Engine HP query

[C500]

hey all... I have a 440/727 '69 and recently Dyno tuned with 330 HP at the rear wheels. Any idea how much HP this measures at the crank? Engine balanced, with build details below.

CAM: Crower Hydraulic (271HDP) Flat tappet, Advertised Duration 271/284, Lift .486/.496 Part number: 32242
HEADS: 440 Source 'stealth heads', ported
PISTONS: JE / SRP Flat top, Forged aluminium, 2.062" compression distance, Part number 213455
PISTON RINGS: JE, matching pistons above
VALVE SPRINGS: Comp Cams, Single outer springs, Part number 911
CARBURETOR: ProForm 750 cfm, Mechanical Secondary, Street series, Part number 67213
OIL PUMP: Melling, Part number M63
FUEL PUMP: New Carter
WATER PUMP: Stock
HARMONIC BALANCER: 440 Source, Elastomer Dampner, Part number 200-1128

New rings, big end, cam and main bearings, ARP rod bolts, Push-rods

Exhaust manifold: stock HP cast iron
Intake Manifold: Edelbrock CH4B, Aluminium dual plane
Ignition: Firecore electronic with new dizzy
New Firecore ignition leads

Heads work: http://www.dodgecharger.com/forum/index.php/topic,126299.0.html

[Challenger340]

Auto W/stall converter ?

HP Manifolds are a huge cork.... what rpm range were you testing within ?

My guess is around 425 HP Flywheel... again, the HP Manifolds/Exhaust can be restrictive above 4,500 rpm.

[C500]

Auto W/stall converter ?

HP Manifolds are a huge cork.... what rpm range were you testing within ?

My guess is around 425 HP Flywheel... again, the HP Manifolds/Exhaust can be restrictive above 4,500 rpm.

thanks for the reply.. no stall converter. The Cam I used was the advice given for those exhaust manifolds...

[metcoll]

I just had mine dynoed on my buddy's dyno..I got 435 rwhp..he dyno supposedly can see hiw much parasitic loss is..according to his dyno I should 530 hp at yhe flywheel..My combo is a 440 with six pack pistons Lunati 240/250 @050 520/547 lift cam rpm heads ported flowing 282 cfm 1/78 tti headers rpm intake 850 dbl  pump holley with MSD ignition.. going through a 727 4200 stall and 4.10 gears..

[C500]

I just had mine dynoed on my buddy's dyno..I got 435 rwhp..he dyno supposedly can see hiw much parasitic loss is..according to his dyno I should 530 hp at yhe flywheel..My combo is a 440 with six pack pistons Lunati 240/250 @050 520/547 lift cam rpm heads ported flowing 282 cfm 1/78 tti headers rpm intake 850 dbl  pump holley with MSD ignition.. going through a 727 4200 stall and 4.10 gears..

Not a massive difference in build to mine, but you have alot more HP... the exhaust manifolds must be a big kicker

[metcoll]

I believe the Rpm intake is a better flowing intake as well as my cam I believe is quite a bit larger..my peak was around 5800 rpm

[BSB67]

Don't get too hung up on dyno numbers.  330 RWHP would be about 415 flywheel.  Maybe more as engine dynos are generally gross hp, and chassis dynos net hp.

Also, not all chassis dynos are the same.  A Mustang dyno will give different results than a DynoJet.

A 330 RWH can run close to 12.99 et in full street trim, I.e. stock converter, 3.23 gear. P225 70 street tires.

[Challenger340]

Just my opinion.....
I wouldn't use a chassis Dyno for anything other than maybe trying to 'tune' ?

But just say'in....
that if you want to know Engine flywheel hp then you need to use an Engine Dyno....
because no 'two' chassis Dyno's I've ever seen give the same numbers ? and I've even seen dramatically different RW numbers on the same Car with no changes on the same Dyno on different days ?

I ain't a fan of the CH4B... Street Dominator is waaay better
HP Manifolds are a cork, but I would still expect 425-430'ish hp at the flywheel w/Street Dominator

[C500]

Just my opinion.....
I wouldn't use a chassis Dyno for anything other than maybe trying to 'tune' ?

But just say'in....
that if you want to know Engine flywheel hp then you need to use an Engine Dyno....
because no 'two' chassis Dyno's I've ever seen give the same numbers ? and I've even seen dramatically different RW numbers on the same Car with no changes on the same Dyno on different days ?

I ain't a fan of the CH4B... Street Dominator is waaay better
HP Manifolds are a cork, but I would still expect 425-430'ish hp at the flywheel w/Street Dominator

Only running the CH4B as it looks like the original cast iron manifold (same reason for using the HP exhaust manifolds), but am only getting 7 inches of vacuum, so brakes not getting enough to work properly. That cam should provide plenty enough vacuum. No leaks visible when spraying soapy water around, so going to try the original intake again back on again. 

[metallicareload99]

something is up, I get at least 9 inHg with 292° advertised duration

[b5blue]

I'd get the car to someone with a 5 gas analyzer. 

[firefighter3931]

Only running the CH4B as it looks like the original cast iron manifold (same reason for using the HP exhaust manifolds), but am only getting 7 inches of vacuum, so brakes not getting enough to work properly. That cam should provide plenty enough vacuum. No leaks visible when spraying soapy water around, so going to try the original intake again back on again. 

The CH4B is fine on a build like that. It is well matched to the flow of a Stealth cylinder head. The CH4B is also significantly superior to the factory manifold so I'd keep it on there.

The low manifold vacuum tells me there is an issue with tuning. That cam pulls 18in of vacuum in a buddy's 440 at 850 rpm. Where do you have the timing set at ? It will want 16*@ idle and 35-36* total. Try advancing the timing to 16 and watch what happens to your idle vacuum and performance ! 

Denis had the same build ; HDP271/Stealth heads/10:1 compression/CH4B/HP exhaust manifolds and it would roast the 275/60 tires for 100ft. 


Ron

[C500]

Only running the CH4B as it looks like the original cast iron manifold (same reason for using the HP exhaust manifolds), but am only getting 7 inches of vacuum, so brakes not getting enough to work properly. That cam should provide plenty enough vacuum. No leaks visible when spraying soapy water around, so going to try the original intake again back on again. 

The CH4B is fine on a build like that. It is well matched to the flow of a Stealth cylinder head. The CH4B is also significantly superior to the factory manifold so I'd keep it on there.

The low manifold vacuum tells me there is an issue with tuning. That cam pulls 18in of vacuum in a buddy's 440 at 850 rpm. Where do you have the timing set at ? It will want 16*@ idle and 35-36* total. Try advancing the timing to 16 and watch what happens to your idle vacuum and performance ! 

Denis had the same build ; HDP271/Stealth heads/10:1 compression/CH4B/HP exhaust manifolds and it would roast the 275/60 tires for 100ft. 


Ron

Hi Ron, good to see you back!! My build was based around Denis's too. Not sure on timing, it was done at the shop. Has been on Dyno at 2 separate places. Neither report shows timing set. Will try your suggestion.

My CH4B had a crack in the base, the engine builders repaired it, but if timing is not the issue, maybe crack has re-opened. Idle is not great, sometimes better than others...so intermittent. Sometimes gets a wheel spinning, sometimes just stumbles and splutters 🥴

[C500]

Hi Ron,

Had an engine builder around. He disconnected the vacuum advance, and set the timing to 18*, was set at 11*. It's definitely running better, and brakes are better. Still getting a stumble on take-off, and not idling very smooth, until warmed up. Any suggestions, or increasing the timing further etc?

[b5blue]

My similar build needed the jets up sized to rid stumble off idle.

[firefighter3931]

My similar build needed the jets up sized to rid stumble off idle.

Timing looks good now. The increased manifold vacuum shows this to be a move in the right direction. As Neal suggests the engine wants more fuel. I would start by upsizing the primary (front) jets by two sizes. If it has #72 jets in the front metering block try going to a #74 and see how it runs.

Cold blooded behavior is normal for these old beasts. Let the engine reach operating temp to guage performance/drivability 


Ron

[b5blue]

I also junked the auto choke and installed a manual pull cable.