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My experience so far has been two emails sent, two replies. I have rung once and spoken to Russ Arao.
He says he is willing to send a head here (Australia) for me to have a look at. I pay for shipping. He also promised to send me some better pictures of the heads, valvetrain etc so I guess that'll be a case of wait and see.
Apart from that I can find no direct comment from anybody that's tried them and very little comment from anywhere else except a hot rod magazine from the US that is quoted on
Evolutionary products for pushrod engines.
Tim.
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Dear Tim,
Although no comparative data was posted, Arao Engineering posted dyno results at
http://www.araoengineering.com/dnochrts/dyno_sheets.htm
The 360 SBC (4.06 x 3.48), using a Performer RPM intake and a 750 Holley had a virtually flat torque curve throughout the plotted data -- from 524 lbs-ft at 3000 rpm, peaking at 553 lbs-ft (at 5000 rpm) and easing to 524 lbs-ft at 6000. Torque dropped to 467 lbs-ft at 7500 rpm -- which is way faster than you want to spin an engine using factory rods and crank, etc. The camshaft was fitted with hydraulic roller tappets, but the lift (presumably at the valve) was only 0.479/0.518 (int/ex) and the claimed duration (possibly at 0.050" valve lift "checking height") was only 226 degrees. Since the compression ratio was not reported, no meaningful direct comparison/contrast can be performed; however, that's a lot of power from such a small camshaft.
We don't know the LC/LS, advance/retard of the cam, etc., etc. All those things are important, but those lift and duration figures are easily streetable even in a roller engine. The use of hydraulic (rather than solid) roller tappets reinforces this perception.
The website refers to the aforementioned engine as "seen below" in a "1968 Chevrolet Camaro SS-396" -- but the engine shown is supercharged and injected. /ubbthreads/images/graemlins/confused.gif
The picture of the engine associated with the pickup truck looks like it has Holley's "Keith Dorton Signature Series" (or "Track Dominator" or other similar) intake topped by a "Dominator" style carburetor. Holley's #0-80186-1 is a 750-cfm Dominator carb.
One critical consideration in the dynamometer test results is a component known as BSFC (Brake Specific Fuel Consumption). In SAE units, this is the pounds of fuel per horsepower per hour. A
really good printout will show you BSAC (Brake Specific Air Consumption) and the air:fuel ratio as these change across the test.
I was hoping for the same from Coates International, LTD. regarding their CSRV heads, but they are apparently doing industrial engines first. They had a streetable 351W that supposedly made 967 bhp, naturally aspirated on pump gasoline! Granted, "streetable" is a VERY subjective term, but it's almost a thousand horsies without a blower! WOOHOO!
No, the innards of the 351-W/CSRV were not stock. And yes, they did a modified 5.0 Ford (aka "302") that produced similarly insane power.
Email me at
[email protected] if you find any of this helpful and wish to discuss it further.
Best wishes!
Jesse (wireflight)