Had my '68 Sport Fury with a 520" Stroker on a chassis dyno yesterday.

[FURYGT]

312 HP at the rear wheels at 4500 RPM and 408 torque at 3950 RPM.

Since the torque converter has a higher than stock stall speed it is not possible to accurately estimate the engine figures.

The engine is a pump gas 10:1 compression ratio stock appearing engine with factory intake and exhaust manifolds as the car is built to race in the stock appearing racing classes.

 

[Rapidtrans777]

Can you say "sleeper". Love it. You gonna dyno the whale?

 

[FURYGT]

Can you say "sleeper". Love it. You gonna dyno the whale?

The builder of the whale told me that the engine dyno showed 550 HP. Some day, I hope to get it on a chassis dyno.

If I ran an open element air cleaner on the Sport Fury I would pick up even more power. If I changed to an Edelbrock Performer Intake I would pick up even more power but for right now it is build to qualify for stock appearing racing series drag racing, which does not allow non-factory air cleaners or aluminum intakes.

Those numbers are for slightly tweaked cast iron intake manifold and slightly tweaked HP exhaust manifolds.

BTW, since the car has a custom built torque converter with some stall speed it is not possible to calculate the engine HP based on the rear wheel numbers.

 

[CBODY67]

Remember that in the 1968 time frame, Chrysler released the Edelbrock aluminum intake manifolds (of that time, similar to the later Performers) that had Chrysler Part numbers cast into them. The 383 and 440 versions were legal in NHRA racing classes, as a result. Part of the Direct Connection program. Some still surface every now and then on eBay. Paint it and few might ever notice. If they do, point out the Chrysler 7-digit part number.

Enjoy!'
CBODY67

 

[furious70]

The camel shaped torque curve is interesting, I would guess the a/f ratio is funky there?
I know y'all like this stock stuff, but that graph is clear evidence of how it hurts performance. Aftermarket carb, intake, and headers and you'd have 100hp more and more torque.
And yes I understand why it's built the way it is and very few of us need to have those constraints because we don't race that class.

 

[FURYGT]

The camel shaped torque curve is interesting, I would guess the a/f ratio is funky there?
I know y'all like this stock stuff, but that graph is clear evidence of how it hurts performance. Aftermarket carb, intake, and headers and you'd have 100hp more and more torque.
And yes I understand why it's built the way it is and very few of us need to have those constraints because we don't race that class.

The carb is an 800 CFM Edelbrock. The speed/race shop that did the dyno testing as well as the person I refer to as my "race car mechanic" explained that the factory cast iron intake is the biggest factor is limiting power followed by the dual snorkel air cleaner (even with a smaller diameter drop down base) is the second biggest restriction in making power. With moving, I may change the class that I race in and therefore may make an intake and air cleaner change.

 

[Mr C]

Love the car and the stock appearing build. What gears are you running out back? Does the class limit the ratios to factory offerings too?

 

[FURYGT]

Love the car and the stock appearing build. What gears are you running out back? Does the class limit the ratios to factory offerings too?

3.73 gear. No restrictions on gear ratios. I went with 3.73 gears because I do street drive the car some. 65 MPH = 3,000 RPM's. 65 can be done for a short time but she's more happy at 55 MPH on the highway but I don't drive it for long distances.

 

[furious70]

What rpm do you go through the traps today? Looks like 4200-4500rpm would be plenty

 

[FURYGT]

What rpm do you go through the traps today? Looks like 4200-4500rpm would be plenty

Around 4500.

 

[furious70]

More gear would be a waste then anyway.

 

[FURYGT]

More gear would be a waste then anyway.

Exactly. The tires are G70 - 15 Bias Ply so they are not very tall.

 

[CBODY67]

In the realm of circle/dirt track racing, there have been classes (for decades) which mandated the use of stock intake and exhaust manifolds. Enter Brezenski! They would "hole saw" the intake manifold runners and "port" them manually. Same with the exhaust manifolds. Then close them up and weld back together. End result, much more total flow . . . in an era well prior to the later "extrude hone" operations (where a somewhat low viscosity fluid is forced through the passages, effectively honing them as it goes through. All without cutting things apart.

Many seem to forget the dimension between the air cleaner housing base plate and the air cleaner top. The beloved Corvette open element air cleaner (the real one, not the more common knock off) has a base plate that is contoured to fit around a Holley 3310 carb. With the 3" tall filter element, but there's probably not more than 1" of space between the base and the top at the carb stud area. Looks great. Performance heritage. But HAS to have the 3" tall filter element. The knock-offs have a base that sits 1" higher at the edges than the OEM Corvette item (I measured it!) with a reasonable facsimile of the OEM coutours to clear the Holley "race bowls" and such.

As I've mentioned previously, using the Chrysler open element air cleaner base (aka '68 Road Runner air cleaner base) and the normal top part of the '66-'68 dual snorkel air cleaner has a stock appearance, just that it has a 2" gap between the filter element and the outer diameter of the air cleaner housing. Works for the normal single snorkel air cleaners of that time, too! All three air cleaners use the same filter element. There was also a snorkless top piece (factory chrome!) too.

So . . . congrats on getting things to the degree of execution that you have.

CBODY67

 

[FURYGT]

Thanks. That is essentially what I did with my air cleaner - I just used the Mancini drop down base instead of the Chrysler base as I needed the small bump out to clear the carb fuel inlet.

 

[67Monaco]

The carb is an 800 CFM Edelbrock. The speed/race shop that did the dyno testing as well as the person I refer to as my "race car mechanic" explained that the factory cast iron intake is the biggest factor is limiting power followed by the dual snorkel air cleaner (even with a smaller diameter drop down base) is the second biggest restriction in making power. With moving, I may change the class that I race in and therefore may make an intake and air cleaner change.

Is the bottom of the air cleaner trimmed/rolled back to the edge of the filter? It's be a way to get an "open" element but retain the stock appearance. I assume yes as you've already got a ton of money in it already but I thought I mention it.

It appears my wife's grandfather did this on the Monaco. I always wondered why, I assume I have my answer now.

 

[FURYGT]

Is the bottom of the air cleaner trimmed/rolled back to the edge of the filter? It's be a way to get an "open" element but retain the stock appearance. I assume yes as you've already got a ton of money in it already but I thought I mention it.

It appears my wife's grandfather did this on the Monaco. I always wondered why, I assume I have my answer now.

Yes, the base that I use is the same diameter as the air filter with a small lip to hold the filter. This results in a 2" opening around the base of the air cleaner to let more air in, although it let's hot air in.

The best air flow for a carb is air that comes straight down into the carb, which is why velocity stacks were so popular in drag racing for a long time. The next best is an air cleaner that is an open element including the top being a filter in addition to the sides and the bigger the filter the more air volume for the carb.