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235 Blue Flame - 3/4 race cam

Discussion in 'The Hokey Ass Message Board' started by striper, Nov 12, 2008.

  1. striper
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    striper
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    I met an old guy at the parts shop this morning who just finished a '40 Chev. He was talking about building another engine and some speed equipment he has for it. But he said he didn't know what cam to use. He said no-one has a 3/4 race cam for 235s anymore. I know nothing about them but said I found it unusual given their popularity in their day.

    Can anyone give me info on what's available so I can pass it on to him?

    Pete
  2. HEATHEN
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    HEATHEN Member

    Iskenderian still sells cams for 235s. So does Patrick's in Casa Grande, AZ (I believ he sells Howard's cams). Nielson Cams will regrind his original cam. You mentioned a '40 Chevy; if it's still got the original engine, I doubt that Isky or anyone else has a core for it, since Chevrolet enlarged the cam journals in 1954. If anyone wants a hot cam for a '37-'53 engine, they'll probably have to have their stock cam reground.
  3. Human Fly
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  4. Stovebolt
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    Stovebolt Member

    i've spoken to them about my 6's too.

    did you know they developed the XU1 cams with holden, so they know a thing or two about 6's and cams.

    They do Flathead cams for one of the flathead boys in victoria, so "Do yourself a favour .......!";)
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  5. Snarl
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    Snarl Member

    For starters, you need to know what year the engine is.

    Clifford does/did offer camshafts for the small journal engines.

    Howard F298 should still be available for the later large journal engines. Try Patrick's for that. I have it in my 261, and with the right gearing it is a nice cam. It's about as big as you would want to go for the street without having to notch the pistons. Careful about how much you deck the block and mill the head also.
  6. Road Runner
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    Road Runner Member

    Patrick's offers cams from Delta Cams in Tacoma/Wa.
    If the original cam is still in good shape, Delta will regrind the original cam to whatever grind pattern they offer for about $50.
    Give them a call - they really know cams for these engines and have excellent service.

    Delta grinds have a lot less overlap than the original Chevy and old Mcgurk race grinds and are more symmetrical.
    I have their 254 advertised duration in/ex grind on my 261 (.060 bored, 9.0 cr) which holds torque up to 3000 rpm and gives peak HP around 4000 rpm.

    To get good HP above 4000 rpm on a well breathing and built 235 get at least 264 adv. duration at the exhaust. If you keep the intake at 254 you still get good idle and low end torque for the street.
    The 254/264 in/ex 'Bulldog' grind is very popular for the later full pressure 235s and is also offered by Tom Langdon.
    Last edited: Feb 7, 2010
  7. gas pumper
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    gas pumper Member

    Patrick knows his stuff, he recommended a cam for my 235 back in the early 90's, a Howard. Maybe M4F? Anyway, it needs to idle a little high, like 800, but will pull great off idle and run strong to over 6000, but seems to not help ET to run over 5000. You can chug around town at 1000 in high if ya want to be quiet. A great cam.
  8. Road Runner
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    Road Runner Member

    Patrick's used to carry the M4F howard cam which is very similar to the stock 261 grind.
    It's recommended for the earlier pre-54 235s but doesn't do anything for the later 235s.

    Sounds like you got a hotter cam than that in yours.
    Patrick's doesn't offer Howard cams any longer, as they don't offer cams for these engines any longer.
    Not sure about that.
  9. TagMan
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    The term "3/4 cam" really has little to no significance. Back then, there was very little math / science involved in the aftermarket cam business. It was trial & error development - a cam shape found satisfactory for street performance, but not as "hot" as a "full race" cam racing, was called a "3/4 race" cam.
  10. repoguy
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    repoguy Member

    Whenever someone, when referring to their ride, has ever tried to tell me that it had a "3/4 race cam", that's pretty much been a solid indicator that they are completely full of shit.
  11. panic
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    panic BANNED

    Whenever someone, when referring to their ride, has ever tried to tell me that it had a "3/4 race cam", that's pretty much been a solid indicator that they are completely full of shit.

    For an owner this is generally true - the same person will tell you "it's bored and stroked" - he has no idea what that means, and doesn't know that you do.

    OTOH, if it's just an enthusiast, they're repeating what they heard from someone who hasn't been under a hood for 40 years.
    I've been doing this for a long time, and that was a dead giveaway that you weren't in the loop in 1964.


    BTW: you should tell the cam grinder about anything you're doing to the engine (compression increase, replacement pistons, high-lift rockers, big valves, split exhaust) or chassis (4 speed, automatic, stall speed, axle ratio) to get the full benefit of his experience.
    Last edited: Nov 14, 2008
  12. Mr. Creosote
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    Mr. Creosote Member

    Is there a rule of thumb for the fraction of the cam? I know its meaningless but couldnt you say cams in the 260 duration range would be 1/4 race.. 270 range duration 1/2 race.. 280 range duration 3/4.. 300+ would be full race??
  13. repoguy
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    repoguy Member



    You should start a separate thread.

    A lot of guys around here with inline Chebbies.
  14. 6inarow
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    6inarow Member

    Is anyone out there interested in a product I'm working on?
    Direct replacement high performance intake valve for the 216/235/261, better flow, lighter weight, larger head diameter than the original, no special machine work required to install, fits the original valve guide, uses the original spring, collar and locks, length adjusted for high lift cam.[/quote]

    How is that going to help the head flow better?
  15. gear jammer
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    gear jammer Member

    235 chevy? runs strong to over 6000 rpm?, we must be talking about another motor!
  16. FATT STRIPES
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    FATT STRIPES Member

    as i was reading this thread this was the first thing that came to mind.
    i remeber several times in the parts store when , what the board refers to as "gold chainers" would ask for a 3/4 cam. i had no clue what they meant
  17. gas pumper
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    gas pumper Member

    No I ain't bullshitting ya, .050 off the head, .050 off the block. 848 head a little cleanup in the ports. Neway cut valve seats, .060 over bore. flat tops, Total Seal rings, M4F cam, big cap HEI, full flow oil filter, Fenton headers. Offy intake w/ 2 "B" Rochesters.

    There was a video on the Hamb last year of me running at Island against the Gold Duece, All you could hear in the sound was my 6:D, all the way to the end of the track. And the 32 is a little hemi with open headers.
  18. HEATHEN
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    HEATHEN Member


    It's just an archaic term that actually was used by some cam grinders in the '40s/'50s. I've got a N.O.S. Wolverine regrind for '55-'56 Chevy 265s that proudly declares that it's a "3/4 race" on the box. Its modern equivalent is an RV/torque grind, more or less.
  19. striper
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    striper
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    Yeah guys I know the 3/4 cam thing is a generic and very non-specific term. I did say this guy was an old guy and I think he is basically a restorer. I didn't go into the specifics of his motor or car for that matter but figured it would probably be easier to get some info for him on here than for him without this great resource.

    Oh, for those who asked the motor is a 56 or 7.

    I guess if the guy knew about cams and motors in general he would already have known that he could go to a local grinder like Wade and specify what he wants. The fact that he doesn't does not mean that he shouldn't be allowed to put a cam in his car that will give him some performance and that I shouldn't ask the question on his behalf.

    To you guys who offered some solid information. Thanks. I'll follow up some of the leads and pass them on.

    Pete
  20. panic
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    panic BANNED

    Of course, you're right.
    How could that possibly help.
    What was I thinking.
  21. striper
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    striper
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    Did you offer solid information? Yes? Then the thank you applies to you doesn't it?

    Would you like something more?
  22. Human Fly
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    Human Fly BANNED

    Then maybe he should just go and ask for a cam with better performance than stock, instead of trying to get information from here, and pretend he knows what the fuck he is talking about. Sounds like he wouldnt know the diff anyway.......
  23. striper
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    striper
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    Fuck me!

    I thought this place was about helping fellow enthusiasts out. I know it used to be. That's all I'm trying to do.

    I bumped into a guy who happens to be into old cars. Not that common where I live. I started chatting to him. I don't give a flying fuck whether he knows about cam shafts or not. And he didn't ask for my help or yours. I thought I could help out a nice old guy because I have access to this (USUALLY) very helpful network of knowledgable guys.

    What a fucking bunch of superior fucks you are. I couldn't tell you the first thing about the best cam for my motor. It's not my area of expertise. Now go and have a look at the car I'm building and tell me I'm not a hot rodder.

    If you have some information and would like to help then I am more than happy to hear from you. (and many have, thanks) If all you want to do is show us all how clever YOU are without contributing very much at all then start your own thread and tell everyone that wants to know. Can I suggest a title, "Let's talk about me"

    Pete
  24. Human Fly
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    Woooooohhhw there Tonto!
    I am not saying I am anything, I just offered you some information, thats all. Your the one making the smart arse comments about the information. I my books, any information is good when you know little........thats why your asking right.
    Dont get your back up, I was just trying to help.
  25. striper
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    striper
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    Hey I didn't make any "smart arse" comments. I just defended the guy's right (and mine) not to be a camshaft guru. There is a whole aftermarket industry out there built on guys that don't know what performance part they need or don't have the ability to build it for themselves. If we all knew all there was to know about building engines and cars I'm sure none of us would be on here. That's why I get pissed off when people would rather pass judgement on a guy for his lack of knowledge than educate him.

    Pete
  26. Dick Dake
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    Dick Dake Member

    Ladies, easy now. Find the model of the cam, give a cam grinder the purpose and specs of the motor you are building, and have him do it for you. They are good at it, that's why they do it for a living. Find an Oz cam grinder and let him do it. Most cam companies in the 40's and 50's had different 3/4 race cams. That is all.
  27. RichFox
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    When I was a kid 3/4 cams and 3/4 race were common in usage. As has been said here, now they would be called am RV cam. But when I started buying Hot Rod parts for my Olds Isky had an E4 which was sort of a hot 3/4 race cam, the E2 which was a full race cam and the 5 cycle which was a "Super Race Cam" They had to have something to discribe different grinds to people all over the country who were reading adds in HRM and didn't know anything about cam timing.

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