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512 Stroker Six-Pack Build

jphemi70

jphemi70

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My son and I are restoring a 1970 RR. We got a 440 to use the block to make a 440+6 for the street.

I am looking for suggestions or comments on building an engine for the car that would be fun to drive on the street and not be a slouch. Pump gas, automatic, and of course the six pack setup. I had been thinking about the 440 Source 512 rotating kit with the stealth heads, roller rockers, upgraded springs, locks, retainers, and headers. It would be a power brake/steering car so vacuum at idle would be a factor. Not sure what cam to go with or converter to work with the six pack. 6000rpm, 3:55 gear. All the parts except the block would be new.

I searched to see if someone else has done a stealth head six pack stroker build and didn't see one. I apologize if someone did and I missed it. I no longer have my engine builder I have used in the past so I don't have one set yet. I have to get my engine torn apart and the block checked and see if I have a good starting point.

In addition to wondering about the cam and converter choice, do any of you do builds like I am describing here?
 
I will let you know in about a month. I built a 440 + 6 using the 440 Source 512 stroker kit and stealth heads. Using a Mr Six Pack cam designed especially for a 512 stroker. I didn’t do anything to the heads except have everything checked out at the machine shop even though they were new. Running roller rockers and a dual point distributor. So basically a stock 512 :D

9C7B2D15-755A-481B-BDF3-D02EAF728965.jpeg
 
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tnfastback said:
I will let you know in about a month. I built a 440 + 6 using the 440 Source 512 stroker kit and stealth heads. Using a Mr Six Pack cam designed especially for a 512 stroker.

View attachment 987852
Click to expand...

I’ll be watching your progress x2 as I’m building a 470B/6-pack myself. Block is currently at the machine shop. Leaning towards the purple shaft 484 on the 114 centerline or the 528 solid (I have Crane ductile rockers).

I haven’t finalized my cam choice yet, but I’m using stealth heads also. Have a 10” converter, with a 4:10 SG.
 
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tnfastback said:
I will let you know in about a month. I built a 440 + 6 using the 440 Source 512 stroker kit and stealth heads. Using a Mr Six Pack cam designed especially for a 512 stroker. I didn’t do anything to the heads except have everything checked out at the machine shop even though they were new. Running roller rockers and a dual point distributor. So basically a stock 512 :D

View attachment 987852
Click to expand...
Sweet! Let me know how it turns out! Is the cam a solid or hydraulic? Did you end up with about 10.5 CR?
 
Hydraulic Cam and if I remember correctly We ended up around 10.2 compression ratio as I used a little thicker head gasket. I used Cometic head gaskets as I have had good luck with in the past. They are also reusable if the heads ever have to be pulled.
 
jphemi70 said:
My son and I are restoring a 1970 RR. We got a 440 to use the block to make a 440+6 for the street.

I am looking for suggestions or comments on building an engine for the car that would be fun to drive on the street and not be a slouch. Pump gas, automatic, and of course the six pack setup. I had been thinking about the 440 Source 512 rotating kit with the stealth heads, roller rockers, upgraded springs, locks, retainers, and headers. It would be a power brake/steering car so vacuum at idle would be a factor. Not sure what cam to go with or converter to work with the six pack. 6000rpm, 3:55 gear. All the parts except the block would be new.

I searched to see if someone else has done a stealth head six pack stroker build and didn't see one. I apologize if someone did and I missed it. I no longer have my engine builder I have used in the past so I don't have one set yet. I have to get my engine torn apart and the block checked and see if I have a good starting point.

In addition to wondering about the cam and converter choice, do any of you do builds like I am describing here?
Click to expand...

It think there are a bunch of street 500 cuin motors out there like you describe. I don't think the six pack is the key criteria you should be focused on. Another words, any pump gas, decent idle 500 cuin motor with Stealth/Edelbrock/Sidewinder heads will be close enough.

It is almost impossible to not make 525 hp with 500cuin and aluminum heads. If you're looking for 600 hp, then the details start to matter, and of course, cost goes up.

If you already have a converter, try it before you buy one.
 
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This is my motor which was build by a reputable Mopar guy in 2007
440 bored .030=446
KB 237 pistons .003 deck height
Forged crank .010 under
Eagle 4340 H-beam rods
Comp is 10.25:1
Eddy heads 84cc with stage 1 and bowl blend
Straightline Cam 234/[email protected] 540/525 solid with 112 lsa (4* built in) installed straight up
6-pack aluminum manifold with stock carbs. (Using ProMax stuff)
Comp pro-magnum 1.5 rockers with 3/8 Smith Bros. pushrods
TTI 1 7/8 headers with 3" X cross-over exhaust to the tips
MSD 8546 dist.
MP MSD 6AL
Dana 60 with 3:54

It was dynoed at 491hp/535 torque at the crank. 7 years ago on a chassis dyno, it did 399 at the rear wheels and 448 torque.
13.01 @107.93, 2.08 60', street tires spinning all the way down
 
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jphemi70 said:
My son and I are restoring a 1970 RR. We got a 440 to use the block to make a 440+6 for the street.

I am looking for suggestions or comments on building an engine for the car that would be fun to drive on the street and not be a slouch. Pump gas, automatic, and of course the six pack setup. I had been thinking about the 440 Source 512 rotating kit with the stealth heads, roller rockers, upgraded springs, locks, retainers, and headers. It would be a power brake/steering car so vacuum at idle would be a factor. Not sure what cam to go with or converter to work with the six pack. 6000rpm, 3:55 gear. All the parts except the block would be new.

I searched to see if someone else has done a stealth head six pack stroker build and didn't see one. I apologize if someone did and I missed it. I no longer have my engine builder I have used in the past so I don't have one set yet. I have to get my engine torn apart and the block checked and see if I have a good starting point.

In addition to wondering about the cam and converter choice, do any of you do builds like I am describing here?
Click to expand...

I'd stick to .030 over (505") if you can, thicker cylinder walls are worth more than the a few more cubes. Others can recommend a cam, but I'd go solid flat tappet. Shoot for 10.5 CR, my 500" motor ran fine on pump 92 with measured 10.5 CR. Put a 9 1/2" Lupo Dynamic converter in it Be sure to have the heads checked by a good machine shop before assembly. I hope the Source heads are better quality now than what some were a few years ago. Get good rockers too. I like my Hughes rocker setup. Not cheap but seem real good.
 
I've got 2 512 motors but they are built by stroking 400 blocks. .much thicker cylinder walls. .ive got stealth heads on one and sidewinder on the other. .870 4 barrel carb on each motor. .540 cam I believe
 
It's beyond awesome. .pump gas also. .power brakes work great. .one is in my 74 charger se. .i have a manual valve body 727 trans in it with 3.91 gears. .roast the tires all the way to 55 mph. .my 2nd 512 is in my 72 charger se. .we just started that car 2 days ago for the first time, so it hasn't been out yet
 
The 500" motor that came in my Satellite had Comp XS 274S (236/[email protected], 502/511), EDE RPM's, 10.5 actual CR, 850DP/Torker, 505 HP/603 ft/lbs. Changed to old Cam Dynamic 260/265* @.050, 565/585 solid. Estimate that added about 75 HP. Still very streetable. 10" converter & 4.10's and 3750#'s.
 
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With a six pack, I would look at a solid cam with about 112 lsa for street friendly. I would look into a Dwayne Porter cam.
 
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Since the bulk of the build is already determined by the basic combo, the biggest factors in hp output will end up being how good the heads are, and how hot of a cam you can tolerate.

Juggling those two things around can easily result in a 100hp swing.

Untouched Stealth heads and a mild-ish hyd cam, vs TF240’s and a healthy solid cam can end up with 100hp difference in output(or more).

I have a couple of customers who have built a number of these 6bbl strokers...... from mild to wild(ish).

Just be realistic about how the motor will be used, and what your expectations are.
 
66Satellite47 said:
The 500" motor that came in my Satellite had Comp XS 274S (236/[email protected], 502/511), EDE RPM's, 10.5 actual CR, 850DP/Torker, 505 HP/603 ft/lbs. Changed to old Cam Dynamic 260/265*, 565/585 solid. Estimate that added about 75 HP. Still very streetable. 10" converter & 4.10's and 3750#'s.
Click to expand...
PRHeads said:
Since the bulk of the build is already determined by the basic combo, the biggest factors in hp output will end up being how good the heads are, and how hot of a cam you can tolerate.

Juggling those two things around can easily result in a 100hp swing.

Untouched Stealth heads and a mild-ish hyd cam, vs TF240’s and a healthy solid cam can end up with 100hp difference in output(or more).

I have a couple of customers who have built a number of these 6bbl strokers...... from mild to wild(ish).

Just be realistic about how the motor will be used, and what your expectations are.
Click to expand...

Thanks for the suggestions. I noticed that 440 Source does not presently offer a ported version of their stealth head. I like that the head looks like the cast iron, but wonder how much HP is there by porting. I think they used to cost about $1K more for porting. I guess I should look up the magazine article where they have been tested. Thanks again!
 
I'm sure quality porting is worth a fair amount of power. Stock Source heads are better than a stock iron head, but bowl work/valve job and a bit in the pushrod lump will sure help.
 
tnfastback said:
I will let you know in about a month. I built a 440 + 6 using the 440 Source 512 stroker kit and stealth heads. Using a Mr Six Pack cam designed especially for a 512 stroker. I didn’t do anything to the heads except have everything checked out at the machine shop even though they were new. Running roller rockers and a dual point distributor. So basically a stock 512 :D

View attachment 987852
Click to expand...
Were you able to use stock valve covers with the roller rockers you used? Are the rockers 440 Source?
 
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