What kind of horsepower do you think you would make at the rear wheels if you were making 300 at the engine? My guess is you would lose at least 70-100 horsepower at the rear wheels.

Has anyone seen or built a 300 horse motor without the use of a turbo?

Okay I might not be the guy to answer this but from what I have read flywheel to rear tires will at least be a 15% difference. Don't take my word for it but there is a difference from making HP and getting it on the ground!

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66 Lil' Red Piggie Valiant (Mater Crusher) - Thanks Zilla!!!!! 72 Demon (Number 1 Son's)

I make 260 at the wheel. Depending on the formula and efficiency % used that works to anywhere from 280-320 flywheel.

Lots of people grossly overstate drivetrain loss. They really want to believe they are making big horsepower so they fool themselves into believing 30% was lost in the drivetrain. What matters is what makes it to the wheels. Nothing else accelerates the vehicle. One of the best analysis of drivetrain loss I've read is here: http://www.pumaracing.co.uk/trans.htm

The short answer is 300hp at the flywheel of a manual trans RWD car should be about 250hp at the wheels.

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Joshua

I am seriously thinking about building a 300hp Slant six. I have read a lot of articles and I'm thinking about trying to build a reliable, high horse slant for daily driving. Of course, I know at the same time I am going to have to upgrade the tranny, rear end, suspension and probably have to put wider tires on the back.... But what is the fun in wondering... might as well fo it, eh?

My neighbor finished his 64 Valiant a few months ago and he really enjoys it. He ran a 14.06 at the track before he got it tuned and maybe 200 miles on it. He punched it out .090 over, big valves, a .550 cam, Clifford intake and their heat coated shorty headers with very, very long collectors, and Holley 600 double pumper. It scoots and is very driveable on the street. He even has a spool in the back with 4.11 gears, high stall converter, etc.
Just what you need to go to the Post Office in.....

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Well, not to be a downer but a lot of people come in here talking about how they are going to do XXX hp, and dissapear after their initial thread. However, this is a plausible goal, it is hard to get power out of the slant NA that's why you see a lot of NOS and Turbos. My suggestion would be to do your homework, which I'm sure you've done, build the engine accrodingly and plan on running a NOS system because we all know the dyno's are just mechanical heartbreakers. BIG cam and hyperpak are heavily recommended, Doc posted an engine dyno sheet a while back that accomplished or darn near the goals you are attempting.
Most cars have somewhere between 10-20% decrease at the rear wheels. For our estimation guess we simply multiply the crank horse by .85 to get an estimate of the rear wheels horse.
300hp x .85 = 255 rwhp

Good luck!

We've read a lot of the 300hsp slant stuff too. I'll post something up when we actually start building it cause we've had the same thoughts for our little 63 Valiant...

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Linder Tech.com
Bubba's Trailer Park

Depends on transmission type, converter stall, etc.. I would say a loss of 60 horse at the wheels from a 300 crank horse motor would be average.
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Official Cookie and Mater Tormentor.

Mix "300 hp" and "daily driver" on a slant six, and you're definitely looking at either a nitrous setup or a turbo / EFI combination (or maybe that new Australian blower setup). A naturally aspirated one would rev way to high.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair