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SS454 rear wheel dyno test?


Grant MacPherson

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Has anyone done a chassis dyno test on a stock 360 hp 454? AND is it done in 3rd gear WOT?

Stock except rear end changed from 2:56 open to 3.42 posi Just something I thought I would try to check if the engine is preforming as  it should. What numbers should I be looking for?

WAS THINKING OF RUNNING TO 5200RPM    I DON't  whànt to blowing it.  It is running great, showing 90,000 original miles.

Comments,suggestions? 

Thanks, Grant

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  • jft69z changed the title to SS454 rear wheel dyno test?

Prior to 1972, horsepower was rated in gross numbers. I'm guessing that 360hp gross will net out to somewhere in the high 200s or maybe 300 horsepower max once it goes through the driveline to the rear wheels. It will however be a torque monster. 💪 5200 RPM is reasonable and safe for a big block in good condition. I think you can safely wind them up to 5600 or 5800 RPM but personally, I wouldn't do that regularly.

Dyno pulls are done differently for different reasons but yours would likely be done in top gear WOT.

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Grant, Are you doing it to Dyno tune for optimal performance or just for numbers? A good experienced “old school mechanic” or engine builder can do that for you with their Dyno. As far as numbers, there are many factors that play into it. Like Bryan said, horsepower and torque were rated in gross numbers. Most vehicle manufacturers underrated them for insurance reasons. Back in the day when Chevrolet produced and came up with these numbers, it on a free standing engine dyno vs roller Dyno. Were headers or manifolds used? Fuel type, leaded high octane fuel that was readily available vs today’s ethanol non leaded premium with lower octane? We’re they tuned for performance or factory settings? As for the Dyno machine ratings, meaning how “conservative” or correct are the numbers for that particular machine? Some of today’s Dyno’s are underrated as much as 15-20 percent. As far as the LS-5 454 engine and camshaft, it was designed for low and mid range torque to move the approximately 4000 plus or minus pound Monte around depending  on the installed options. The majority of big block Monte’s were heavily optioned with AC and all the other power goodies. Just some things to consider when comparing the numbers of “old vs new”. 

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I've often wondered what the old engines "actually" make, given the factory ratings were sometimes underrated, or simply rated at a certain RPM, while the engine was actually continuing to climb in power.  My LS5 seems to run out of steam closer to 4500.  I'm taking my LS7 to Westech on Tuesday for an out of car dyno and tune session, and am very interested to see what it actually does.  Let us know on your chassis dyno numbers !

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Group, I'm back from Westech after a very successful dyno session with Steve Brule. I have a few pics, and a few videos. My question is whether I should start a new thread, or just post here. The engine was run out of the car.  The issue with the video is size. I have a short 4 second vid that's 16MB, and a longer 15 second vid that's closer to 55MB. Am I able to upload that size here?

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