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327 90 over or piston marked 06?

Discussion in 'The Hokey Ass Message Board' started by fourspeedwagon, Aug 9, 2013.

  1. I'm working on a 327 for my "fourspeedwagon". It's a '67 small journal 327. I pulled a head off to inspect the cylinders and will probably put on a bigger set of heads I have. Anyway- the pistons are marked "B530" and then stamped either "90" or "06". I've never heard of a 90 over 327 and I've never seen one stamped 06 either. Usually I see .030 or similar. Anybody familiar with those pistons (b530)? They have about a 1/4 inch pop up and a slight eyebrow for the valves. I'll try to post a pic.
    Thanks in advance

    Well, scratch the pic.. I've been getting the same invalid file popup all week when trying to upload

    Isn't conforming to non-conformity still conforming?
  2. Pez
    Joined: Jul 16, 2008
    Posts: 84


    .06 over is as far as You can go on a 327, so I'm led to believe.
    I got hold of a bored and decked 327 block and did some research into pistons etc, any further than .06 and the walls get to thin.
  3. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,738


  4. JeffB2
    Joined: Dec 18, 2006
    Posts: 8,980

    from Phoenix,AZ

    The "B" means Badger Pistons, the 530 is a cast piston copy of the 11.5 to 1's used in Hi-Po 327's.Back in the 70's Badger made these for 302,327 & 350 SBC's and 289-302 Fords I believe they stopped production of these "pop up" pistons in the early 80's they were listed and sold a lot through J.C.Whitney you would need a old 70's early 80's catalog to get more info.I built a 302 & 331 SBC using them "Back in the Day"

  5. I built a 302 Chev in 83 using Badger cast pop tops. Have you measured the bore? Could it be .060 with the last 0 left off? JW
    Deuces likes this.
    Joined: Jul 4, 2006
    Posts: 254


    Don't recall a "B530" Badger piston but there is a "P530".

    The P530 is a forged piece, NOT cast, it is the only forged piece Badger had in it's "performance" line.

    The largest O/S was .060", there were no .090"s available.

    This is the replacement piston with a .125" dome for the higher HP 327's, e.g., the 365" Vettes.

    (Add) I just recalled the "B530" may be the number forged inside the piston, but the part number is definitely P530.

    Thanks, Gary in N.Y.

    P.S. Chances are you may not have a usable block there if it's seen much use and is already at .060"?? Measure the bores! You may be able to run that piston and those bores up to 4.062" with some file-fit rings, but it will be a close call!
    Last edited: Aug 9, 2013
  7. Yep, that's the one Gimp.
    Must be 60 over just stamped oddly I guess. I'll see if I can borrow a mic but its just academic I suppose. It doesn't need a bore, I'm just swapping the heads but it was just something I hadn't seen before (being stamped only to hundredths rather than thousandths).
    Now I'll need to be a bit careful about the cam with that much compression. A set of World 2.02 heads and this thing should get the old wagon moving.
    Thanks again- Greg

    Isn't conforming to non-conformity still conforming?
  8. has to be 60 over....they definitely never made 90's
  9. mechanic58
    Joined: Mar 21, 2010
    Posts: 681


    Um...measure the bore. 4" is standard, if they're .060" over it'll be 4.060".

    Also - curious about what you meant by "bigger heads" Worst thing you could possibly do is put a set of large chamber heads on a 327. Might as well weld a hook to it at the same it'll be easier to use it for a boat anchor.
  10. rustang
    Joined: Sep 10, 2009
    Posts: 710


    Here is a picture of my 327 when I opened it up last year.... these are Badger P530's with .030 bore...

    I did keep the pistons in the engine, I did think long about it, and would/should have just went ahead with new does run on premium with my ignition really turned down... no-way, no-how will it run on regular......

    I'm thinking of tearing it down and pulling them out eventually...

    Attached Files:

    Deuces likes this.
  11. 58- Like I said, I'll have to borrow a mic to measure it. Also, as stated, the "bigger heads" are World Products with 2.02 valves. For some reason I think they'll flow better the the #882 smog heads w/ 1.94s that I pulled off. Chamber is the same 76 cc. Just bigger valves and better flowing ports. Perhaps I should have just said "better heads" but my ol lady gets suspicious when I start talking about getting better head..

    I'm not afraid of compression, I'm not gonna hog out the chambers or dumb it down with thick head gaskets. Its not my daily ride and good gas is what it will drink.
    Thanks again for the help.

    Isn't conforming to non-conformity still conforming?
  12. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    Speed Pro still makes these pistons, but for how long who knows. The factory never rated the CR of these pistons at no more than 11:1; usually it was 10.5:1. The differences were in the 62 or 64 CC chambers, and steel shim head gaskets. Speed Pro markets them as 10.35:1; the GM factory probably just rounded it off. to 10.5 or 11.0 even though they were somewhat less. 70 or 76 CC factory heads would get you down into regular gas territory, and lose some power in the process. I have 2 327's with these pistons, one is all new and has't been assembled; it still needs balancing. As far as any markings on the pistons, measure the bore, and piston itself if possible. Butch/56sedandelivery.
  13. mechanic58
    Joined: Mar 21, 2010
    Posts: 681


    You can get an idea if it's been bored or not just using a good tape or metal scale. If it's .060 over, thats just about a 1/16" of an inch. You can see that on a scale, you won't need a mic or a caliper to get a rough idea.

    That is if you can see that

    Mmm...if that motor had 882s on it, I bet it was sick as hell. lol Definitely not a good choice on a 327 and they just barely do ok on a 350. Remember the largest chamber GM used on any production 327 was only 64ccs. (advertised)
  14. So, I checked the bore and they are 4 and a sixteenth. Looks like badger did only stamp them as 06 (.060 over). Thanks for the advise guys. Greg

    Posted from my office while pretending to work!
  15. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    Last edited: May 4, 2020
  16. Budget36
    Joined: Nov 29, 2014
    Posts: 7,262


    You figured out how to measure an 1/8th inch;)
  17. Deuces
    Joined: Nov 3, 2009
    Posts: 21,311

    from Michigan

  18. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    No. Actually, I have two sets of these pistons hung on large journal rods. They look the same, but one set is for a 350, the other for a 327. The 327 set has a different part number, being made for Badger/Ohio/Perfect Circle by TRW/Speed Pro. I also have the forged 327 and 350 cranks. I'd gotten the numbers mixed up and cancelled the posting. May have a large journal, forged rotating assembly, for a 327, for cheap. I am Butch/56sedandelivery.
    Desoto291Hemi likes this.

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