Doing a bit of cross posting if Jay don't mind... dyno data

[Barry_R]

I have not posted any of these for quite a while.

This one just got some coverage by EngineLabs - so I figured I could give it a double up with a little more info here and a link to Jason's write-up for video & more pics.

the engine is built for a Cobra project.  The design intent was to be plenty powerful, but still very smooth & linear so that the car would be still be pleasurable to drive on the street or on a road course.  A secondary concern was the desire for vintage cosmetics - it need to have a strong passing resemblance to something that would have been in a Cobra back in the proverbial day.

It started out as a "normal" 482 build (hard to consider a stroked 427 as normal...), capped off with a pair of "as cast" Survival heads and a Blue Thunder dual plane intake.  Compression is pump gas oriented middle 10s, oil pan is an Aviad.  Distributor is a vintage Accel procured from Faron by the customer.  Carb is a customer supplied custom piece with modern innards and a pair of LeMans bowls.  The cam is a hydraulic roller - specs are 242/248, .643/.637 on 113 LSA

Ended up being a really nice package.  Tuning around the LeMans bowls was interesting to say the least.  They would not tolerate very much fuel pressure before getting overwhelmed.  They also had a rather small 1/8NPT inlet which limited flow into the bowls.  I would get to a point where adding jet would not deliver a corresponding increase in air/fuel mixture.  You could look at the A/F numbers and see where it started out nice & linear, but on the lean side & then add jet & watch them go rich at the bottom and return to the leaner ranges as the bowls dried up at high RPM.  Really does not mean much in the car - how often are you going to experience a 14 second long high gear pull in a Cobra?  But illustrates why they went to the cathedral bowl design.

Engine made really cool torque - look at the curve - 497lbs at 3000 and 503 at 5800 - peak was 559 pounds at 4600.  Horsepower peak was 556 at 5700 RPM, but it had nearly 500 way down at 4700....

Charts, pics, and a link:
Pics will follow as soon as I can get that worthless Photobucket site to work worth a damn.

http://www.enginelabs.com/news/video-survival-motorsports-and-482-cubic-inches-of-fe-fury/

[jayb]

Cross-post away, Barry, I have no objection.  I assume QFT in your chart means a Quick Fuel carb?  It looks like the QFT carb made a significant difference; do you attribute most of that to the fuel delivery issues you saw with the LeMans float bowls on the original carb?

[jimeast]

Barry,

Really nice build.  Seems perfect! 

Several questions;

1) Do you have a video of this engine on the dyno?
2) Would stock adjustable rockers work with this cam?
3) Can you share more info on the carb?

[Qikbbstang]

While your getting hit up for answers. Would you please explain the lowdown on why a motor that's out of it at 5800 is not started earlier its power curve on the dyno?
............Just like to see what that motor does lower on the scale, if it's got 500+TQ at 3K what does that jewel have at 1500?, 2000?, 2500? looks like more fun then a diesel

[Faron]

Also That is a Factory Dist with a Pertronix , Not an Accel , and If I recall its a Pertronix III , was the rev limiter reset , because the factory setting is awful close to your end numbers

[Barry_R]

Factory setting was at 5300 and it did catch me on the first full pull.
The Petronix RPM setting did not agree with my dyno tach and I ended up simply taking it "out" for the remaining pulls

[Barry_R]

I can and have made pulls at 2500 but it feels really "mean" to an engine to park it down there at full load.
Not really much point in doing it since virtually any car will blow past 2500 instantly when you floor it - either against a converter or a clutch.

[NIsaacs]

Can you post the ignition timing, initial and total?

Thanks, Nick

[Barry_R]

Total timing was tried between 34 and 38 - the 37/38 range seems pretty common with these.  I only glanced at the base since it was a Faron modified distributor provided by the customer.  We generally agree on having a lot of initial and a similar end point, with all of it usually "in" by the beginning RPM on my dyno pulls.

The QFT carb was my Engine Masters piece and it was untuned for this engine.  But it was also on the rich side and the engine wanted more fuel through the peaks.  The customer has sourced some higher flowing inlet fittings and should not have any problems "in car" but its interesting to see how just a carb can change things.

In the car this should be a really interesting engine - I bet its very linear and controllable and might be faster around a road course compared to a drag race oriented horsepower build that "comes on the cam" really hard after a slower start.

[900HP]

Beautiful engine Barry, very sanitary