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Thread: What kind of heads are these?????

  1. #1
    396_WAYS_TO_SPIT
    They are closed chambered,large valves,large oval ports with cast # 336781. What kind of heads are these? Are they any good? The guy at the machine shop told me that they were very desirable heads! What does he mean? Thanks 396

  2. #2
    skeepwerkzaz
    Hey neighbor!!!! Well the 781's are NOT closed chamber, they are open chamber. As a matter of fact no GM oval port heads are closed chamber. They are mid 70's 454 truck/car heads. They are good heads and out flow rectangle ports at low-mid RPM's. They also respond very favorably to some bowl work. You can easily make 5-6 hundred horsepower with those heads set-up properly. I have a few books that show exactly what needs to be done to them that I will dig out if you like. Good luck!
    [ August 25, 2002, 10:30 PM: Message edited by: skeepwerkzaz ]

  3. #3
    396_WAYS_TO_SPIT
    Hey skeep, Thanks for the input bro. I am sure glad to meet people so close to me. I live in mesa on university and mesa dr. Email me and I'll give you my number and maybe you could let me read or hear some advise on these heads and other boat stuff. My email is MRFIERMAN78@HOTMAIL.COM
    Thanks, Michael

  4. #4
    Jordy
    Damn, sure is a good thing I moved out of Mesa. I grew up at Country Club and University, mom still lives at Stapley and Main and my old house was at 8th St and Stapley... I have been all around your casa...

  5. #5
    396_WAYS_TO_SPIT
    This is what I found out online.
    336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports
    This is what I sa on Mortec.com's website under cast numbers. What do you guys think?

  6. #6
    Jordy
    Sounds right. I have the same ones on the motor in my Schiada. Took me a minute to recognize the numbers.

  7. #7
    gnarley
    skeepwerkzaz:
    As a matter of fact no GM oval port heads are closed chamber. skeepwerkzaz, I think you might have dis-information. Prior to the introduction of the open chamber heads in 1968 for emissions ALL BBC heads were closed chamber I thought with the exception of medium duty truck or marine, which would include square port & oval port. I might have lost my mind but my 1968 427 390 HP BBC did not have the square port heads that the 425 & 430 HP's had, & mine are oval ports with closed chambers the last time I looked.
    This info is off of MorTec's site
    3931063....68-69...oval..CLOSED..396, 402, 427, 101cc chamber

  8. #8
    blowngas
    gnarley:
    skeepwerkzaz:
    As a matter of fact no GM oval port heads are closed chamber. skeepwerkzaz, I think you might have dis-information. Prior to the introduction of the open chamber heads in 1968 for emissions ALL BBC heads were closed chamber I thought with the exception of medium duty truck or marine, which would include square port & oval port. I might have lost my mind but my 1968 427 390 HP BBC did not have the square port heads that the 425 & 430 HP's had, & mine are oval ports with closed chambers the last time I looked.
    This info is off of MorTec's site
    3931063....68-69...oval..CLOSED..396, 402, 427, 101cc chamberYep---oval port for velocity, closed chamber on a flat top piston = 10 to 1 compression = 91 octane---but it hauls pretty good---stay away from the square port closed chambers unless u plan on running high rpm all the time but not even then---buy a set of merlin steel heads first if aluminum is too $$$$---look for old 60's 396 heads---have fun

  9. #9
    skeepwerkzaz
    Okay,
    So I am a retard. Can't you see I ate too much paste in school? Got a little ahead of myself. The 454 ovals never came in closed chambers. Try not to listen to me too much.
    [ August 26, 2002, 09:19 PM: Message edited by: skeepwerkzaz ]

  10. #10
    Senior Member
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    396_WAYS_TO_SPIT
    My cross streets are the same (University & Mesa). Let me know if you need anything. Can get parts pretty cheap through my old man's shop.

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