Need ideas/help for rebuilding a 440 with HP manifolds and pump gas...

Backpacker · May 19, 2019

Hi guys! So I am starting to restore my 70 Roadrunner (4spd) after many years of storage. The NOM worn out cast crank 383 (yes, cast) that hasn't run in years needs to be replaced with a 440. Don't care about originality but it needs to look somewhat "right". That being said, I am starting completely from scratch with a professional engine builder. The plan is to use the HP manifolds with an H-pipe, run on pump gas, and increase the HP/torque as best as possible while maintaining streetability.

Should I rebuild a pre-73 forged crank 440 with ported 906 heads, get hardened valve seats, and call it a day? Or, rebuild a 73-78 cast crank 440 with ported 452 heads, and have it stroked? Cost wise between the two, it isn't that much different...

Will the HP manifolds kill off any gains made by the increased stroke and porting?

Should I use a painted (single or dual plane) aftermarket intake or just use the later cast iron TQ intake and have the center cut out (like I saw some members have done in a previous post)?

How much more lift/duration (if any) should be added to the cam (keeping the steel rockers) to match these changes without going crazy?

Jerry Hall · May 19, 2019

Again it sounds like you don't know what you want. I had my say in your other thread, but the best advice I saw in that was from @onlyone. If you use his advice make a choice, buy a engine and recoup some of your cash by sending him a core or selling your parts. The price in that post was self explanatory.

67belsat · May 20, 2019

if it was me after market heads hyper pistons and a dual plane intake with a hydraulic roller cam I would run headers myself put stock manifolds on shelf your engine builder will help you out.

wyrmrider · May 20, 2019

First regular, OR premium pump gas not race gas
in otherwords nail down your usage and driving style and compression
with either of the stock heads you need the KB quench dome pistons to get any quench otherwise you have problems with pump gas and timing and you will run hotter than need to
the other option is 915 heads or aftermarket closed chamber heads and "D" dish piston
headers do make a big difference especially in top end HP- but I like my stereo and run cleaned up HP manifolds
cam will depend not only on compression but on converter and gears and how you want to drive it
you need to determine your desired rpm range and how broad a torque curve or how peaky (which works better with high compression)
use 256-262 Lunati voodo as your strawman for a lower compression street build, daily driver - not sat night special
late iron manifold and Thermoquad works best but heavy
AVS second choice

Backpacker · May 20, 2019

wyrmrider said:
First regular, OR premium pump gas not race gas
in otherwords nail down your usage and driving style and compression
with either of the stock heads you need the KB quench dome pistons to get any quench otherwise you have problems with pump gas and timing and you will run hotter than need to
the other option is 915 heads or aftermarket closed chamber heads and "D" dish piston
headers do make a big difference especially in top end HP- but I like my stereo and run cleaned up HP manifolds
cam will depend not only on compression but on converter and gears and how you want to drive it
you need to determine your desired rpm range and how broad a torque curve or how peaky (which works better with high compression)
use 256-262 Lunati voodo as your strawman for a lower compression street build, daily driver - not sat night special
late iron manifold and Thermoquad works best but heavy
AVS second choice

Premium pump gas, so I am guessing 9-9.5 to 1 compression.
"Daily driver" driven with a lead foot. 4 speed with probably a 3.23 or 3.55 gear.
A middle RPM range with a flatter curve since I am assuming that the HP manifolds will restrict the airflow on the top end.

Jerry Hall · May 20, 2019

Backpacker said:
Premium pump gas, so I am guessing 9-9.5 to 1 compression.
"Daily driver" driven with a lead foot. 4 speed with probably a 3.23 or 3.55 gear.
A middle RPM range with a flatter curve since I am assuming that the HP manifolds will restrict the airflow on the top end.

Thanks, you now have a baseline on what you want. I would go with a basically stock 6-pack specification build. Your exhaust manifolds work great, and you can use a stock type 4bbl intake and about a 750 cfm carburetor of your choice. With your compression between 9.5 & 10 it should be able to run 91-93 octane pump gas. There should be a lot of input on exact cam, pistons, etc. I like the idea of the 915 heads and the dished pistons to your desired compression. You should end up with no less than the 375 HP and as much as 425 HP. Little, but costly things like port work, port matching intake and exhaust wi

Jerry Hall · May 20, 2019

will all help your numbers on HP and torque.

IQ52 · May 20, 2019

Backpacker said:
Hi guys! So I am starting to restore my 70 Roadrunner (4spd) after many years of storage. The NOM worn out cast crank 383 (yes, cast) that hasn't run in years needs to be replaced with a 440. Don't care about originality but it needs to look somewhat "right". That being said, I am starting completely from scratch with a professional engine builder. The plan is to use the HP manifolds with an H-pipe, run on pump gas, and increase the HP/torque as best as possible while maintaining streetability.

Should I rebuild a pre-73 forged crank 440 with ported 906 heads, get hardened valve seats, and call it a day? Or, rebuild a 73-78 cast crank 440 with ported 452 heads, and have it stroked? Cost wise between the two, it isn't that much different...

Will the HP manifolds kill off any gains made by the increased stroke and porting?

Should I use a painted (single or dual plane) aftermarket intake or just use the later cast iron TQ intake and have the center cut out (like I saw some members have done in a previous post)?

How much more lift/duration (if any) should be added to the cam (keeping the steel rockers) to match these changes without going crazy?

So if your are using a professional engine builder and he cannot answer these questions, you done got the wrong engine builder!

wyrmrider · May 21, 2019

906 or 452 or 915 heads better plan on ex seats- they may had a few valve jobs and be through the factory "induction or electro hardening"
you will need guides I recommend spiral inside to hold some oil now compare your costs with aftermarket heads
the 2.14 x 1.81 size works one and gives a fresh intake seat
run factory rockers if under .525 lift or else iron rockers
roller rockers require the B3 shaft relocation procedure/ kit or geometry is off
you might consider a solid lifter cam and lifters- not much of a PITA and provide proven benefits
I have never had much luck running stock 6 pack pistons and iron heads one today's premium pump gas
with stock open chamber heads KB 184 or KB 236 depending on the compression you want
KB 238 can be made to work with closed chamber 915 with a little dome massaging
figure out what cc your heads will be - remember factory numbers are for "blueprinted" minimum spec heads- they are usually quite a bit larger
and if you open up your chambers to add larger valves you may add 5cc easy

wyrmrider · May 22, 2019

IQ there are a lot of professional engine builders who cannot build a mopar-
so op find a qualified MOPAR engine builder who does something besides bracket/ race motors
9 to 9.5 with tight quench and iron heads
slightly more with aluminum heads
not 6 pack advertised compression or even Magnum advertised compression especially with open chamber heads and no quench
I'd rather run a solid cam than a HR but a good HYd should work for your build
with those gears and no converter for torque multiplication you want a big fat "engine masters" type torque curve not a ricky bracket racer type torque curve
so short duration and fat lift curve-- depending on head and porting no use high lift with stock heads and you will need to limit distributor and tune tune tune
too bad that hot rod article did not give curves just peak HP and torque
https://www.hotrod.com/articles/mopar-performance-purple-shaft-camshaft/
all of these are bracket cams or would require lower gears
IQ are you still building motors or retired as I am?

Challenger340 · May 25, 2019

Backpacker said:
Hi guys! So I am starting to restore my 70 Roadrunner (4spd) after many years of storage. The NOM worn out cast crank 383 (yes, cast) that hasn't run in years needs to be replaced with a 440. Don't care about originality but it needs to look somewhat "right". That being said, I am starting completely from scratch with a professional engine builder. The plan is to use the HP manifolds with an H-pipe, run on pump gas, and increase the HP/torque as best as possible while maintaining streetability.

Should I rebuild a pre-73 forged crank 440 with ported 906 heads, get hardened valve seats, and call it a day? Or, rebuild a 73-78 cast crank 440 with ported 452 heads, and have it stroked? Cost wise between the two, it isn't that much different...

Will the HP manifolds kill off any gains made by the increased stroke and porting?

Should I use a painted (single or dual plane) aftermarket intake or just use the later cast iron TQ intake and have the center cut out (like I saw some members have done in a previous post)?

How much more lift/duration (if any) should be added to the cam (keeping the steel rockers) to match these changes without going crazy?

just my opinions, no wars wanted.
1.) Your choice between the pre '73 Forged or later cast crank engine selection boils down to the 4 spd. While the cast Cranks are pretty darn tough, depending upon traction/driveline, and how hard it will actually get hit is cumulative..... the Cast Cranks more prone over time.
my default if you have a CHOICE..... is to use the Forged Crank in the later 70's Block with the wider Crank Thrust Bearing Flange, and the #4 main Cap will also thank you for the "Internal" balance vrs the Cast Crank External balance.

2.) Seeing as how both of your Cylinder Head choices for rebuilding are Cast Iron(906 vrs 452), and yet you are talking/planning Porting on both... with hardened seats in the 906's.... ostensibly under the criterion of keeping things looking "right" underhood ?
Doing either of the above done PROPERLY, inclusive of Labor and Parts, you have very quickly exceeded pricewise the cost of buying the aftermarket STEALTH aluminum head, and painting it to appear stock !
The Stealth's OOTB will Flow FAR MORE than anything you are going to do to either your 906 or 452's ! and they will provide sorely needed QUENCH on the Pump Gas.
And remember that by the time you BUY:
Valves, Valve Springs, V/Locks, V/Retainers, V/Seals
and PAY...
To have the Heads rebuild PROPERLY with a Hone-Fit Bronze V/Guide so you can run an HP Valve Seat Grind to take advantage of any Porting...
Machine for V/Springs
Machine for V/Seals
Install Exh Seats
Surfacing
FORGET IT !
Buy the STEALTH's and add the 10* V/Locks and Retainers.

3.) Yes, HP Manifolds will Kill power otherwise available that ANY Engine would make with the free'er breathing Headers. Worst case we've seen is we dumped 75hp off a otherwise 585hp Hyd Roller 440 with the Dyno headers..... and yes, we used STEALTH's albeit we Ported/Painted them to maintain factory appearing underhood.
And Yes, any Cast Iron factory Intake is also restrictive compared to pretty much anything aftermarket.
Hood clearance being an issue.... default to the Holley Street Dominator 300-14, it is a very low-rise single plane, fits underhood, and delivers good power with decent throttle response down low as well.

4.) Don't go nuts on Cam overlap, keep things sane, I would suggest 112 to 114* lsa on anything mid/high 220's @ .050 Intake pattern on a 440, 6-8 larger on the Exhaust.

With some attention to detail in the build, careful Piston selection(either SRP or the ICON 9953 for cheaper 5/64 rings comes to mind for the stock rod 440 ), shouldn't be a problem realizing 450 hp @ 5,000 rpm with the hp manifolds with 525 Ft/Lbs quite low/ very flat curve.

BSB67 · May 25, 2019

Challenger340 said:
just my opinions, no wars wanted.
1.) Your choice between the pre '73 Forged or later cast crank engine selection boils down to the 4 spd. While the cast Cranks are pretty darn tough, depending upon traction/driveline, and how hard it will actually get hit is cumulative..... the Cast Cranks more prone over time.
my default if you have a CHOICE..... is to use the Forged Crank in the later 70's Block with the wider Crank Thrust Bearing Flange, and the #4 main Cap will also thank you for the "Internal" balance vrs the Cast Crank External balance.

2.) Seeing as how both of your Cylinder Head choices for rebuilding are Cast Iron(906 vrs 452), and yet you are talking/planning Porting on both... with hardened seats in the 906's.... ostensibly under the criterion of keeping things looking "right" underhood ?
Doing either of the above done PROPERLY, inclusive of Labor and Parts, you have very quickly exceeded pricewise the cost of buying the aftermarket STEALTH aluminum head, and painting it to appear stock !
The Stealth's OOTB will Flow FAR MORE than anything you are going to do to either your 906 or 452's ! and they will provide sorely needed QUENCH on the Pump Gas.
And remember that by the time you BUY:
Valves, Valve Springs, V/Locks, V/Retainers, V/Seals
and PAY...
To have the Heads rebuild PROPERLY with a Hone-Fit Bronze V/Guide so you can run an HP Valve Seat Grind to take advantage of any Porting...
Machine for V/Springs
Machine for V/Seals
Install Exh Seats
Surfacing
FORGET IT !
Buy the STEALTH's and add the 10* V/Locks and Retainers.

3.) Yes, HP Manifolds will Kill power otherwise available that ANY Engine would make with the free'er breathing Headers. Worst case we've seen is we dumped 75hp off a otherwise 585hp Hyd Roller 440 with the Dyno headers..... and yes, we used STEALTH's albeit we Ported/Painted them to maintain factory appearing underhood.
And Yes, any Cast Iron factory Intake is also restrictive compared to pretty much anything aftermarket.
Hood clearance being an issue.... default to the Holley Street Dominator 300-14, it is a very low-rise single plane, fits underhood, and delivers good power with decent throttle response down low as well.

4.) Don't go nuts on Cam overlap, keep things sane, I would suggest 112 to 114* lsa on anything mid/high 220's @ .050 Intake pattern on a 440, 6-8 larger on the Exhaust.

With some attention to detail in the build, careful Piston selection(either SRP or the ICON 9953 for cheaper 5/64 rings comes to mind for the stock rod 440 ), shouldn't be a problem realizing 450 hp @ 5,000 rpm with the hp manifolds with 525 Ft/Lbs quite low/ very flat curve.

Nice response Bob.

wyrmrider · May 25, 2019

nice response Bob
agree on the quench- get it one way or the other 902-905 452 etc takes special pistons as I posted earlier
although a caveat on the stock manifold
except for weight it works better than most early aftermarket aluminum ones and TQ works better than
you will need less exhaust duration withheaders
you do not need roller tip rockers wth this build- spend elsewhere
early forged crank will not use the extra thrust - late crank late thrust is best but early can work if you chamfer the bearings parting lines to the rear
and drill the feed through th thrust into the main feed .040 works do not ride the clutch and careful clutch selection in any case
if you do not already have a crank and pistons think stroker kit

Need ideas/help for rebuilding a 440 with HP manifolds and pump gas...

Backpacker

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Jerry Hall

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67belsat

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wyrmrider

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Backpacker

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Jerry Hall

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Jerry Hall

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IQ52

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wyrmrider

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wyrmrider

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Challenger340

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BSB67

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wyrmrider

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