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Thread: 2bolt to 4 bolt conversion

  1. #11
    GofastRacer
    I agree caps braking is a rarety, they just walk around and cause problems. But if you're in the poor house(like me), you start out with an EARLY thick wall 2 bolt and add the splayed caps for serious shit. For a naturally aspirated 500 to 600 hp motor, 2 bolt dealios work fine with studs!. I agree though on the reasale, it is harder to sell a 2 bolt motor!..

  2. #12
    Fiat48
    GofastRacer:
    I agree caps braking is a rarety, they just walk around and cause problems. But if you're in the poor house(like me), you start out with an EARLY thick wall 2 bolt and add the splayed caps for serious shit. For a naturally aspirated 500 to 600 hp motor, 2 bolt dealios work fine with studs!. I agree though on the reasale, it is harder to sell a 2 bolt motor!.. For years the parts I have run have been used or from swap meets. I ran tall decks because they were all 4 bolt mains and could be had for $400 or less. But my thinking has changed the last few years. By the time you buy an old used block plus fully prep the block (line hone, boring, decking, etc), you got close to $1,000 in it. That's your foundation. All your high dollar stuff is rotating in this "cast just strong enough to make the warranty period" block. But with all the nice aftermarket blocks available for $2000.00 or less, I've gone to the aftermarket blocks. They have stronger main webs, pinned main caps, superior oiling systems and allow bigger bores for more compression with flatter domes. And a guy might be able to pick up one of these used and save some $$$ as more of them get out there.
    With blown alcohol I have walked the caps on every GM block I ever had, studs, or not. I don't know about the P&S Block in the Fiat or the Dart block in the boat as I haven't looked at them yet. But I suspect they will be better.

  3. #13
    OMEGA_BUBBLE_JET
    I wonder why people are all under the assumption that they need a 4 bolt main. My guess is they rely too much on what they read in some magazine article and don't do enough talking to people at the track or the machine shop. I get so tired of "Oh I read in a magazine it has to be true". there is a reason those guys are writing magazine articles and not out there winning races. Always have ran 2 bolts always will. I've heard people blame spinning a bearing on a 2 bolt block but sorry it is a machining problem or an oiling problem. So a message for all the "***boater's" out there. If you are investing in 4 bolt mains you might as well be burning money. If an engine builder is telling you you need 4 bolt mains he's screwing you.
    Omega

  4. #14
    TIMINATOR
    A two bolt block is fine up to about 550-600 hp, if you don't detonate it with too much timing or crap gas,BUT ONLY if the caps fit tightly in the registers,and the line hone is done by someone competent! USE STUDS!if you are making any H.P.! I would rather see a two bolt block machined correctly by someone competent,with studs, than any 4 bolt block prepped by a hack. Make sure that your machinist is a boater, a drag car guy may be proud that his motors run 100 10second passes just fine,thats only 16 minutes of making H.P.! I do that every weekend,you probably do too! P.S Truck blocks(tall deck) are great! Thick cylinders,ability to use long rods(great for jet boats)and strokers and usually cheaper than 4 bolt car blocks.

  5. #15
    Bow Tie Omega
    Amen to that Omega. Hot Rod Magazine does not cover it all, no matter what some think. Just talk to any real racer or builder and they will get a nice chuckle when asked about good ole Hot Rod Magazine. Hot Rod is good at covering the basics, but like you said, anything serious, talk to someone who knows.

  6. #16
    78Eliminator
    When you have cap walk, how can you tell by inspecting the bearings if you catch it before failure?

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