VCCA Home Forums TECHNICAL - 1945 AND NEWER 1955-1957 Duntov cam in a 265

While I'm doing an engine rebuild I want to add a little horsepower to my otherwise stock 265ci 55 chevy. I want to use as many original parts as I can. I believe Chevy used the Duntov cam in the 56 Corvette with duel four barrels. Does anyone know if the higher horsepower version with the Duntov cam was offered in the 55 Chevy and if it will work with the single four barrel. I want to use power pack heads and a single Carter four barrel. Does anyone have any experience with a similar set up using the Duntov cam. Thanks Greg

The original camshafts for 1955 265's were very low lift consertive cams.The sticks had solid lifters and the Power Glides hydraulic lifters. The later sticks also had the hydraulices as there was a problem keeping the solids adjusted and the got very noisey
There was a higher lift solid lifter 1955 cam used in Corvette engines and used for passenger cars for racing. It increased the advertised horse power to 195. Was still a smooth running cam. That cam was also used in the 225 HP 1956 engine and the base Corvettes. There was another special high performance cam made in 1956. It increased the 225 HP engine to 240 HP..Again was for racing in cars and Corvettes. It was considered the first Duntov cam. Had a lumpy idle and reduced the power at lower RPM's but increased power above 4000 RPM and allowed the engine to attain up to 7000 RPM.
In 1957 the next Duntov cam cam was used in the 270 and 283 HP engines....Was even a little more than the 1956 version. That cam was used for many years right up into the 327 engines. There again it will make for a rough idle and poor low RPM performance and would not be recommended for automatic transmission.
Some good hydralic lifters cams were the 1956 265 cam used in all automatics and in all 4 barrel engines. It increased the HP from 162 to 170 in the 2 barrel engine and was part of the increase of th 180 to 205 increase in the power pak engine.
The best smooth running hydraulic lifter cam is the one used in the 1957 283. Was used up to some of the 327 and 350 engines. Smooth idle, could power from 3500 to 5500 RPM, etc. If any 1957 or newer cam is used in a 1955-56 engine the notch must be ground in the rear journal. This meters the oil to the lifters and rocker arms. A larger notch is used for hyd. lifters.
There was a later high performance hyd. lifter cam used in some 327-350 engines but there again it would be a little too much for normal driving in a 265.
Any of These cams will require stronger valve springs than a 1955 used. Also will require the use of pistons that have the notches for the valves cut into the top. If not used the valves will hit the pistons at high ROM's and the valve will drop into the cylinder and blow the engine.
In 1955 the 2 barrel heads and the powe pac heads were the same. In 1956 the P.P. heads had a higher compression ratio. The 1957 PP head had a little higher C.R but the heads have larger ports and the 1957 and up intake should be used.

After sleeping on this I would add-The 1955 4 barrel and intake and exhaust ports would be too small for the increased breathing of a Duntov cam. Actually the cam was used the dual 4 Bbl. for fuel injected engines.
What transmission do you have?

Thanks for the info. The car has the stock Powerglide. The intake manifold and my Carter WCFB are from a little later year. The heads I have are the power pack heads. Gregg

With the Power Glide I would stay with a hydraulic lifter camshaft. Any more than what the 1956 Power Glide cam or the 1957 283 Power Glide cam has would realy kill the bottom end. The 1955 power pac heads are the same as the 2 barrel heads. The 1956 P.P. heads would be a good choice along with the 1956 cam would give you 205 HP, well over the 180 of the 1955 P.P....and remember the stronger valve springs with the inner dampner coil are necessary.