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Saturday, March 5, 2011

383 Chev

This was a build that was recently completed and dyno tested. Actual displacement came in at 385 cubic inches due the the 4.04" bore. This engine features the following: EngineQuest 220cc /72 cc straight plug heads,hydraulic roller 231/239 @ .050" 110 LSA ,Scorpion 1.65/1.5 roller rockers,10-1 comp, Air-Gap dual plane, 750 Holley Dbl, 1 3/4" Hedman Hustler's, and Esso 91. So going from memory only, as I don't have any dyno sheets here to look at I will try to keep the results from becoming to convoluted. We tested this engine with two carbs (customer's 750 and the shop 830 HP) and no less than three sets of headers. The influence headers can have on the output of an engine were eye opening and interesting to say the least. First up the engine was initially fired and given a lengthy break in cycle with the 830 carb and the shop's set of Schoenfeld dyno headers with Magnaflow mufflers. Peak output was 480 hp @ 5900 rpm and a fantastic 493 lb/ft coming in @ 4400 rpm. Next round of testing involved the customers  used and abused 1 5/8" chassis ('81 Camaro) headers with no mufflers and the 750 carb. Peak numbers were 445 hp @ 5800 rpm and 480 lb/ft @ 4300 rpm. After receiving the new Hedman's featuring 1 3/4 diameter primaries they  were bolted on and testing was resumed. Power was a pleasant compromise between the full race dyno header and the smallish chassis headers. The engine was now producing a solid 474 hp @ 5900 with torque also in the 470's. What the numbers don't reveal is the "personality" of this engine. The engine fires with a touch of the starter button, idles easily with a little lope and due to the slick hydraulic rollerized valvetrain makes zero mechanical noises.It is also extremely consistent while making best power with only 32 degrees total timing. Easy going and laid back with a speak softly and carry a big stick temperment is how I'd describe this engine. It was built to be a bulletproof dual purpose engine and I think it is a success on all accounts. Here's couple of shots and dyno vids for those that like that sort of thing. J.Rob

1 comment:

  1. Be sure to include the bails with the steel covers. And the studs, barrels, O-rings and what-not with the aluminum covers. Their thermal emissivity is equally easy to check, especially if you have one of those IR thermometers. Most impressive of all is an IR photo. Just put an aluminum cover on one head and a steel cover on the other. Saves you a thousand words.Aluminum Valve covers

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