422 dyno fail
- Thread starter Jim Ward
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'68cuda416
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I wouldn't run iron heads unless there was a specific reason for it and if so they would be W2's and a ported set at that, if you have to keep a flat hood then maybe a ported Victor and or an Air Gap but if you will have some kind of scoop or clearance than a Super Victor.....again ported would be much better obviously, I run big carbs on everything I ever have owned but they all are some form of rowdy so as of yet no issues going that route and on my 415" street strip deal I ran a 970 Bigs prepped 4150 that worked quite good, the compression is low but maybe you said you did that because of the iron heads.......but again if you could run an aluminum head and with the right cam pick I think 11 maybe crowding 11.5-1 would be possible with a good tune on pump premium, then at minimum a set of step headers and depending how rowdy you got things maybe a set of 1 7/8's, also in my opinion a converter built off of a dyno sheet from a reputable company will net the biggest gain and or loss if not done correctly too in overall vehicle performance. That would be a start for me if I was doing a larger cubic inch stroker and it sounds like you want and or except some decent power from the package........525 hp should be ridiculously easy and 550-575 type range can be done with minimal effort all things considered.
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'68cuda416
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Also it would be solid roller for me every time on any of my builds since so far they have all been fairly rowdy to a lot of rowdy......not even gonna consider anything else
Scody21
Just send it
That’s Funky.
For reference My current 340 is .30 over, with cleanup job of 2.02 J heads, at 10.2/1 with comp cams XE285HL in at 109 with 241/247 at .050, Holley 750 DP on top of a stock Eddy airgap and TTI headers. On the dyno after brake-in with over night cool down, and then warm up and 30 minute heat soak made 391 HP and 385 TQ on 91 pump gas. This was done on a known dyno in Portland that runs true to others in the Portland metro..
For reference My current 340 is .30 over, with cleanup job of 2.02 J heads, at 10.2/1 with comp cams XE285HL in at 109 with 241/247 at .050, Holley 750 DP on top of a stock Eddy airgap and TTI headers. On the dyno after brake-in with over night cool down, and then warm up and 30 minute heat soak made 391 HP and 385 TQ on 91 pump gas. This was done on a known dyno in Portland that runs true to others in the Portland metro..
'68cuda416
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You had more compression, better carb, better intake, better headers.......it all adds up
autoxcuda
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'68cuda416
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What headers are they? Did he say? You may be right and I was just going off of everything that he listed in his post that sucked.
Scody21
Just send it
What dyno is being used? From the red stand in the photo it’s not a SuperFlow..
K.O. SWINGER
Meeting in the alley since 1976
In my opinion even with the iron heads you should be looking at a static compression of around 160, also at that Edelbrock 750 is sporting the stock jets that is about a 360 horsepower setup max IMO.
'68cuda416
Well-Known Member
I have had friends with Chevy's and Fords that ran those spec converters, 3800 and similiar plus or minus........and they all had 4.10's as me, similiar power and or a touch more at least off their dyno sheets but I had a custom 8" 52-5400 range one done and I ran high 6.60's and low 6.70' and they were all low to mid 7's in the 1/8th.........piss poor useless converter pick is what i'm hanging my hat on.
There's more in that with an intake and carb change. Seems to me the single plane intake (and small one at that) with the small carb is really a bit of a mismatch for your bigger inch motor and decent cam. Others on here have built more SB Mopars than me but based on my sample of one 408 build, I think you can tweak a few things and wake it up. Yes, CR is the easiest way to make torque and power so you will live with that. And with iron heads, and if you want to run pump fuel, perhaps you cannot go much higher. My 408 with mild ported Eddie's, a Super Victor with an 850 DP, SFT 251/[email protected] with .560-ish lift, and 10.5 CR crossed 500 #-ft at 3500 rpm. Was the dyno lying? Dunno...but with 1-3/4 Hooker Super Comps and a 5000 actual stall ATI 8" TC in the car, it has run a 1.51 60', 7.11 eighth mile (quarter mile time is compromised as it's geared wrong - 4.56 axle). Car weight is unknown but likely in the 3300# range.
I share just to compare/contrast why I think the intake and carb are limiting you. If my 408 can do this, your 422 can come closer given the 9.2 CR with the right intake/carb. As for the heads, peak flow is not everything. Area under the curve is what makes power as does sufficient bowl volume to draw from. If it was mine, I'd start with an intake and carb change and go from there.
I share just to compare/contrast why I think the intake and carb are limiting you. If my 408 can do this, your 422 can come closer given the 9.2 CR with the right intake/carb. As for the heads, peak flow is not everything. Area under the curve is what makes power as does sufficient bowl volume to draw from. If it was mine, I'd start with an intake and carb change and go from there.
It's not the cam...
Intake and carb are the issue IMO. Heads would be next on the hit list.
Intake and carb are the issue IMO. Heads would be next on the hit list.
Well iron heads when ported right can move out.
As stated many times already I'd ditch the intake and carb first.
With that said I have an old port o sonic intake my super stock racer neighbor gave me.
He said it was 2 tenths faster then an ld 340.
But it is far from stock the ports are raised amongst other things.
As stated many times already I'd ditch the intake and carb first.
With that said I have an old port o sonic intake my super stock racer neighbor gave me.
He said it was 2 tenths faster then an ld 340.
But it is far from stock the ports are raised amongst other things.
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Those are the three items causing the issue.
The cam is nice. I don’t have an issue with it. The cam is telling the heads to breath and they can’t, coupled by the intake which can’t breath deep enough. The carb is a-bit small for the cubic inches.
Did you come up with this combo or is it the machine shop combo? With that torque and low hp, your not flowing enough air for high rpms for the hp to develop. Choking point? Intake then carb and then heads.
I'm no builder but seeing how stock 340 is 325hp, I would question the quality of the builder?
rustycowll69
Well-Known Member
My only question is, how much time was spent on the dyno? I mean did they just plumb it up and run a couple pulls 'out of the box'? Or did they do some actual tuning in between pulls and improve the performance?
It's choked.
Not the carb at all. A stock 440 Magnum made 375 hp with a veeeery mild cam, & a dual plane intake & a 750 cfm carb of similar design.
Carb is more than big enough with a single plane intake.
Did the dyno operator check the carb to see:
- if it was getting WOT
- if the secs were opening
- if that carb has a choke linkage, it can stop the secs from opening if misadjusted
Carb is more than big enough with a single plane intake.
Did the dyno operator check the carb to see:
- if it was getting WOT
- if the secs were opening
- if that carb has a choke linkage, it can stop the secs from opening if misadjusted
Cal Tonsley
Well-Known Member
I’m curious to know what the total timing was?
To answer a few questions that have been asked. Timing is set at 36 all in. The headers are Doug’s D453 1 5/8”. The carb is one that the shop has. I am taking a 850 Holley today to try it. I will also be buying an Air Gap intake. The premise of this build was to try to make as much HP as I could while still maintaining as much of the factory look as I could. I sourced as many parts as I could from members on this site while trying to research whether they would work with what my goals were. Obviously this combo is no good and I will post the results of the changes that will be made in the next few days. I appreciate all of the knowledge and advice from all of the members that have chimed in to help.
SixPaksRule
Well-Known Member
Why so much camshaft? Over cammed motor
Stroker motors for the street do not need that huge cam to make big power. You should be running a six pak for induction.
Start with specs for a racer brown hyd cam, this cam hauls the freight in a 10:1 stroker 6 pak.
ssh-25/44
286/292 485/510 108cl
Stroker motors for the street do not need that huge cam to make big power. You should be running a six pak for induction.
Start with specs for a racer brown hyd cam, this cam hauls the freight in a 10:1 stroker 6 pak.
ssh-25/44
286/292 485/510 108cl
roccodart440
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Maybe they flow well for an iron head, but [email protected] on a 422ci engine isn't very impressive at all. Sorry to tell you this but staying with iron and putting a bunch of cash into them was a mistake.
The cam looks fine.
I'm not familiar with that intake. The only intakes I run are eddy perf RPM and victors.
I think it would respond to more carb.
Also, try an HVH super sucker 1" spacer. They usually add 10-15hp and tq on a dyno.
Last, a dyno is a break in tool and a test and tuning tool. Don't get wrapped up in the numbers. I've had my car on two chassis dynos and one was humbling and the other was flattering. Guess what, same combo on both, same ET at the strip.
roccodart440
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Timing looks good. Those headers are small for a 422ci. It will probably like the 850. The air gap IMO is the best dual plane.
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