This would then become the "240hp" setup available from the factory in Corvette form. Chevrolet didn't officially call this a 1 hp per cu.in. engine, but a representative from Chevrolet told McCahill that it was so.

So how does 240 HP out of 265 CI equate to 1 HP/CI??

 

If you're asking me, I'm only reporting what I read and arriving at a conclusion.

 

Are you sure they weren't referring to the then soon to be released '57 model (model changes were in July) that would have had the 283HP / 283CI Fuel Injected options?

HRJ

 

I have reviewed the article (Mechanix Illustrated, June 1956, p. 86-) with that in mind and can report back to you that McCahill is referring to the 265 cu.in. engine and has photographed and is test driving a 1956 Chevrolet 150 two-door sedan.

There is no mention of the 1957 Chevrolet.

 

McCahill claims you can gain 15-25 hp when you loose the fan belt, for which 1956 RPO 411 had a reputation. But since McCahill as a judge disqualified 1956 Chevrolets at the speed trials for this reason, I would be led to believe that he took that into consideration in his writeup.

 

Maybe McCahill is just bad at math.

 

McCahill was the biggest automotive blowhard of the 60s-80s, may even span another decade or two.

Maybe the fan belt just fell off.

 

I'd tolerate the nickname "blowhard" for a job like that for 20+ years. Where do I sign up?

 

I have an original '56 slick brochure, 22 pages in all. Someday I'll scan it into a .pdf file.

The most powerful engine available in a full-size Chevy in 1956?

Corvette V8
Valve-in-head V8 engine. 225 h.p. at 5200 rpm; torque, 270 ft-lbs at 3600 rpm. 265 cubic inch displacement. 3.75" bore, 3.0" stroke, 9.25 to 1 compression ratio. Dual four-barrel carburetors, two oil bath air cleaners, special high-lift camshaft, high-speed mechanical valve lifters, high-power exhaust headers, dual exhaust system.

COPYRIGHT 1956 -- CHEVROLET MOTOR DIVISION, GENERAL MOTORS CORPORATION.

 

Yes, that is true for the beginning of the model run. But into the model run, all major top-end castings changed for this engine and two different horsepower ratings were offered.

According to Chevrolet Technical Service Bulletin DR #270 dated November 8, 1956, the dual 4-barrel engine could be fitted with a regular camshaft or with a racing camshaft. The engine number suffixes were "GR" and "GU", respectively for the Corvettes, and "GS" and "GT" respectively for the passenger car, according to this bulletin.

Remember, engine number suffixes are stamped at the factory. The factory was building two different 2x4's: regular versions and racing versions.

I am assuming the racing camshaft was a high lift camshaft with solid lifters and was a design indended to modify a horsepower rating, but the only source I can think of right now that would confirm this is Alan Colvin's Chevrolet by the Numbers p.71: albiet a book full of errors, but imply that these two engines were rated at 225 hp and 240 hp (depending on the camshaft). I cannot find a Chevrolet factory source that delineates horsepower between otherwise identical engines but fitted with regular camshafts and racing camshafts.

This is why McCahill apparently can make this claim through Chevrolet's "grapevine": it wasn't being broadcast through the public.

Unpublished changes abound for 1956, so not finding a factory glossy on the issue doesn't mean it does not exist. For instance, find a factory glossy detailing the new Spring colors Colypso Cream, Grecian Gold, and that new gray shade whatever they called it. The original glossys do not include the new padded dash and safety belts because they were introduced mid-year. The same holds true with these engines. The factory color glossys don't exist.