Thursday, October 08, 2015

this might be more than incredible engineering, it might be genius, 597 hp from a 318 poly (1962-65 small block)


It strikes me as incredible because the 318 poly has been regarded as useless for, well, since it was made. No hi perf parts support, no good stock parts interchangeable with other Mopar small blocks (except cranks). It's an ugly stepchild.

But... on the other hand, its got polysphere heads and pistons... is dirt cheap, and no one has ever tried to do anything with one! So, instead of another bellybutton sbc, here is a one of a kind overcoming of the intrinsic problems with a forgotten motor.

To make a silk purse out of a sows ear, is an old ugly saying, but you might get the idea. The AMSOIL Engine Masters challenge finally impressed me. I usually just keep flipping the pages to something interesting, as I really don't care about more engine builds only really rich people can afford.

To get 597 hp out of a lame small block with no aftermarket intake manifolds, Chris Bennet, Anthony Kinney, Corbin Dale, Travis Hilger bumped the compression to 13 to 1, punched it out to 402 cubes with a 90 over bore, found out a Hilborn injection system for an LS7 fits, and ported the heads.

Thee heads happen to be as efficient as 426 hemi heads, and superior to the 340/360 and 383/440 heads, very close to the theoretical limit of an unsupercharged engine

If the Mopar figures as found in the Plymouth factory manual are to be believed, torque of the poly 318 was 345 lb.ft. Now, take torque and divide it by cubes, then multiply this by 151, and you get brake mean effective pressure (bmep, proportional use of the charge coming into the engine).

the Bmep of a poly is 164, that of the 426 hemi is 173

Full story at http://www.hotrod.com/events/1510-vintage-mopar-power-550hp-chrysler-poly-318-v8-on-the-dyno/

David emailed me (thank you !) to let us know that Poly parts and 357 and 402 Stroker Kits can be bought at site: http://chryslerpower.com/webstore/Poly  Performance intake, valve covers, cams, a small stroker kit (357 cid) and the infamous TTI 1-3/4" primary headers.


http://www.1962to1965mopar.ornocar.com/poly318.html  for all there is to learn about beefing up a poly

http://www.mascotgraphics.com/belvedere.htm for a Willow Springs racer 1965 Belvedere II with a poly

https://www.facebook.com/polysuperpac

But nothing is likely to top Barney Navarro getting 700Hp  from a AMC straight 6, Barney is of course a legend, and an engine master. http://justacarguy.blogspot.com/2013/02/700-hp-199-cu-in-amc-rambler-straight-6.html

4 comments:

  1. Great article. I have always wondered how much power you could get out of weird motors. I'd like to see someone do the same thing with and International Truck motor, a GMC V6, a Studebaker engine, etc. Also, while it's understandable while uncommon motors are seldom used for high performance applications, why do so few people build high performance versions of the Ford 351/400M? There's plenty of those out there.

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    1. thanks! I think that is the 1st time anyone ever commented "great article!"

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    2. The 'build whatever the forum tells you to' aka swap in an LS culture seems to be killing off the old methods of actually understanding how engines work. No one seems to be learning the theory and tools to take any motor, including an awesome oddball like the Poly, and getting some power out of it with 100% more cool points.

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    3. yup, hot rodding has drastically changed since Vic Edelbrock and his contemporaries changed model As into cool cars

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