What should I do?

Discussion in 'Street/strip 400/430/455' started by johnriv67, Oct 1, 2019.

  1. PGSS

    PGSS Well-Known Member

  2. 71stagegs

    71stagegs bpg member #1417

    Anyone remember the weight savings going to a aluminum intake Wizard?
  3. Bens99gtp

    Bens99gtp Well-Known Member

    I think its 50-60ish for the pair..........du . I was think and read heads in my head:confused::rolleyes:
    Last edited: Oct 5, 2019
  4. Philip66

    Philip66 Well-Known Member

    Stock intake is @ 50lbs.
    Aluminum is @ 22lbs.
    Donuts & Peelouts and Gallagher like this.
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    That's the Edelbrock DP intakes. I believe the SP1 weighs more.
  6. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    I would hand lap the valves on any head used or new before they went on my car
  7. Bens99gtp

    Bens99gtp Well-Known Member

    Seeing those heads have been cut .040 make sure you take the time on assembling to make sure the ports line up when bolted together..........you will more than likely need at least a .060 thick intake gasket... maybe more........maybe have to have the intake angle trimmed.

    With the composite gaskets you will really want some form of valley splash pan. Can cut an old stk valley or get an amp pan.

    You will need different pushrod lengths as well
    johnriv67 likes this.
  8. johnriv67

    johnriv67 Well-Known Member

    Thanks for the good info Ben. I’m actually hoping I messed up the valve lash with my first set of pushrods badly enough that these same ones will fit, but that’s not likely, hence why I’m searching for adjustable ones. :D
  9. Bens99gtp

    Bens99gtp Well-Known Member

    I would just buy 1 checking rod and measure and order a set to fit......much easier than having to get 16 set right and not come loose
    Smokey15 likes this.
  10. johnriv67

    johnriv67 Well-Known Member

    I actually forgot about checking and setting all 16, you’re right that’s a much better plan that I also did the first time. I’ll probably do that again then.

    Also, in the picture above of the B4B, is that a very early spread bore style and should I mill down the divider?
  11. BQUICK

    BQUICK Well-Known Member

    Just use a 1/4 open spacer....does the same thing as milling. On my B4B, Tomlinson put a removeable divider in.....pretty cool. Easy to change it and see difference.
  12. johnriv67

    johnriv67 Well-Known Member

    As always, I'm doing research and I fear detonation with these heads, especially running on the ragged edge of 8:1 dynamic compression. I hope I will be able to run them fine, but if I experience detonation, what amount of timing should I pull out or what else should I do?

    I'm also running steel shim headgaskets, so unlike the felpros the thing that will die first is the damn pistons instead of kicking out a gasket.

    It has to run on 93 or I suddenly have to take everything back apart again.
    Last edited: Oct 12, 2019
  13. Schurkey

    Schurkey Silver Level contributor

    Are you sure about your compression ratio? Seems on the high side, but I haven't worked the math. WHAT PISTONS are you using?

    Far as I know, the danger area is between ~.050 and about 0.100 for quench/squish. Too wide for decent turbulence, too narrow for flame travel. Above 0.100 the flame front can burn the end-gasses. Not real efficient, you have lazy combustion and need extra spark advance. Tighter than .050--and preferably more like .040--there aren't enough end-gasses in the quench area to be concerned with; turbulence goes up, burn speed goes up, spark advance requirements are moderated.

    "I" would deck the block, and/or get taller pistons, and/or get a little extra stroke on the crank via offset-grinding. Offset grinding gets the piston higher in the cylinder AND adds a few cubic inches to the displacement, but reduces bottom-of-piston to crank counterweight clearance. You probably won't get .050 extra height, though. You might get .030, but that'll depend on the condition of the crank now, plus the availability of .040- or .050-under bearings; and the piston-to-crank clearance. The least-expensive option is probably decking the block. You could cut .030 off the deck IF (big IF) you could re-use the steel shim head gaskets. .020 in the hole, plus .020 head gaskets = .040 quench, and that'd be lovely.

    At some point, you'd take enough off the block--and the heads have already been cut--so you're going to need really thin intake gaskets, or shave the intake manifold, or--my preference--shave the intake face of the heads to make up for the amount cut from the head gasket surfaces of the block and heads.
    major_mitt likes this.
  14. johnriv67

    johnriv67 Well-Known Member

    Ok thank you, I have the stock 67 430 pistons with the 16cc dish and will be running that with about .070 quench. If I go with the felpro gasket the quench jumps to .090 but I’m safe with the compression ratio. Is there a happy medium?

    I don’t want to deck the block quite yet, and have no plans to remove the engine unless I have to.
  15. Schurkey

    Schurkey Silver Level contributor

    Lots of octane, wild cam, Sohmender Singh grooves, Papal Blessing, ceramic coatings, 160 degree thermostat (or colder) Holy-water and methanol injection, and lotza luck.
    1970stage1455 likes this.
  16. Gary Bohannon

    Gary Bohannon Well-Known Member

    Before buying any heads, I would lay a strait edge across all the valve stems and check on any variation.
    Cant fix rocker arm geometry if stems are different heights.
    Rocker shaft height is just as critical as push rod length.
    There is more involved in inspecting heads, but level and even stem heights are a good clue that all is well.
  17. johnriv67

    johnriv67 Well-Known Member

    That’s a very good point. I picked them up today and just put a straight edge across both heads. There’s a variance of at least .035 between the straight edge and top of the valve stem on several valves
    Last edited: Oct 14, 2019
  18. Gary Bohannon

    Gary Bohannon Well-Known Member

    WOW. .250 ! Grinding a valve will raise the stem height. Grinding the head seats will also raise the stem height. Valves can also "sink" during use, and raise the stem height.
    If valve stems rise, the center of the rocker arm shaft must rise an equal amount.
    Adjustable push rods, (or adjustable rocker arms) and spring shims will not correct a Buick shaft style rocker arm geometry issue.
    I would talk to a Buick machinist.
    Last edited: Oct 14, 2019
  19. telriv

    telriv Well-Known Member

    Your saying that you have 1/4" diff???? & not .025"????
  20. johnriv67

    johnriv67 Well-Known Member

    Can I use stock 430 rocker shafts and rockers on these 70 heads?

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