422 dyno fail

-
I never said it’s stock....... and I specifically mentioned it’s 5ci bigger than the OP’s 422.
It’s a useful comparative tool if you’re open minded.

Headers or manifolds.... which is better?
Ported stock intake or aftermarket single plane?
Stock air filter(has to be in place) or not?
If you changed out those items on the Duster engine would it make more or less power?
And the heads on that particular engine flow less than the OP’s, so that’s not why that one makes good power.

Same can be said for the Stocker comparison.
It has less of everything than the OP’s combo other than cam duration.
Was less flow, way less lift, stock intake...... makes way more power.

When you race in classes where you have to stay within the rules....... you find ways to make power that don’t include being able to buy a bunch of the latest stuff out of the Summit catalog.

My friends stocker has been almost 129@3300lbs at an NHRA event(weighed and fuel check after every pass) with heads that flow 220.
he also has a 350 Pontiac engine for that car that’s been 123, with small valve heads that flow 200.
 
PRH said:
I never said it’s stock.
It’s a useful comparative tool if you’re open minded.

Headers or manifolds.... which is better?
Ported stock intake or aftermarket single plane?
Stock air filter(has to be in place) or not?
If you changed out those items on the Duster engine would it make more or less power?
And the heads on that particular engine flow less than the OP’s, so that’s not why that one makes good power.

Same can be said for the Stocker comparison.
It has less of everything than the OP’s combo other than cam duration.
Was less flow, way less lift, stock intake...... makes way more power.

When you race in classes where you have to stay within the rules....... you find ways to make power that don’t include being able to buy a bunch of the latest stuff out of the Summit catalog.

My friends stocker has been almost 129@3300lbs at an NHRA event(weighed and fuel check after every pass) with heads that flow 220.
Click to expand...
We will just agree to disagree......I have had many friends over the years that ran in different classes of stock eliminator and although they didn't tell me every little top secret detail , they did tell me enough to know that there is a lot of high tech, high dollar to make it happen cheating or bending of the rules as to how some would want to phrase it going on especially with the fastest cars in each class.......also am very good friends with another top tier head and intake guy who has his own business who has done work for Dudek and many others over the years in the F.A.S.T. class and he went into detail what goes into those engines as I considered fielding a car myself but ultimately decided against it due to my location.
 
Several responses to this thread were raising some theoretical red flags as to why the power was so low.

I’ve tested enough stuff with way less than optimum combinations that made decent power and ran down the track pretty well so that those items don’t look as problematic to me.
 
PRH said:
My point is........ many responses to this thread were raising some theoretical red flag as to why t
Click to expand...
No problem on my end, two people don't have to agree on every single thing and I know who you are and the kind of work you have done over the quite a few years actually, lol, and I respect your knowledge but we just will probably have differing opinions on some topics......no big deal, have a great evening.
 
Something is fishy. About 15 years ago, Mopar Muscle took a bone stock 340 and added a Comp 268 Xtreme energy cam/springs and lifter kit, 850 CFM carb, Edelbrock Air Gap, 1 5/8" headers and it made 392 HP (a little over 1.1 HP per CI). I followed that same recipe on my motor. There was no fancy head work, no manifold port matching, etc. With the specs listed, the Op's motor (at 422 CID) should have made around 460 HP. A bigger carb should have put it up to over 475. With that combo I see no reason why one HP per CI was not achieved. Like I said, something is fishy.
 
harrisonm said:
Something is fishy. About 15 years ago, Mopar Muscle took a bone stock 340 and added a Comp 268 Xtreme energy cam/springs and lifter kit, 850 CFM carb, Edelbrock Air Gap, 1 5/8" headers and it made 392 HP (a little over 1.1 HP per CI). I followed that same recipe on my motor. There was no fancy head work, no manifold port matching, etc. With the specs listed, the Op's motor (at 422 CID) should have made around 460 HP. A bigger carb should have put it up to over 475. With that combo I see no reason why one HP per CI was not achieved. Like I said, something is fishy.
Click to expand...
Maybe it's your way of trying to find relativity between the 2 engines.......go back to the drawing board and try again.
 
harrisonm said:
Something is fishy. About 15 years ago, Mopar Muscle took a bone stock 340 and added a Comp 268 Xtreme energy cam/springs and lifter kit, 850 CFM carb, Edelbrock Air Gap, 1 5/8" headers and it made 392 HP (a little over 1.1 HP per CI). I followed that same recipe on my motor. There was no fancy head work, no manifold port matching, etc. With the specs listed, the Op's motor (at 422 CID) should have made around 460 HP. A bigger carb should have put it up to over 475. With that combo I see no reason why one HP per CI was not achieved. Like I said, something is fishy.
Click to expand...

magazine builds. Be careful

there was a shop selling motor building here that touted healthy dyno numbers from conservative cams. Seemed too good to be true.

… he’s no longer in business
 
Last edited:
Depac Dyno software/ hardware.
A friend of mine uses that, but he always seems to be having issues with it.
Not saying that's the problem, just an observation.
 
I’ve tested a few real duds over the years.

But the ones that come to mind had some pretty notable deficiencies.

Here’s one......
396bbc. Oval port heads, Comp 280 Magnum cam, ex manifolds, Ede 750, and the big problem...... an SP2P intake.
I don’t remember the tq, but it was low 280’s for hp.
The guy who gave him the recipe for it said it was a solid 400hp combo.
We put some headers on it......35hp improvement.

I ended up getting a small solid cam for it, and an RPM intake.
The Ede carb wasn’t cooperative so I sold him a Speed Demon 650DP.
With the headers it made like 416hp.

Totally different feel with that combo in the car.
The old combo was “done” at about 4500....... and the new combo would easily pull to 6500.
 
Last edited:
136 hp from headers, carb, intake, and a cam change does not seem like too big of a stretch to me on a BBC. Are you of the opinion, @PRH that the engine here could see 100hp with an intake and carb change? I personally don’t see 100hp coming.
 
Interesting dyno numbers.
I am pretty sure what likely isn’t causing you an issue, not as sure what actually is the culprit.
It isn’t the headers , run the same ones on my car, been 10.77 already, hoping to go faster, at more weight than the OP
Likely isn’t the carb either ( assuming it’s operating as it’s supposed to) Holley would be my choice, but years ago I tested a slew of carbs on a 416, several from Pro systems Patrick was nice enough to let me try, and from a 750, 1000cfm 4150, 1025 Race Demon RS 4150, and ultimately an 1100 Dominator, the difference from top to bottom was a bit under a tenth and a half at the track( more like 12 or 13)..that was from Patrick’s 750 to the Dominator( pro systems) and Race demon, which were virtually the same.
Carb certainly isn’t “Killing” this combo.
I doubt the Offy intake is killing it either. I ran a small port Weiand excellerator on my Eddie headed 418 that I just took off, optimal, no, but capable of way more than 100 horsepower above the OP’s dyno pull, and backed up on several combo’s at the track.
The head porting numbers and quality would be a good thing to verify.
Heads I just removed peaked at 270 ish at 550 lift, again, 10.70’s at 3300+
If the OP’s J heads are anywhere close to what he has been told, the motor is capable of making a true 500 horsepower, and potentially running real good in the 1/8 before wheezing badly in the 1/4… Those heads really will make the car a tractor.

To me, the cam is ultra suspect. I won’t run anything smaller than 260@50 on a 4 inch motor. 240 hyd roller is a very bad selection and is killing power. I would bet on it.
I also don’t like leaving compression on the table. Bumping up compression and camshaft would be the two things I would do with this combo before I started swapping bolt on parts on an off

to give you an idea, I had a bone stock 360 shortblock with stock Eddie’s on it that ran 12.23. Not sure what compression, but likely around 9 to 1
Mild porting of heads, and milled them to 61cc, ran 028 gasket on them, ditched the 240ish@ 50 Comp solid cam for the 260@50 Howard’s cam, and took off the missmatched( for this combo) Mopar M1 single plane, and swapped to an air gap.
No other changes, car went from 12.23 to as quick as 11.26 and almost 10 mph( more typically 11.40’s)
I attribute the gain to mainly the cam and compression, the guy did very little( as I found out later) to the heads

1. Cam
2. Compression
3. Are heads truly as nice as you were told/ airgap intake
 
Last edited:
Do you have any more data from your dyno run? What other parameters did they log? AFR, E-temp, MAP?
 
harrisonm said:
Something is fishy. About 15 years ago, Mopar Muscle took a bone stock 340 and added a Comp 268 Xtreme energy cam/springs and lifter kit, 850 CFM carb, Edelbrock Air Gap, 1 5/8" headers and it made 392 HP (a little over 1.1 HP per CI). I followed that same recipe on my motor. There was no fancy head work, no manifold port matching, etc. With the specs listed, the Op's motor (at 422 CID) should have made around 460 HP. A bigger carb should have put it up to over 475. With that combo I see no reason why one HP per CI was not achieved. Like I said, something is fishy.
Click to expand...

And that MM deal is total BS... They can print it, doesn't make it so. That is the one dyno test I'll call BS on every time.

That's a 1hp/CI build roughly. It might make a true 350-355 hp. Been around too many of them and that thing never saw a strip to prove it out. Like many of the dyno engines from MM. MPH always a disappointment.

Definitely something wrong with the numbers from the OP's mill. They changed the distributor and a spacer and it picked up bunch... HMMM One thing I'd guess at is not at WOT, but, that is one of the things you definitely verify prior to making pulls.

I had a 360 with ede's 270 @.500 and a smaller HR cam, victor, 950hp, hooker 1.75 headers and it made 130 more HP than the OP's all the way to 6300.
 
Last edited:
How accurate are the OEM parts he’s using, how about the timing marks on the damper? Port work can cost hp as fast as make it. I ran a name brand manifold from the 80s on the dyno because I had suspected it lost power back in the day and it did, 85hp less than an M1 single plane, this was on on of my 440s, took twenty minutes to change the manifold.
I think it’s like stack tolerance where you get enough things that are just enough off so things don’t fit except here the stack tolerance comes up with with a motor that doesn’t perform as expected.
 
crackedback said:
And that MM deal is total BS... They can print it, doesn't make it so. That is the one dyno test I'll call BS on every time.

That's a 1hp/CI build roughly. It might make a true 350-355 hp. Been around too many of them and that thing never saw a strip to prove it out. Like many of the dyno engines from MM. MPH always a disappointment.

Definitely something wrong with the numbers from the OP's mill. They changed the distributor and a spacer and it picked up bunch... HMMM One thing I'd guess at is not at WOT, but, that is one of the things you definitely verify prior to making pulls.

I had a 360 with ede's 270 @.500 and a smaller HR cam, victor, 950hp, hooker 1.75 headers and it made 130 more HP than the OP's all the way to 6300.
Click to expand...
You may be right about MMs dyno numbers. Bigger numbers may sell more magazines. But it looks like we agree on one thing. The 422 should have made more power. I particularly liked your WOT comment. THAT HAPPENED TO ME. I've had my 69 340 Barracuda for about 35 years now. The first time I built it, I had a one notch over stock cam and headers. When I started to drive it, it felt more like a 318 with a 4 barrel. I don't remember why I thought to look, but the way I had installed the linkage, I only had about 75 or 80% throttle with pedal to the metal. After a quick adjustment, it ran way better.
 
What stands out for me is the tq figures in the original test. Only 42Xft/lb for a 422 Ci engine. Would expect it to be much higher. Dyno problem?
 
B3422w5 said:
To me, the cam is ultra suspect. I won’t run anything smaller than 260@50 on a 4 inch motor. 240 hyd roller is a very bad selection and is killing power. I would bet on it.
I also don’t like leaving compression on the table. Bumping up compression and camshaft would be the two things I would do with this combo before I started swapping bolt on parts on an off
Click to expand...

I definitely think there is more power to be had in the cam. With a 9.5:1 engine I was looking for power out of i'd be looking for a tighter LSA/LCA. And I might see how how it responds to being advanced as well if the valve clearance was there to do so. This effe3ctively would raise your compression ratio by increasing cylinder pressure. I don't think 240@.050 is too small, but more duration would help overcome the head flow restriction. I'd also be running a solid roller. There is no reason not to.
 
Check the correction factor on the dyno. I don't know your elevation or air numbers but that looks pretty weak (uncorrected)
 
TT5.9mag said:
136 hp from headers, carb, intake, and a cam change does not seem like too big of a stretch to me on a BBC. Are you of the opinion, @PRH that the engine here could see 100hp with an intake and carb change? I personally don’t see 100hp coming.
Click to expand...

Not at all.
As I said, that bbc build had what I considered to be a big problem with the combo if you’re trying to make hp......the SP2P intake.

On paper, I really don’t see any red flags with the OP’s combo.
Not any that are of the 75-100hp variety.

If I had it on the dyno here, my “expectation” would be that the numbers would be around 500tq and over 400hp.
“Assuming” the flow numbers are close, and that the overall head prep is decent.

That being said.......”if” the numbers here were a repeat of what he’s seeing now....... it would be an interesting project to figure out exactly what the cork is.
 
Last edited:
OLDSTYLE said:
Check the correction factor on the dyno. I don't know your elevation or air numbers but that looks pretty weak (uncorrected)
Click to expand...

That is a valid concern........ however the bsfc numbers up top are quite poor, and they are derived from uncorrected data.

Though, If the dyno just “reads low”, then the bsfc will look bad as a result.
 
Last edited:
A couple of other random thoughts......

-how sure are we that the CR is actually 9.5:1?

-do we know where the cam is installed?

-I didn’t see it mentioned, but if it hasn’t been done yet, I’d suggest a cranking compression test on a few cyls ....... just to put a cranking pressure number on it.

Oh...... and I’m looking forward to the results from the intake & carb swap.
 
Last edited:
PRH said:
A couple of other random thoughts......

-how sure are we that the CR is actually 9.5:1?

-do we know where the cam is installed?

-I didn’t see it mentioned, but if it hasn’t been done yet, I’d suggest a cranking compression test on a few cyls ....... just to put a cranking pressure number on it.

Oh...... and I’m looking forward to the results from the intake & carb swap.
Click to expand...
Where the cam is installed made a huge difference for me. I installed dot to dot and was off 8*.
 
Kent mosby said:
Where the cam is installed made a huge difference for me. I installed dot to dot and was off 8*.
Click to expand...

Buddy put in a owner supplied Comp Cam multi keyway timing chain set. On the degree wheel it was way off.
 
You must log in or register to reply here.
-

Back
Top