440 Rear-Wheel HP Numbers Seem Off 30-40%

[Fury1969WI]

I have the Comp 480/280 cam in my 440 with 452 heads (bone-stock NOS score) and MP dual plane intake and HP manifolds, 2.5" TTI exhaust. Open air cleaner. 0.030 over (4.350 bore) with JE Pistons. Edlebrock 750 with manual choke.

Rear wheel dyno with bent rim and running too rich was 204 RWHP.

I also think i'm off because with the added 3.55 suregrip i can't spin the tires. I'm running 15" cop rims with 255 BFG Radial TA. B&M shift kit and 1800 RPM stall converter. With the 2.76 single i could get tire spin from a rolling start. That's anecdotal evidence because i think i had skinny tires when running the 2.76 open.

I feel like i'm missing about 80-90 RWHP.

Thinking back, I could never get the full 30 degrees advance (think i'm at 26-28 degrees) timing without detonation or pinging. ???

I bought the carb tuning kit to jet-down the carb too address the AF issue; running rich - about 12.5:1 if memory serves (the dyno with AF test was years ago - before i took car apart in 2008).

I'm reassembling the car after my restification so at this point i'm outta cash so want to squeeze what i can out of this setup.

Am i missing a *$#&%$-ton of HP? I was thinking i'd built something greater than the 440 Magnum specs so was expecting nearly 300 RWHP.
I can live with the car as-is but if i can figure something out on the small parts / tune end of things i'd be one happy camper.

1) I have been really disappointed with the 204 RWHP number, however, i don't know. The difference from the 318 makes it easy to live with - if "it is what it is." Any real-world numbers from a stock/+0.30 440?
2) How much HP is hiding in the timing? How do i correct this issue? New distributor? I put the lighter springs in and filed for max advance (per Mopar Action tech articles).
3) What is the impact of the overly rich Air-Fuel ratio? I would think this would be more of an economy vs. HP issue (unless plugs are fouled - they were not - browner than they should have been but OK-ish).
4) Is the dual-plane intake a killer? I wanted my build, c-body, for torque so purposely went dual-plane.

I realize drive-train and engine combos are like reading tea-leaves but any thoughtful experience you could share on how to squeeze the performance i think i should have out of this combo appreciated.

 

[70bigblockdodge]

Have to start at basics verify TDC, make sure throttle is opening 100% with pedal, set timing at 35 BTDC @3500rpm, connect a vacuum guage you can read from inside at speed. I am going to guess something is not right with timing and the secondaries are not coming on all the way, the vacuum guage should show vacuum at higher rpm, try with and without air cleaner.

 

[C Body Bob]

Agree timing should be checked. As in timing chain installed correctly What are the RPM builds. What Dave said above. A 440 with that cam should build power with RPM increase well past 5K. My 318 rear wheels 235 with a lot les cam & it pulls hard all the way to 5K

 

[70bigblockdodge]

12.5 AF at wot is good. You have something in the timing are you sure your on number one wire, don't laugh I've done it.

 

[WorkerBee]

Like Dave said, set the timing at 35 BTDC @3500rpm with the vacuum hose disconnected at the distributor and plug the hose.
Another thing too try is to take the car out for a drive with the vacuum advance disconnected and the hose plugged. It shouldn't detonate like this. Let us know the results.

 

[Fury1969WI]

Have to start at basics verify TDC, make sure throttle is opening 100% with pedal, set timing at 35 BTDC @3500rpm, connect a vacuum guage you can read from inside at speed. I am going to guess something is not right with timing and the secondaries are not coming on all the way, the vacuum guage should show vacuum at higher rpm, try with and without air cleaner.

I have the engine in the car but not ready to fire yet. I could never get 35 degrees without pinging/detonation before. Something is wrong with timing, but what? Distributors are a know achiles heel, should i just can the 40+ year old piece and pony-up for something new? but what??

If i can get 35 degrees at 3,000 RPM that's where i need to be (per Mr. Ehrenberg).

That might be hiding 20-30 ponies but i'm still coming-up short...

 

[Fury1969WI]

12.5 AF at wot is good. You have something in the timing are you sure your on number one wire, don't laugh I've done it.

Yes, never underestimate (overlook?) the obvious! Yes, i think ideal is 12:1 or 12.1:1.0 so AF is not the major issue, just a tweak probably.

 

[WorkerBee]

I have the engine in the car but not ready to fire yet. I could never get 35 degrees without pinging/detonation before. Something is wrong with timing, but what? Distributors are a know achiles heel, should i just can the 40+ year old piece and pony-up for something new? but what??

If i can get 35 degrees at 3,000 RPM that's where i need to be (per Mr. Ehrenberg).



That might be hiding 20-30 ponies but i'm still coming-up short...

I suspect too light of advance springs for a heavy car and you probably need to back off the advance in the vacuum advance.

 

[Fury1969WI]

Agree timing should be checked. As in timing chain installed correctly What are the RPM builds. What Dave said above. A 440 with that cam should build power with RPM increase well past 5K. My 318 rear wheels 235 with a lot les cam & it pulls hard all the way to 5K

I wish i had the full set of data from the dyno runs, i only have scrap of paper with some graphs. It revs easily to well over 5k. I am looking for more launch/snarf.

 

[65Fury440]

What kind of ignition are you running?

 

[MN72Fury]

Sounds like a nice car

How is the 3.55 gearing, is it still o.k. to go 70-75 without winding out the motor, I am also considering upgrading from my 2.76?

 

[11secondC]

Everyone has covered the timing, definitely needs to be checked.

AF numbers seem suspect, never seen a stock Edelbrock AFB be rich, they are factory setup for your belly button sbc 350's...always had to jet up and change metering rods to get them to play nice with any sort of cam on my big blocks. Finally tossed it for a Holley and haven't looked back.

If those check out, it still has too much cam for the rest of the combo/car.

Is this a fresh build? How many miles on the block? You said the heads were "stock", 452's while having the hardened seats and the big exhaust valve, have huge chambers compared to the early 915 heads and compression might not be where you think it is.

If you want to keep the cam, step up the converter to something in the 2500 range, and the car really needs 3.91's and a decent dual plane to make power. RPM works wonders.

I ran the MP484, which is a touch bigger than your cam, in my '67 VIP with a worn out 413, 3.91's with SureGrip and a 2400 stall no name converter, did have headers but stock '62 heads, and it would melt 295/50 BFG's at will anywhere in low gear.

If your willing to change cams, I really like the 268 Comp for better than stock power but still retains the driveability without have to go to anything bigger than a hemi converter and 3.23's.

 

[cantflip]

I have the Comp 480/280 cam in my 440 with 452 heads (bone-stock NOS score) and MP dual plane intake and HP manifolds, 2.5" TTI exhaust. Open air cleaner. 0.030 over (4.350 bore) with JE Pistons. Edlebrock 750 with manual choke.

Rear wheel dyno with bent rim and running too rich was 204 RWHP.

I also think i'm off because with the added 3.55 suregrip i can't spin the tires. I'm running 15" cop rims with 255 BFG Radial TA. B&M shift kit and 1800 RPM stall converter. With the 2.76 single i could get tire spin from a rolling start. That's anecdotal evidence because i think i had skinny tires when running the 2.76 open.

I feel like i'm missing about 80-90 RWHP.

Thinking back, I could never get the full 30 degrees advance (think i'm at 26-28 degrees) timing without detonation or pinging. ???

I bought the carb tuning kit to jet-down the carb too address the AF issue; running rich - about 12.5:1 if memory serves (the dyno with AF test was years ago - before i took car apart in 2008).

I'm reassembling the car after my restification so at this point i'm outta cash so want to squeeze what i can out of this setup.

Am i missing a *$#&%$-ton of HP? I was thinking i'd built something greater than the 440 Magnum specs so was expecting nearly 300 RWHP.
I can live with the car as-is but if i can figure something out on the small parts / tune end of things i'd be one happy camper.

1) I have been really disappointed with the 204 RWHP number, however, i don't know. The difference from the 318 makes it easy to live with - if "it is what it is." Any real-world numbers from a stock/+0.30 440?
2) How much HP is hiding in the timing? How do i correct this issue? New distributor? I put the lighter springs in and filed for max advance (per Mopar Action tech articles).
3) What is the impact of the overly rich Air-Fuel ratio? I would think this would be more of an economy vs. HP issue (unless plugs are fouled - they were not - browner than they should have been but OK-ish).
4) Is the dual-plane intake a killer? I wanted my build, c-body, for torque so purposely went dual-plane.

I realize drive-train and engine combos are like reading tea-leaves but any thoughtful experience you could share on how to squeeze the performance i think i should have out of this combo appreciated.

I have the engine in the car but not ready to fire yet. I could never get 35 degrees without pinging/detonation before. Something is wrong with timing, but what? Distributors are a know achiles heel, should i just can the 40+ year old piece and pony-up for something new? but what??

If i can get 35 degrees at 3,000 RPM that's where i need to be (per Mr. Ehrenberg).

That might be hiding 20-30 ponies but i'm still coming-up short...

Yes, never underestimate (overlook?) the obvious! Yes, i think ideal is 12:1 or 12.1:1.0 so AF is not the major issue, just a tweak probably.

I just have to ask... are you still working from 2008 data on an unfired rebuild? If so, get her broke in and then try a new set of numbers.

 

[70bigblockdodge]

Agree with 11second never have seen a eddy rich at WOT and it is not. Also another thought is your distributor working properly, mechanical advance is not stuck or vacuum advance is coming on at something like 2" just a couple of things to check.

 

[heyoldguy]

Which JE pistons are you running? I mean really, 26-28 degrees maximum to prevent detonation? What octane fuel are you using? If you are running the stock points distributor, it is time to upgrade to a new modern distributor and ignition box.

 

[70bigblockdodge]

Which JE pistons are you running? I mean really, 26-28 degrees maximum to prevent detonation? What octane fuel are you using? If you are running the stock points distributor, it is time to upgrade to a new modern distributor and ignition box.

I will take this moment to get some free advice. What would be a good choice for a ignition upgrade for a street and strip car. I don't have a problem yet because the car is not running but if I did want to up grade without breaking the bank. Currently running a old mid eighties Mopar performance dist all in by 2500 and was a orange box but used it on another car so I was going to get a chrome box, need a upgrade for my coil also I don't think I am putting the big yellow super coil back in. Let the suggestions fly.

 

[11secondC]

Was running the MP dist with a reworked curve and Crane HI-6 + matching coil. Locked out the dist when I switched to E85. If I had to start fresh would be the MSD gear.

 

[Fury1969WI]

What kind of ignition are you running?

Mopar electronic with orange box. Original 1973 distributor with some rework, lower collar, advance curve, lighter springs all per Mopar Action Tech.

I am serious considering this distributor; full sealed bearings, stock cap/rotor, wiring hook-up.

http://www.manciniracing.com/maravaadeldi.html (Mancini Racing - Firecore);

[h=1]ireCore Vacuum Advance Electronic Distributor[/h]Item #: CWS-90432
Write a Review


Price: $165.95

 

[Fury1969WI]

Love the gear.

This from 8 years ago, but i think 65-70 MPH was 1600 RPM, maybe a little higher, 1800 tops. I usually like the back roads and 55 cruising scene.

I would love to put an overdrive and 3.91 (like my 2012 Ram) but that's not gonna happen this time 'round.

Sounds like a nice car

How is the 3.55 gearing, is it still o.k. to go 70-75 without winding out the motor, I am also considering upgrading from my 2.76?

 

[Fury1969WI]

see my comments below, in ​red

Everyone has covered the timing, definitely needs to be checked.

AF numbers seem suspect, never seen a stock Edelbrock AFB be rich, they are factory setup for your belly button sbc 350's...always had to jet up and change metering rods to get them to play nice with any sort of cam on my big blocks. Finally tossed it for a Holley and haven't looked back

I'm using a re-man eddy 750 with manual choke, new-ish back when i built the engine 15 years ago (shocked it's been that long!).

If those check out, it still has too much cam for the rest of the combo/car.

Is this a fresh build? How many miles on the block? You said the heads were "stock", 452's while having the hardened seats and the big exhaust valve, have huge chambers compared to the early 915 heads and compression might not be where you think it is.

Complete rebuild in 2000, installed/fired 2005, put on about 3,500 miles before tearing car apart in winter 2007/2008.

Compression was estimated (measured?) at 9.74:1 as follows;

+ Head/combustion chamber; 88.5
+ Gasket 9.0
+ Deck 4.0
+ Valve Pocket 3.0
Total 104.5 cc

Cylinder displacement at 912.9 cc (4.350 bore, stock crank).

912.9 + 104.5 = 1017.4
Compression 1017.4 (all)/104.5 (compressed) = 9.736



If you want to keep the cam, step up the converter to something in the 2500 range, and the car really needs 3.91's and a decent dual plane to make power. RPM works wonders.

Running the Mopar 4876870 converter (1900-2100 stall). is the Mopar M1 (4529118) intake that bad compared to RPM?

I ran the MP484, which is a touch bigger than your cam, in my '67 VIP with a worn out 413, 3.91's with SureGrip and a 2400 stall no name converter, did have headers but stock '62 heads, and it would melt 295/50 BFG's at will anywhere in low gear.

If your willing to change cams, I really like the 268 Comp for better than stock power but still retains the driveability without have to go to anything bigger than a hemi converter and 3.23's.