Advice needed on a 472 build

Discussion in 'Big Block Cadillacs' started by kamtile, Jul 14, 2017.

  1. Darius

    Darius Well-Known Member

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    I've read and then reread the above posts and just want to add my support to what member 3508 and Julius have said about the benefits of good heads. That is especially true when it comes to having otherwise stock heads being ported by someone who means well, but who lacks experience with Cadillac heads.

    A good friend of mine, now deceased, had worked much of his life in the automotive performance industry. His work history included all phases of automotive machining, parts distribution and key to this posting, the use of flow benches. Over the years he had been deeply involved in porting both Chevy and Ford heads, always using flow benches to verify that any changes made provided the desired result. My friend undertook to do a basic pocket porting job on my first set of 120 cc, late model Caddy heads. Bottom line was, when done, I had LESS flow than I've seen for any other "stock" head, using the same standard depression of 28" of water. What had worked on Chevys and Fords did not do the trick with the Cadillac heads.

    My Cadillac Flow Numbers Done by XXXXXXX

    "This is for the intake with a standard stock valve, slightly ported in the bowl. We could gain more with work and the Milodon Mega Flow valves.

    .100 .150 .200 .250 .300 .400 .500 .600 .650 .700

    64.9 92.5 120.1 140.3 158.2 190.6 217.4 232.8 236.9 240.9

    ****************************

    This is the exhaust pocket ported in the bowls with a stock exhaust valve

    .100 .150 .200 .250 .300 .400 .500 .600 .650 .700

    52.7 74.6 94.1 110.3 124.9 146.0 160.6 172.8 175.2 177.7

    This one is when we installed a larger 1.770 exhaust valve and re-ported to match"

    .100 .150 .200 .250 .300 .400 .500 .600 .650 .700

    58.4 77.9 97.4 117.6 133.0 157.4 181.7 196.3 198.8 201.3


    I support the position that anyone building a solidly running, better than stock, Cadillac engine is GENERALLY better off either buying heads already ported by a competent Cadillac vendor, or in purchasing New Aftermarket heads. Save your time, save your nerves, save you money.

    Best,

    bro. d
     
    Last edited: Aug 23, 2017
  2. 8ad-f85

    8ad-f85 Well-Known Member

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    I support the post in sentiment, but it would be better to illustrate that point if you had a flow sheet using larger valves than stock intake.
    The bowl is already big for a stock valve.
    The stock valve size barely leaves room for adding angles for the VJ let alone making the bowl bigger.
    Just the addition of the larger intake valve and appropriate VJ angles improves the head.
     
  3. Darius

    Darius Well-Known Member

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    8ad-f85,

    I'll accept your post, if only in sentiment. :D

    These numbers and italicized comments were simply cut and pasted from a file many decades old. There was nothing additional to add. No flow sheets, no comparison of bowls or any other thing. The guy who did the porting and whose comments I pasted above is dead and I've found it difficult to glean any further comments from him. Sorry.

    bro. d
     
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  4. mario

    mario Well-Known Member

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    "and I've found it difficult to glean any further comments from him. Sorry."

    Bro d:
    I thought you had connections in HIGH places!!!!!

    Ciao,
    Mario

    P.s.: stop talking about head.
     
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  5. 8ad-f85

    8ad-f85 Well-Known Member

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    Hopefully not too far off tangent but for the discussion's benefit.
    I've embarrassed myself by carving up a duplicate 300 cfm sbc head into another casting just to see it fall 50+ cfm short...all because I hadn't copied the chamber EXACTLY.
    A week's worth of work might as well be in the trash...along with my shorts.
    The relief of seeing it come back wasn't worth the years of life I stressed off myself in the meantime.
    I don't mean to casually play off how easy airflow improvements are. They aren't always.
    Sometimes it's hypothetical or just potential.
    The internet world can be fantasy.
    There are many 'ported' chevy heads advertised in the 260 cfm range that are 225 at best.
    I suppose those didn't include spark plugs. They are extra.
    Those are all of the '600hp' engines everyone has.
     
    Last edited: Aug 23, 2017
  6. kamtile

    kamtile Member

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    Update: I am after a milder build than I originally planned, I have gathered most of the parts, MTS #15 cam, Cadco super street small chamber heads, 5200 block, 902 cranks, Edelbock manifold, Jet carb. I have decided against the offset stroker crank grind and wont be using my scat 7" rods or BBC pistons, hoping for 9.0 - 10.0 compression. What would you guys recommend for rods and pistons? Thanks in advance, Keith
     
    Last edited: Sep 13, 2018
  7. nosgood

    nosgood Active Member

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    I'm a big proponent of overbuilding the rotating assembly, even in milder builds like yours. If the budget allows, I'd go for a forged set up. Seems like you have several options from both CadCo and MTS for around $1,000-1,200. Since your engine really won't be turning over 5500 rpm, I would imagine that the stock cast parts would hold up fine. Going forged would just be for peace of mind.

    Cadco: http://cad500parts.com/catalog/page16.htm

    MTS: https://cadillachighperformance.com/collections/engine-parts
     
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  8. Red98422

    Red98422 Member

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    I’ve had a question for a while now, are the prices posted on CadCo’s website accurate? It says that the online catolog is from 2008.
     
  9. nosgood

    nosgood Active Member

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    From what I understand they are still accurate. I purchased all my larger engine parts from MTS though, so I’m no authority on the subject. I’d say just give them a call and ask.
     
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