The Stovebolt Site Forums The Shop Area Engine Shop How Many Horses

I remember the 1967 Malibu/El Camino equipped with the 327 cu.in. that was offered in 250 and 300 horsepower. Cannot however remember how to tell which is which. Can this be determined by the VIN, a tag somewhere or by a number located on the engine itself. Any code #'s or other factors would be helpful. Thanks in advance.

To identify the engine and heads, go to www.mortec.com This site tells you where to look for the casting number locationss.

Iirc, the way to tell the higher horse engine was from the front of the head. Should be two "camel humps" on the 300 hp head.

Fred, thanks for the link aned will check it out. I do remember the double hump heads but was thinking they signified fuel injection application. Cannot remember if they were used on the 300hp carbeurated (sp) engines. Would the 250hp engines have the single or no hump heads?
Thanks again

Bruce, If I remember right the other obvious difference was the 300hp had a Holley carb.
Larry

The original "camel hump" heads were used on 300 HP 327 engines, with a carter AFB carburetor, I think. They were also used on the fuel-injected engines, hence the "fuelie head" name. They have 64CC combustion chambers, and give about 11:1 compression with the factory .100" domed piston. The 250-horse 327 had 10.5:1 compression, with a flattop piston and a slightly larger combustion chamber. Either engine would present problems with today's gasoline. Even 93-octane gas would detonate holes in the pistons with compression ratios that high. Even with very smooth combustion chambers and an ideal piston shape, about 9.5:1 is max with pump gas. 9:1 is better. Unless you're racing, forget about the camel-hump heads!
Jerry

I thought the Camel Hump 327 was a 350 horse engine in the Corvette. The "regular" 327 without those heads was 300 horse.

...Or could that have been because of the cam?

I've seen dummies pay outrageous prices for a set of heads with those big humps on them, when a set of regular-production 305 heads will make more compression, and horsepower with just a little tweaking! People GIVE me 305 cylinder heads to get rid of them, and I install oversize valves, and do a slight pocket-porting job, and turn out more power on the dyno than the double-hump type.

Another sneaky trick is to use a set of low-compression heads from a 350, with 76CC combustion chambers, and do a .100" angle-mill job, where .100 inch of material is milled from the spark plug side of the head, tapering to nothing at the intake manifold side. The resulting chamber volume is 60 CC, more compression than a double-hump head. Add a 2.02" intake valve, and a 1.6" exhaust, plus pocket porting, and they make more power than the double-hump types. I've confirmed all this with temperature and humidity compensated dyno runs, not guesswork!
Jerry

Back on the 327 question; I'm thinking that the 250 and 300 HP engines were dropped around 1967, re done as the 275 Hp 327 with a Q-jet with slightly less compression.All these engines used the same cam,the so called 283 Power Pac hydraulic cam, pretty mild item.The 250 hp 327 used the 283 heads with Carter WCFB.

A friend way-back-when had a 64 Chevelle that had a 275 horse 327, but it may not have been original. On the cam question, my dad's Motors manual from that era listed a whole bunch of different cams, but that manual is long gone. It would be interesting to get into an older manual and acrually look this stuff up, but I don't have one detailed enough that it lists things like cam profiles, or head specs. Does anyone else?

Boo Radley

I've got service manuals from Mitchell, and a few from Motor that go back into the early 60's. They won't list all the options, but there will be a pretty good cross section of the available high-performance stuff. The GM performance guru from the 50's through the early 80's was Zora Arkus-Duntov. Among his early accomplishments was the development of the "Ardun" overhead-valve cylinder heads for flathead Ford engines. Most of the high-performance Chevy engines had Duntov solid lifter camshafts, which were identified by the last 3 digits of the part number. The "078" cam was used in the 265 Corvertte engines, and the "098" cam was a solid-lift option on the 283 and 327. The 098 was also known as the "30-30" cam, referring to the .030" lash adjustment it required. That made it very noisy, a sure sign the engine was running a solid lifter cam! They ran like stink, though!
Jerry

The original 265 V-8 was built as a low cost engine for the least expensive car GM offered.It's lightweight casting and cheapo stamped rocker arms on ball studs were cost saving measures.The fact that 50 years and 100 million small blocks later, it's still a viable racing piece is amazing.Smokey Yunick did a lot of work for Chevy on the early small blocks.Engineers found it easier to deal with an outside contractor than the eccentic ladies man that Duntov was.But Duntov did get Chevy to make in house changes eventually.Duntov wanted overhead cams,Yunick wanted a taller block and longer rods, neither guy got what he wanted.
Boo, the 64 Chevelle originaly had a 220 hp 283 as the top engine option,later in the year, the 250 and 300hp 327 became available.

Actually Truckedup, now that I think about it, that guys car was a '65 Chevelle SS. Boo

327 engine 1965, 250, 300 and 350 hp,later in the year, a limited run of 396 cars