street/strip 511" build with dyno results

Howdy,

I was asked to share my 511 low deck build that will live in our "68 Dart GTS. The engine was built within the following parameters:

-Must fit under stock hood with n20 plate and 4" filter

-Can run on pump 91 in a pinch (I am a Sunoco 110 guy)

-Stock appearing long block i.e. aside from headers, intake and carb it resembles an original 383 magnum

-250hp nitrous friendly

-target hp/tq 625/625, 6500 max engine speed (shift 6200ish, cross stripe 6100ish)

The car is 3550 lb on the starting line with driver etc. I am moving up to a 28x11.50 ET Bias DOT and also have a set of 28x9st (stiff wall) to try.

Howdy , I see no dyno sheet

The parts list:

400 block, aluminum caps/studs
4.250x2.625x2.200 PEP crank
RPM rods, 6.535/2.200/.990 with ARP 2000s
4.375 bore w/ 12.5cc reverse dome pistons, 1.32CH 1/16×1/16×3/16 hellfire rings

440 source heads decked to get 80cc chambers
REV valves, new guides, two new seats amd a light bowl cleanup.
Comp 1.5 ratio steel rockers
Tensilemax retainers with CM locks
Isky 9915 springs at 1.930ish IH
3/8 push rods
Stock 68 383 valve covers

Bullet solid roller spec'd by Hardcore B
-.650 lift, 275/280 109 street roller


Holley SD intake with the floor dams removed

4150 1000cfm Thumper carb

1-7/8×3" headers

That should be a very fun street car !!!!!

Dyno sheet:

An in progress shot

Very nice build and results! Similar build to the 505” in my ‘73 charger.
Any port work done to those stealths? Were they cnc stealths or standard? Those Comp Magnum rockers have been serving me very very well for 3 years now with track time and lots of street miles.

Good luck at the races…..should run real hard.

The heads were not ported. There has been speculation that a bigger intake and backing up the cam a few deg would net substantial gains.

Thank you for the feedback kn the rockers. I thought they were an exceptional value.

Still rocking the all aluminum crash box:

Nice, how much compression?

11:1 CR

I usually run a 50/50 mix of pump 91 and 110 on the street. 112 or 116 on the kit depending on the jets.

Ty!

Nice! I was surprised how low in RPM the power peaked but, it's a small head and intake ...AND header. Impressive to me for sure. I think this is an interesting comparison between the 512" AndyF posted with bigger heads and intake but smaller cam.

That's super inconspicuous, I dig it! Really impressive power from unported Stealths!

Looks fun!

Anyone else notice the "L2" AFR bank is consistently leaner than the "L1"?

275/280@.050?

274/283@.050 to be exact sir.

There was an exhaust leak developing on the last two pulls.

For the morning crew

IMO, That is a lot of duration for only 11.0 CR

Impressive build for sure, especially when you factor in the unported stealths, which are the current cork in the system.

The Holley SD never disapoints, best low profile manifold for the BBM ever made.

I would think that cam has too much duration also, but it seems like a great match for the rest of the combo.

Iplease keep the following in mind - ts a small tire stick car that races om limited or no prep. Not a bracket car that hooks a 14x32 in the car wash lol. I'm more into all out racing cmpetition than the stop light to stop light fonzi car show thing too. 1/8th or 1/4 mile from a dig.

The plan is a bigger intake/glass hood and some CNC work on the heads. I don't want the engine making 500 ft lb of tq at 2500 because it makes the car undrivable on the street. Those of us that have big hp cars woth a limited tire and a stick know what I am getting at here.

As it sits we will make 800+ on nitrous.

To all of the " i would have done it different " cfolks...what would you do and why? Keep in mind that this is a small tire, limited prep street strip car with a stick.

I would not be surprised if you find another 40 hp with a bigger manifold and well-ported heads.

Finding a low deck single plane took a while! Glass 6 pack hood on the way!

I used to port the crap out of Street Dominator manifolds, oout of the box they flow about 270 if I remember what 440Jim posted but ported they will go 310 plus. My ports usually wind up 1/2 way between 906 and max wedge size but since you have standard port windows prolly wont pick up that much.

I agree that the cam is a good choice for a no prep stick car, pretty narrow torque/HP curve which is perfect for a light stick car

The heck with more motor work. I'd be saving up for a trans
Doug

Me thinks he has several different choices to use in his shop, HUH Jeremiah: whistling:

I wanna drive it !

You make an excellent point there. The transmission and clutch are maxed out with this engine on a power adder. A g force 101a will replace the a833 at some point.

My original plan was a smaller porter racing heads street roller cam and stealth head upgrade to the 451. That block is headed to get a sleeve and some good rods this winter. It will be interesting to see how much n/a power can be made with the stock manifolds.

My combo is similar but with better heads but less cam. 272.279 solid roller, Stage 6 heads, 850 Quickfuel carb, 12.1 CR on Av Gas since its the same price as normal fuel down here, I get 645 rwhp & gets my factory trim e body @ 3720lbs running 10.5@125mph. I could probably run faster with a bigger carb but I built this to race in our 11 zero class on the Friday night drags. When its colder & no track prep, 10.80s are the norm, just have to sandbag at the finish line.

645 wheel hp is no joke. I would be very happy with 650whp on the wheel dyno on a small n20 kit. My previous best with the 451" was 572whp on a 175 shot. Thinking I can run either a lean 125hp tune up or 150hp jets pulling some timing to reach my goal.

Naturally all of that hp gets skewed off the chart when the clutch tamer, n20 progressive and erratic track conditions come into play. Add in the flashlight start and it's anyone's guess if we are leaving off of the progressive's time delay or not lol.

Junk. It didn't meet your torque goal. Just kidding!!! That's a really cool combo and I'm surprised at the power w/ unported Stealth heads!
That car should really make some people scratch their heads after it makes a pass! I love these type of bada$$, but unsuspecting builds.

To those questioning the size of the cam...remember, it's a nitrous motor. That changes things. I've seen some crazy big cam specs for motors that if weren't being sprayed hard, you'd think were WAYY overcammed.

All of my custom n20 cams have longer exhaust duration.

This thing also needs moderate RPM to do it's thing. I can't leave off idle or anywhere down low like an automatic; I need RPM to slip the clutch and keep the nitrous kit from sending the carbutetor to heaven. With a 4.10 gear and a 28" tire my usable down track rpm operating window is 4400-6150. At 4400 RPM we are making within 20 ft-lb of peak tq and 500hp and by 5100 RPM we have picked up 100 hp and it carries until redline. Lastly, the engine makes just short of 600 ft lbs at 3900 so I am not really sure why we are calling it a narrow power band. Maybe someone has a dyno sheet from a similar build as an example? I have had a few people indicate the engine is down on power yet no one will tell me why lol.

Maybe a couple : D

That said the face plated a833 has served me well. I ordered a spare set of gears and a cluster and have not had cause to use them. Slipping the clutch is the only thing keeping it alive. I also adjust the RPM window switch to turn off the nitrous below 4500 and above 6100 which really helps on the 2-3 and 3-4 shift.

If any of you automatic guys want to know what it feels like to shift out of 3rd gear let me know : D. Just having fun no disrespect intended.

Thank you Nick it has been a humorous and entertaining journey. There are so many facets to gettijg a csr like this to work half way right sometimes I am like a blind man trying to open a can of beans with a swiss army knife.

I am looking forward to seeing where your fury upgrade goes. These street cars can be pretty darn fun with a little nitrous don't you think?

Do you know what the flow nu,bers for a CNC ported stealth look like? Who has the best program?

Wheres the cage?
Doug

Down on power ??? I think not, for the cyl head you are makin some STEAM, cant wait for the track results !!!!!

Unless you wanted to run totally N/A I don't feel like there's bang for the buck having them cnc'd. I'd think there is that same '40HP' or so just doing a few hours of MW opening to the intake runners and then using a MW intake which would carry power further. It's a strong build for unported stealth heads! Them being small and that you were using low compression for pump, AND in consideration of the valvetrain; I may have missed on the cam by 5HP and for that I'm so sorry . I'd have thought it would have power peaked about 200 higher but not exactly sure where the ICL is at currently. I'd bet moving it would shift peak for sure. I don't recall if you mentioned how much spark adv made the best power? For whatever reason, your builds go relatively unnoticed (and maybe that is your goal) but they are impressive relative to the parts you're using. Again overall GOOD JOB!

I haven't read everybody's responses, so this may have been mentioned already...

It's only a "narrow" power curve if all you do is compare the HP peak RPM with the torque peak RPM. If you look at where the torque is > 550 lb-ft, the answer is "almost everywhere".

I think the HP NA is maxed w/ the unported heads; if you port the heads, the next restriction is that intake. If you always spray it to your horsepower goal, I don't see the point in changing what you have now.

Does that car have to pass tech to race where you do? I don't see much there that says you do...

Nice build. Those heads seem to be decent heads. A friend of mine had them out of the box on a mild 440 with small roller and 6 pack set up and in a 4000# 71 road runner and went 11.50's. As for the cam being too big, I don't think so. I have seen this before, small heads large cam just seem to work good together. Dom@Thumpercarbs has something similar with large cam and small head. A 470 with RPM's and a 276@50 on the cam. This is in his 72 dart and goes 9.70's N/A. I have read somewhere that large cams compliment small ports. This is looking to be true.

That's a fantastic quote!!!

It's super cool, there isn't anything more exciting than a quick manual trans Mopar. It should really, really fly on the hose!

My car is overcammed for n/a work, but it worked great on the nitrous. It picked up 1.2-ish seconds on only a 73 jet, the added duration really helps. It's addicting for sure, doing caltracs/monos/vikings on all 4 corners this winter, and am going to possibly upgrade the fuel system so I can feel safe spraying 225+... at least from a tune standpoint, not from a stock LY rods and six pack pistons standpoint, lol

Last numbers I was given from a set were 346 at 7, 348 at 8. Exhaust were 229 at 7, 232 at 8.

2.14/1.81.

4.38 bore

I ran out of tape for the seats but the lap belt clicks in really good (Doug makes good points as always).

Thank you for the support. I figured on struggling to find 600hp with the unported heads. I have one more set of Stealths to mess with so we will have to make plan for those. What didn't we like on the valvetrain? I sure wish the crane steel rockers came with more ratio options.

It has a battery hold down, two throttle springs and I tossed the Yosemite Sam floor mats when we got the car.

Are they supposed to be checking for something else?

Thanks for sharing your thoughts on the hp/tq. Good food for thought!

Whoa! I had no idea. My understanding was 320@.700. Thank you for sharing that info.

The LY rods in my GTS looked mint other than #4 which bent due to the cylinder splitting and filling with a coolant. Bearings looked perfect on all mains and rod bearings. I was really surprised by that. Looking forward to seeing how much you pick up with a suspension upgrade on the Fury!

Safety belts
Scatter shield (4-speed)
Roll bar or cage (bar >= 10.00; cage <10.00)
Driveshaft loop
Driver's jacket
... and the list gets longer as the car gets faster

Or are you running at an "outlaw" track that doesn't really bother w/ tech inspection per the NHRA/IHRA rules?

They only claimed around 320-ish, so I have no idea where 340++ #s would come from...

The last CNC Stealths I saw tested (Dwayne posted something about them in the last year or so) didn't even get to 320; MCH isn't doing the work any longer, so the additional blending & CNC chamber work that goes along with the basic CNC work to the ports alone isn't being done any more, IIRC.

Safety bellhousing, billet flywheel....check
Driveshaft loop....check


I will have to double check on the rest of that list lol

Yeah i dont think you'll see 340+ cfm out of a 2.14 Stealth that is remotely affordable. Call the numbers however you want but ported you'd do REALLY well to get over 700 on a decent motor build similar to this.

The valvetrain is good and matched for what your doing but there is better like HS and TD paired etc. but again that all goes into consideration in the whole scheme.

What are the performance targets for the car?

On spray and N/A?

N/A - snappin necks
On spray - cashin checks!

340+ cfm stealth heads?

Just when I thought I'd seen everything

Thanls to Woody B for setting me up with this M1

The SD

Has anyone ever seen a set of functioning "super stealths" ?


I recollect them having flow numbers reported in the 340 range. The intake port wall looked very thin on one side from the pics in 440sources ad.

They have 440 size ports, but the pinch is moved over so .650 offset intake rockers must be used, I ported mine & are Max wedge size, Mine flow in the 340's , had them on my junk for many years

Very cool! I want a set! I dont think they still sell the super version?

These were done by MCH - All I know is what I saw on the flow test sheet. Don’t know if they require special rockers or not.

Nice build but I have been racing a long time seen lots of stuff. Just because you race on the street or an outlaw track, don't skip the safety stuff. One thing about trying to put that much HP on the street is you are usually very close to spinning the tires at a lot of MPH. Bad things can happen. And TV show or not those street racers have had a lot of wrecks the past few years both on and off the track, couple got killed. So be safe. And if done correctly a good roll cage will stiffen the car and make it go faster, done that myself several times.

I've heard RPM and heavy bobweight kills the LY rods. I don't think I'm making enough power to hurt them but I also don't think they are safe long term much above 6000 rpm.



That is such a grudge racer answer.

Impressive numbers, must be one of the reasons why Charlie’s
Car runs so good. I should probably crawl out from under my rock more often.

Agreed!

Gentlemen....11.50 tops! Looking for 88mph in the 1/8th

Oh man...I dont even have any tattoos. One of my biggest pet peeves is the outlaw gangster racer thing. More like working 80 hours a week supporting a family and your car hobby. Flat bill hat and a hoodie doesn"t mean ****

You make several good points here. I will take them into consideration as we move forward (that is my serious answer).

Never measured an M1 nor an SD intake but, at a glance there won't be a big difference (maybe 10-15 tops) I just don't see a big increase in mcs and the runner is still limited to Std. port height. Based on the images, when Wilson modded AndyF's M1 they welded externally on the runners etc. That intake was surprisingly good but then the MW intakes with less runner turn where a gain again over that. Just speaking from a bang per buck perspective. That being a low-deck...I KNOW OF a 'prototype' manifold that would be interesting for dyno comparisons assuming your heads were opened to MW

Thank you for the feedback. I intend to measure the volume of each intake.

I probably won't though : D

Would measuring height and runner CSA be valuable data?

Is this bad time to talk about a hood swap?

Also stumbled upon some TTI step headers. Sorry red Charger! I already feel guilty lol.

You better paint that hood a ratty faded blue! Cool car, great build. Hope you have a ton of fun with it.

I have three or four colors of flat blue in my trim paint cabinet. You read my mind on that aspect.


Part of me wants to paint it organisol. Any thoughts on that?

I am looking around for an old s&w roll bar kit as a winter upgrade too.

Before I move forward I need to either harvest the TTI's from my Charger or pry open my (very flat) wallet and get a set on order.

Winter upgrade list:

Hood swap
Intake swap
Possibly a cam timing change
Upgrade safety equipment
Strange S60/cal tracs/28x11.50 DOT bias M/T's


After this combo gets wrung out I'll retire the car for a resto project and focus on my good cars.

roll cage needed when car gets "upside down". [i couldn't help it............. ]

Easier to weld up the exhaust that way. I wish they would fix that issue...which is about 5 years old lol.

many years ago, around here we all said : "it's impolite to show God your mufflers......."