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Hot Rods 265 cu. in. 240 hp.

Discussion in 'The Hokey Ass Message Board' started by Doodlrodz, Mar 24, 2016.

  1. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    I've been trying to find info on the 1956 265 cu. in. 240 hp. engine and have found an awful lot of conflicting info both in on line searches and from small block lovers on here. So far what I've come up with is that the 240 hp. was a Corvette only option even though there is some mention of this engine being in some passenger cars. I've had small blocks a long time ago '66 Nova, '65 'vette, '68 vette. etc but that was a long time ago so I'm really out of touch with these things, I've been looking at a 265 that the owner has been told by a small block "expert" that it is a 240 hp. I'm finding conflicting info on line as to this claim and would really like to get it cleared up. The engine in question has a suffix on the ID. # of GS which from what I can find is a 225 hp. stick shift dual exhaust passenger car. The intake is 3731394, heads, 3734077, Carbs 2419s, and 2362s heads have the two tower casting. Was the only difference between 225 hp. and 240 hp. the high lift cam? I saw in one search that the 240 hp. was over rated and didn't produce that much hp. So was it just a 225 hp. with a different cam promoted as a racing engine? Any help would be much appreciated and thanks to all who have tried to help out so far, just an awful lot of conflicting info out there on these engines.
     
  2. The 240 HP version of the 265 was intended to be a Corvette only option. The stamped engine code was "GU" for the 240 HP engine, while the 225 HP version had an engine code of GR. These codes would be for engines with standard transmissions. The difference in the engines was the camshaft. The 240 HP version was the first to use the famous "Duntov 097" cam. The '56 version of this cam was for use only in the 265 cu. in. engine due to the oiling notch in the rear bearing journal.
    The heads on both the 225 HP engine and the 240 HP engine were casting number 3731762. However, some of the earliest 225 HP engines used the Power Pack "306" heads. The 3731762 heads did have the two tower marking but there were later 283 heads which also used this same marking.
     
    302GMC and LOU WELLS like this.
  3. The engine codes which I gave in my earlier post, GU and GR, were for these engines for Corvettes. The GS designation would be correct for a 225 HP engine in a passenger car with standard transmission. The 240 HP engine in a passenger car would supposedly have been stamped "GT".
    The intake manifold on all of these engines would have been 3728725 for the earliest 225 HP while later engines would have the 3731394 manifold for both 225 and 240 HP engines. The distributer should be 1110872 or 1110879. I do not know if there was a difference in these distributers or if either was exclusively for the 240 HP engine. The carbs used on the 3731394 manifold were 2414S and 2362S.
    The exhaust manifolds which were used on the later 225 and 240 HP engines were 3731557 (left) and 3731558 (right). These exhaust manifolds were the ones used in conjunction with the 3731394 intake. The earliest 225 HP engines had different exhaust manifolds.
     
  4. The head casting number given in the original post did not make any sense. I have never seen heads with this number, but the number itself looked familiar. The number, 3734077, is actually the casting number for the camshaft for the 240 HP engine. The camshaft part number is 3734078 for the finished cam, but the 3734077 number is marked on the shaft. (The 283 and 327 version of this cam has the "097" number.) So it appears that the engine in the original post may, at least, have the 240 HP cam.
     
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  5. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    Sorry, that was a typo on the heads # here's pix. of the heads & intake etc. image (1) (640x478).jpg image (3) (478x640).jpg image (5) (640x478).jpg image (6) (478x640).jpg
     
  6. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    Here's the carb tags, this the only thing I think we differ on except the cam which I don't have a pic. of. image (2) (640x478).jpg
     
  7. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    OK, now for the big question, what is the difference in value between the 225 hp. & the 240 hp. engines? This one has never been apart as far as I know and I've known about this engine since I was about 12 yrs. old (68 now) only 3 owners it was taken from a wreck in about '57-'58 and installed in a '46 convertible and was sold to the current owner in '94 he has driven it all over the country and just pulled it a couple years ago and installed a rebuilt 283.
     
  8. DDDenny
    Joined: Feb 6, 2015
    Posts: 9,878

    DDDenny
    Member
    from oregon

  9. dudley32
    Joined: Jan 2, 2008
    Posts: 1,882

    dudley32
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  10. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    Haha, I'll print that out and go back and offer him $498.50
     
  11. jimmy six
    Joined: Mar 21, 2006
    Posts: 3,147

    jimmy six
    Member

    Whether they be 225 or 240 this advertised HP fell well short of the other manufacturers in 1956. Dual four barrels were common for most with Chrysler 300+ leading the pack. Dodge at 270 along with Pontiac and Fords at 260. 1956 was the last full year of NASCAR and other sanctioning bodies allow the multi carbs. A single 4 barrel was limit in the first quarter of 57 after Chevy 150's FI's were up front with the supercharged Ford customlines and Chryslers were gone.
     
  12. It would be interesting to compare the casting dates on the block and heads of this engine. The 1732 heads and 1394 intake were not available at the start of the 1956 model year. Also, the 240 HP cam was not available until even later. The cam supposedly first appeared in the Corvettes which were entered in the Daytona speed trials in 1956 and then became a regular production option somewhat later. Again, the information which I have says that the engine code should be GT if it was a 240 HP, standard trans, passenger car.
    For this engine to be a true 240 HP engine, the casting dates would be expected to be no earlier than January 56 or perhaps December 55.
    With regard to value, I do not think there would be much difference today. A complete 225 HP engine is difficult to find (or to piece together). Of course the 240 HP passenger car engine may be a unicorn, which may never have really existed.
     
  13. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,356

    porknbeaner
    Member

    The 225 and 240 horse motors were both 2x4 motors. The 225 could be had in a sedan if you ordered it that way, I suppose you could get the 240 horse motor in a sedan too. I have not seen a 240 horse motor in a sedan but I have seen a couple that I know came that way with a 225.

    The difference in the 225 horse motor and the 240 horse motor was compression, one being a 10:1 ( some books say 10.5:1) and the other being an 11:1 (or 11.5:1) and what GM called an off road cam. Very few 240 horse motors were sold they were primarily a road race motor.

    Here is some information for you that may help this is accurate as far as I know it to be:

    Location Of Engine Code: Stamped on the block in front of the right hand cylinder head.

    Letter Code Engine Horsepower Torque Transmission Carburetor
    FG 8-265 225 270 Powerglide 2 - 4 BC
    FK 8-265 210 270 Powerglide 4 BC
    GR 8-265 225 270 3-Speed Manual 2 - 4 BC
    GU 8-265 240 270 3-Speed Manual 2 - 4 BC
    GV 8-265 210 270 3-Speed Manual 4 BC

    The 270 is a torque number and the HP ranges from 210 to 240, the table didn't transfer well so you may have to strain your brain to understand it but I am sure that you can decipher it if you try.
     
  14. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,356

    porknbeaner
    Member

    I thought that we were talking 265" corvette engine the information that I posted was all 265 inch and they never made a 265 that built 1 horse per inch. At least not from the factory that anyone one of us could have ever owned. ;)

    The compression ratios that I posted were from memory. So I could have been off a point, the real difference between the 225 horse 265 and the 240 horse 265 was compression the cam difference was minimal and the real producer of zot was the compression difference.
     
  15. DDDenny
    Joined: Feb 6, 2015
    Posts: 9,878

    DDDenny
    Member
    from oregon

    You are correct, I fixed it.
     
  16. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 5,082

    56sedandelivery
    Member

    ALL Chevrolet 2 barrel engines were 8:1, ALL 4 barrel and 2 X 4 barrel engines were 9.25:1 in 56. The difference in CR was in the heads used, specifically, the combustion chamber size. The early 56, 4 barrel/dual quad heads were the same 5603 castings, while the later 56, dual quad, 1762 casting heads, had larger ports and shape. ALL had true flat top pistons, without any valve reliefs. The 240 HP was arrived at with a "special high lift" cam, RPO469, a strictly Corvette option Things changed in 57 when some engines did come with domed pistons. That's a fact Jack! I am Butch/56sedandelivery.
     
  17. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    OK, so from the #'s I've been able to find in my searches there were 111 240 hp. corvettes produced and somewhere north of 3000 225 hp. engines both corvette and passenger car. Which I would think the 225 hp. would be worth less, but seeing that they both used the same heads, intakes and just a different cam maybe not???? But for a collector of Corvettes you couldn't very well take a GS engine change the cam and call it a 240 hp. in a corvette. So in that case it wouldn't be worth much other than the heads and intake could be used if you had the right block or fudged the #'s. So what is a 225 hp. worth?
     
  18. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 5,082

    56sedandelivery
    Member

    I've been hunting for a GOOD, 56, 265 block for a few years; all have been rusted up, damaged, POS, that people think are made of unobtanium. I had to "settle" for a 57, 265 block, but it has better features too, such as full pressure oiling ALL the time, and a block mounted starter provision. You have an almost complete, 225 HP, 265. To a restorer, a block can be decked and renumbered; you think that's not done? A cam change then upgrades it to 240 HP specs; the aftermarket can copy a factory cam. Your engine masy have come from a passenger car, but any Corvette restorer would snatch it up just to clone it. Join one of the Corvette forums, and ask what THEY think it's worth; the guys that really want what you have (or about to have). I'm sending you another PM with some info I've held back; someone who CAN answer your questions. I am Butch/56sedandelivery.
     
  19. Doodlrodz
    Joined: Feb 6, 2006
    Posts: 1,406

    Doodlrodz
    Member

    Thanks, I appreciate the help.
     

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