Indy EZ heads, so you are stuck with a mechanical or take the chance and mill off some of the head for clearance. I don't have a transmission yet but put a 3.55:1 8 3/4 rearend in the Coronet.

Excellent... Thank you.

you're gonna need a bigger tire...

Can't wait to see how it performs in the car. I also appreciate the post.

If I'm not mistaken that's the same (or very similar) spec cam that Paul (PHJ426 on Moparts) put in the 508 "face distorter" motor I sold to him that was in my Charger. He runs it with a sixpack and factory manifolds and it pulls really hard well into the 6000's.

I had a 252/258 @.050 Scott Brown Hydraulic roller in it before that, it was an easy 615-ish horse motor and that to hear it idle the cam seemed very mild in it but it still 'wall to walled' the massive torque and horsepower even up and over 6300. You can go to a bigger cam but if the heads work well in the mid lifts particularly you don't really HAVE to HAVE a "Big" cam and you'll still make awesome power. at 10:1 usually if your heads are non MW you can also hit a trade off point with a larger cam to where you actually give up more through the middle in torque than you gain in top end power....the only time this makes sense (e.t. wise) is if you have a nose heavy A body that just can't hook/use the big fat middle anyway.

I always have a target hp/tq in mind when I build a stroker and for the street I usually go to the smallest cam that will safely get me there, figuring nobody ever complains about a street motor having great low end roll-on drivability and manners in traffic, so long as it still delivers like a Sledgehammer when you nail it.

The best 500 motors for street duty I think have this kind of Jeckyl and Hyde personality, just add some right foot and all (you know what) breaks loose!!

Sounds great. I like the idea of a smaller cam on the street. You aren't pulling the valve covers every Thursday night for the weekend....

Quick,

I hear you on the peak CFM...but I've found on many many strokers that so long as a 500 incher will take WOT without bogging the reduced pressure drop though the middle will add some torque and also (kind of by default) give the top end charge a better run on the HP/acceleration curve.

Also that big indy dual plane has at least aonther 15-20 more HP (even at standard port size) by just doing some radius work on the plenum-to-runner transitions...particularly in the lower half.

hey what brand tires do you prefer? i want to make a safe investment on the stockmarket and that torque will make you buy new tires all the time

I have to start a savings account before long; just for tires!!!

I think we could've made over 600hp easily by massaging it and changing a few things; but I was happy and time was running out for both of us..

Any chance the motor will go back on the pump? I will take WAG That 92 octane and a great carb will pick up the pace! 600 Hp?

That's what we were thinking; it'll be running on 91 or 92 and I will be shopping for a different carb once the motor is up and running in the Coronet...

Greg; I know it would have made more on lower octane fuel, we had planed to start with 91 but ended up with a batch of water contaminated fuel. Larry and his motor are welcome ANY TIME he wants to play. Dave