After planning a 470 Im now thinking a 512 lowdeck. Heres the specs..512 cu in, 512 hp,630 ftlbs. 10:1 comp. Unported stealth heads,hyd 230@50 512 lift cam with 1.6 rockers.Rpm intake,7qt pan 6bolt crank. Broke in and dynoed with 12 month warranty for 7000$. Ill be using my 770 vs holly, 1-3/4 headers,dui ignition ,1'' carb spacer thats on my 383 in my 72 cuda. It has 727,3000-3200 stall,8-3/4 ,410 sure grip.3/8 fuel line,SS springs,Frame ties,adjustable shocks,28 by 12.50 15 inch tires.Battery in trunk,Factory weight,manual brakes.3" tti exhaust with hpipe,ultraflow mufflers. I want a mean sounding,tire frying,street brawler.I can change headers,carb,later if needed. should I upgrade to ported heads or change cam maybe?I dont know what to expect.How about to converter? is it to much?

A 512 is going to want a bigger cam, bigger carb, and bigger headers. The converter will probably be OK, depending on the cam chosen. Porting the Stealths will certainly increase the horsepower significantly but if you think you might want even more power later on then Indy EZ heads might be a better choice as they can be ported much larger than the stealths.

Who builds this crate motor?

Have the stealths ported, 1&7/8 headers, maybe more CR

I cant see 512 HP out of that combo either. I agree that you will need more of the important 3: Head flow, Cam AND carburetor.

IMO, not enough cam, compression, head flow and carb. Headers probably too small also. Converter might be OK, it should flash a few hundred more RPMs with the CID. If you want it set on kill, the Converter needs to go. That cam wont have much thump in a 512.

Buddy built a 512 with a hair less compression, but a 251/257 Comp Solid. Idles very tame.....

Gonna have to go with the wagon here and say the cam is much too small for a 512. I have a 541 roller for my 505cid, 3200 stall B&M, 10.5:1 cr. I am also pushing a Dual Quad (Two 500s) on my 451 now which will swap over directly to my 505

I dunno if its a coincidence but you have alot of 512 numbers in that posting....same number on cid, hp, and cam selection.

I don't know of anyone who would build a motor like that and give you more than a 30 day warranty on it. If its meant to be a street brawler, you are going to abuse the engine...and thats where the warranty would foil.

IMO, the parts combo is adequate for a strong 440, and you probably could get 1 HP/c.u. As far as a "bruising" 512 low deck goes, I'm skeptical.

ETA: After crunching a few numbers, and thinking of my own low deck combo, I believe it's possible to come in at 512HP. The parts combo would be far from optimal for a 512, but the HP results would likely be very close.

Everything you've picked is too small for those cubes. The oil pan will be fine though.

And unfortunately if you go with anything other than a stock-shaped head you're going to have to toss your DUI - won't fit.

Thanx for the input so far. This is a cme motor. they advertise in mopar muscle.They have pages of motors if you go to there website. I called and found out what is in there 512/512. I have a dui ignition for a rb but Im running an adapter which seems to raise the dist up some so other heads may fit or may not.They seem to offer options on the build.I just need sound advise before I spend on something I wont be happy with.I'm stuck on a hydraulic cam and would like a mean idle.The exhaust I have Makes great sound though. The 383 is nice but low comp .If im spending money I want the right base engine for now.

My understanding is he already has it on a motor in his car. The height won't be any different since he's using an RB DUI with an adapter. The issue is with the width ... its damn near as big as a coffee can!

I've got another 512 coming in today to dyno. This one is a pump gas street motor with indy heads and a world block. Keep an eye peeled and we'll be posting the dyno results. Dave

I am looking forward to Daves results..Sharing info is what it is about...

My 8.97:1 493 did 500hp/600ft/lbs with a purple .509, OOTB Eddies with the valve job fixed and 1.7 rockers. Runs fine on 87 regular.

You're down a few cfm in head flow and 18 deg of @ .050 duration on the cam but you have an extra point of compression. I would have the heads at least cleaned up ie fix the valve job and minor bowl work to bring them equal to OOTB Eddies and a step up in the camshaft and carb (850 cfm min) dept and you are an easy 1hp+/cu in. It will be all done by about 5000/5500 give or take and with 600+ ft/lbs on tap I would run 3.23's with a good converter as this is supposed to be a street brawler.

Kevin

I have to agree that most of your choices are not enough. I am building a pump gas 493 for my 63 and I want to run on 92 pump in the kill factor ! I went with the Indy EZ heads as I want more then the Eddy RPM's can give me. I bought them from Dwayne Porter and had him go over them and I had him spec me a cam. If you can I would talk with Dwayne Porter and see what he says as he is very smart and a very nice person. Also I went to 2" headers and I will be using the Indy dual plane intake.
But if you want a mean sounding ground shaking beast you need to make some changes for sure and the cam you chose will sound very mild in a 512. Sure you can run that combo but it wont be what you want. Ron

Not to steal the thread or anything........... But what duration cam would start sounding rough on a 505 RB ? I love that rough crackly idle.
I'm building a 505 , cnc'ed stealth heads , 11.2-1 .
My cam is a Comp Solid #23-362 "264 & 270 @ .50 with .567 & 579 lift with 1.5 rockers. Not sure If I want a bigger cam for a hot street machine or not.. 3.73 Dana with 727 Tranny , Dynamics Converter..

CamQuest is showing 643 hp & 624 torque, I know that's its only a wild guess here.


68 Cuda fastback.
Donnie