73 Dodge Charger 400 big block dyno

[Michaelgt450]

750 Edelbrock Performer Series Carburetor 1411
Edelbrock RPM intake manifold 7186
Edelbrock RPM cam 7194
TTI headers 1-3/4
Two and a half inch exhaust with Dynomax super turbo mufflers
High top pistons 11 to 1 compression don't know the actual compression
323 rear end gears
MSD ignition coil
Auto lights 85 spark plugs
Stock cylinder head [not ported]
Timeing at 36
Axcel 9000 ceramic spark plugs wires
Torque converter TCI stall 2400
180 thermostat
Power steering AC installed but not working
Stock crank stock fan clutch stock 727 with a shifter Improvement kit
If you have any idea on how to improve hp or torque let me know

[70 sublime]

Better cylinder heads ?

[cdr]

get rid of the Super Turbo mufflers & get some that are the straight through design,, dyno max Ultra Flows  or the Magna flow will help,,, total timing 38 to 40 ish it is all trial & error ,  it all depends on what you expect driving it,

[kent]

No porting to the stock heads. Certainly looks like the weak spot.  

[Michaelgt450]

Thank you for the recommendation what would you recommend what brand of cylinder heads Edelbrock?
Are the MagnaFlow loud at idle I kind of want to keep it quiet... what a carburetor spacer make some power or 160 thermostat...

[cdr]

I have magna flows, they are a little bit loud, but I like them

[Michaelgt450]

I will definitely look into MagnaFlow mufflers hopefully they're not too loud and don't make up a little bit more power anything else besides mufflers and cylinder heads??

[kent]

I should have asked you first Michael.
Are you not happy with it? You will certainly spin them with that.  Do you need any more?  Or do you WANT more??

[Michaelgt450]

I am kind of disappointed in the results I was hoping to be at least at 400 at the wheels or 350 kind of want to get it there... don't get me wrong it can spin the tires but was hoping for a little more

[kent]

Always nice to have more.
Any chance Michael of getting a few pictures of your car? I checked out a few of your other pictures but never seen the car. I have a soft spot for those 3rd generation Chargers. I had one as a kid. Would love to get another but I'm pretty sure that boat has sailed.

[Michaelgt450]

Sure.. the charger with my dad a year ago he got diagnosed with pancreatic cancer 4 year me and my dad would work on it when he would be done with his chemo and radiation treatment we would work on it day and night and on Father's Day I revealed it to him to turn it on... on October 21st my dad died.. he always wanted to have 400hp

[kent]

Sorry for your loss Michael.
Glad to hear he got a chance to try it out. I know that would be great memories for sure! Well on that account you better get at it. You will have no problem reaching your goal with a little more tuning/cash. I also think the exhaust could use a little more thought.

Great looking car Michael! Thanks for posting. Never be shy of posting more of that beauty on here.

Once more my man sorry for your lose.

[Michaelgt450]

Thank you it sure is a lot of memories I'm also glad he did get to try it out right now I'm putting mirrors on this car only came with one mirror what the heck I also need to put a brake vacuum or something like that because this cam doesn't have enough vacuum for the brake booster it also needs a new steering box.. like what on the exhaust??

[kent]

Sorry Michael. I thought I read 1 7/8 exhaust. 2.5" should do nicely.

Looks like the heads. Originals eh? Wow you think with all those go parts she would have kicked it over the 400 thresh hold. 27 more ponies to go. Would tuning do it? Different jets? Timing? Man your close. Ever see Nicks Garage on you tube? Give him a call. He's pretty good at that stuff and don't mind talking. Like I say your real close.

[Michaelgt450]

Damn I just re-read what I put it's supposed to say 1 3/4 for the headers not 1 7/8 me and my dad used to watch Nick's Garage on YouTube I also forgot to mention that this dyno Run was also from dyno tuning it the air-fuel ratio is perfect.. says the guy that tuned it also the cylinder heads are the original casting number is 346

[BSB67]

Sorry about your dad.  I lost my dad and my father-in-law to pancreatic cancer.  Bad stuff.

That motor as built will not make 400 RWHP even on a JynoJet.  Probably 300, and maybe 325 with everything right as rain.

Cylinder heads are where power can be made, but also can be a power suck if the head work was marginal, which often times is the case.  Also, the motor with that cam should pull to at least 6000 rpm, probably 6500.  The dyno run stops at 5000.  Why?  Were the valve springs or other valve train issues causing the lack of rpm?

All that said, the first thing you need to do is a cranking cylinder pressure test and report back.  I'm not aware of any decent pistons for a 400.  Low cylinder pressure, marginal heads, and that size cam can really conspire against the short stroke 400cuin making good power.

[Michaelgt450]

Sorry about your dad.  I lost my dad and my father-in-law to pancreatic cancer.  Bad stuff.

That motor as built will not make 400 RWHP even on a JynoJet.  Probably 300, and maybe 325 with everything right as rain.

Cylinder heads are where power can be made, but also can be a power suck if the head work was marginal, which often times is the case.  Also, the motor with that cam should pull to at least 6000 rpm, probably 6500.  The dyno run stops at 5000.  Why?  Were the valve springs or other valve train issues causing the lack of rpm?

All that said, the first thing you need to do is a cranking cylinder pressure test and report back.  I'm not aware of any decent pistons for a 400.  Low cylinder pressure, marginal heads, and that size cam can really conspire against the short stroke 400cuin making good power.

Thank you and thank you for replying. So sorry to hear that my condolences to you. the guy that was doing the tuning said he stopped there because it was at 110 miles an hour and he was looking at my tires he doesn't know if they're rated it for that high miles... which is why he kind of told me that it had a little bit more power. Also I will do that I really need to check the compression on this car
If I can't get 400 out of this car at the rear Wheels at least will it be able to run low 13th or high 12

[Nacho-RT74]

https://www.forbbodiesonly.com/moparforum/threads/the-slug-400-on-the-dyno.80843/

[Nacho-RT74]

All that said, the first thing you need to do is a cranking cylinder pressure test and report back.  I'm not aware of any decent pistons for a 400.  Low cylinder pressure, marginal heads, and that size cam can really conspire against the short stroke 400cuin making good power.

Keith Black KB240 on a blue printed block can be set at 0.020 below the deck. Way better than stocks which sits around 0.100-0.120 below the deck... or so. Acomplish those pistons with 0.020 gaskets and will be on nice numbers I think.

I think Racedodge member here made over 400 hp coming out from his 400 engine on a truck using those pistons. Along with one of the summit cams, can't recall which one. He posted bout that build loooooong time ago.

But the key is on the pistons. Is where the power was reduced on the 70-72 period. Closed chamber heads will help too of course and maybe at this moment the easier to change, but since 67/68 Chrysler was already using open chamber heads and still getting the power. Pistons are still the key.

[kent]

Wow what a great read. I know this wont happen over night, but really interested where this will go.
Would a fresh set of 906s do it along with thin head gaskets??
BSB67 ,Nacho so you think the wrong pistons in this set up??

[Nacho-RT74]

I know the OP it says 11:1 pistons, but I never have heard on these last 20 years about pistons availability with that CR for 400s. Maybe old school pistons made on 70s throught 90s ? Dunno.

11:1 pistons are a higher CR than any stock 440 around ( which were advertised as 10:1 ). If that was true I think a 400 with those pistons should be close or a bit over than a 440HP with stock magnum camshaft, intake and carb. Honestly I don't think they really exist. Not at least from the last 20 years production. Only HiPo pistons available from the shelf for stock stroke are the KB240 which are rated at around 9.5:1 or close to 10 CR on a blueprinted build. I know Diamond or Ross make pistons for 400 bore but for strokers engines as far I know, not stock stroke.

Need to note I'm not an engine builder or a performance knowledgement guy like BSB67 is ( and many others ), but just by what I have read and learnt in theory

[BSB67]

If I can't get 400 out of this car at the rear Wheels at least will it be able to run low 13th or high 12

Anything is possible, it is simply a matter of how much you want to spend., and how you want to reach your goal.

As an example:  Lets say the goal is an et of 12.99.  One way might be to to get there with suspension mods with the power you have now. With a 4.30 gear, 4000 rpm converter, and slicks, you might be close.  Another way might be to add power by putting on ported 915 heads, or 75cc Eddy heads.

I personnally prefer making more power.  If 12.99 is the goal, 325 RWHP should be enough with your current stock suspension/tires/gearing.  Assuming everything else is right with the build and tune-up you have now, cylinder heads, and maybe a cam swap should get you there.

Car weight and elevation will play a meaningful role in how the car et's as well.

If you really want 400 RWHP and keep decent street manners, you should consider a stroker crank.

[BSB67]

BSB67 ,Nacho so you think the wrong pistons in this set up??

I have no opinion on the pistons.  For me it is unimportant at this point considering the motor is already done.  It is what it is.  I would say that it either has an okay piston as Nacho suggested (KB240), or something worse, as there are no good piston options available.  My opinion is that if the compression is low (likely), either it needs to get cylinder pressure back with cylinder heads or pistons.  Heads is easier, but may, or may not be enough.  But if you are going to pull the motor and rebuild it with new pistons, it would be silly to not put in a stroker crank.  Said differently, I don't see putting in a different 400 cu in piston as reasonable choice at this point.

If a guy is starting from scratch and wants a 400 cubic inch motor with good cylinder pressure, he needs to have a very clear plan to get there, and the smallest details matter.

[Nacho-RT74]

Or as many years we talked about, use low compression 440 stock cast pistons into the 400, but I'm toward an specific piston build for the purpouse/engine target, so won't be dealing with small bore differences, tolerances and skirt lengths.

I was to spice up my 400 with those KB240s and already had the pistons in hands ( actually the pistons are still with me ), but while searching for forged 383 crank to replace the 400 cast crank not because needed but prefference, accidentally got in hands for cheap a 440 forged crank ( seller thought it was 383 crank )... then the devil got inside me and went for the stroker LOL... basic one on 3.75" stroke with the 440 piece I got. But if wasn't because that, I was build the 400 with the KB240s and I'm sure was to be plenty happy.

[Michaelgt450]

So it looks like I definitely need to check the compression rate as soon as I can I will check it