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  • Engine: safely bore a 289

    How much can a 289 be safely bored? Does it depend on year of manufacture? Was the 304 a bored out 289 or a different block? I apologize if this has been discussed (I'm sure it has) before.
    Toby Knoll Garage

    www.tobyknollgarage.com
    ______

    '51 Muntz Jet
    '53 Woodill Wildfire/Dodge
    '54 Hudson Hornet Grand National Tribute car
    '55 Studebaker Speedster/Cadillac
    '56 Corvette SR replica


  • #2
    I have had several done to 0.060" over (successfully). At that much or more, it depends on the block that you are starting with. They are not all the same.
    Gary L.
    Wappinger, NY

    SDC member since 1968
    Studebaker enthusiast much longer

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    • #3
      It's easy...have the block "sonic checked". Any good machine shop should be able to do this for you for a reasonable cost.
      I bought a checker to check cylinder heads when I port them. Not all casting are the same, EVEN the same casting number will have different wall thicknesses..!

      That's the ONLY...way that you'll know how far your (or any) block can be safely overbored..! AND...are you going to be running just a carburetor, or a blower (boost pressure?) or nitrous ? You can squeak by with less thickness with a naturally aspirated vs. a blower or nitrous oxide.

      Mike

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      • #4
        Like Mike posted. Sonic check. Move boring bar to the middle of the casting. I'm running one bored .187 to 3 3/4 making it a 320 ci. It sure makes a torque. Engine is in a 64 Champ 3/4 ton. It also has a R1 cam. Used 305 GM pistons.
        Last edited by DieselJim; 07-06-2021, 05:31 PM.

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        • #5
          Agree'd. Sonic testing does give you good info.
          Being systematic in your test methodology helps, too.
          Here's a method used testing a block.
          Sonic test was done in a clock pattern and at every inch down the cylinder.
          An Excel file was made to record the numbers and then a spider chart was created to visualize the results.
          What we have found (depending on year) is there are some thinner spots on the 12 o'clock middle on #3/5 and #4/6.
          A thinner spot on the oil drainback hole area on #7.
          T thinner spot on #8 low (full flow near 6 0'clock, by the oil filter casting boss).
          This is not a general comment, but what has been found on specific blocks.
          The only way you will really know is to test.


          Click image for larger version

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          HTIH (Hope The Info Helps)

          Jeff


          Get your facts first, and then you can distort them as much as you please. Mark Twain



          Note: SDC# 070190 (and earlier...)

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          • #6
            Good info from all above.

            Yes, all Studebaker V8 blocks from 1955-'64 are basically the same. Some here have their favorites; the '55 blocks are the best. Some feel the full-flow blocks have thin areas in the area of the filter boss.

            We've bored about as many as any and .093" (the R3 bore) is usually safe; but not always. We're dealing with seventy-five-year-old blocks with unknown provenance. I had one have a hole appear at .060". Guess was a casting inclusion which rusted through from the inside.

            We've bored several +.117" oversize, giving 308". I know some who've bored to 3.75" (+.1875")

            Bottom line - any big bore project block should be sonic tested. Even then, it's impossible to hit every possible flaw.

            jack vines

            BTW - have the pistons in hand before boring the block. There are no readily available pistons beyond .060". Custom machine work and/or custom forged pistons are necessary to get more than 299".

            jv
            Last edited by PackardV8; 07-06-2021, 05:54 AM.
            PackardV8

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            • #7
              I had a stock 1963 259 bored .030 and a hole appeared in one cylinder, so it had to be over-bored and have a sleeve inserted.
              sigpic
              In the middle of MinneSTUDEa.

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              • #8
                The 289 CID I am working on went out 117 thou in order to fit lighter late model pistons and low drag ultra thin rings. Make sure your block is sonic tested in order to ascertain it's integrity. This yielded 308 CID. I also have one I did many moons ago and it was .093 over in order to end up with an R4 clone of 304.5 CID. That bore to stroke ratio created an awesome incredibly high RPM performance unit making a ton of power(there were many other modifications to the heads etc.). Maybe I just got lucky with the blocks but they are full flow oilers.

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                • #9
                  I wish someone had sonic tested the Champion six engine I bought.

                  It was rebuilt and for sale at an International meet in Las Vegas around 1989-1990. I put it into a 51 Champion and it lasted about 30 miles before losing power. Taking out the spark plugs and looking down the spark plug holes, a friend cranked the car and a geyser of water knocked me a$$ over teakettle off the car and onto the ground.

                  It must have been funny to any onlookers.

                  Pulling the head revealed a kidney bean shaped hole half way down the number two cylinder wall.

                  The engine must have been bored into a weak spot or void in the casting.
                  RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

                  17A-S2 - 50 Commander convertible
                  10G-C1 - 51 Champion starlight coupe
                  10G-Q4 - 51 Champion business coupe
                  4H-K5 - 53 Commander starliner hardtop
                  5H-D5 - 54 Commander Conestoga wagon
                  56B-D4 - 56 Commander station wagon
                  60V-L6 - 60 Lark convertible

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                  • #10
                    Originally posted by RadioRoy View Post
                    Pulling the head revealed a kidney bean shaped hole half way down the number two cylinder wall. The engine must have been bored into a weak spot or void in the casting.
                    A seventy-year-old casting which was run with who-knows-what in the cooling system and/or left out in the weather for who-knows-how-long?

                    We were sent the engine from the first 1955 Packard Caribbean. The coolant passages were filled with the worst crud ever; probably some or several kind(s) of patented stop-leak. It took two days of manually rodding out the crud and three pressure washings to get it clean enough to begin machining. Then, the two rear cylinders had holes show up at .060"; the Packard blocks are always good for .125". The owner wanted to preserve the original block, so we sleeved the two rear cylinders.

                    But yes, Roy, that's always the engine builder's nightmare; a hidden flaw just under the freshly honed cylinder wall which can't be seen but will blow out once the cooling system gets up to pressure.

                    jack vines

                    PackardV8

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                    • #11
                      I notice that SI lists 289 & R1/R2 pistons in 0.080 oversize. This results in 302.2 C.I. It seems to me that Studebaker, in 1962, should have bored out all the R1 & R2 engines 0.080" to 302 C.I. if for no other reason than marketing. This would have separated the R1 & R2 from the garden variety 289s, plus 302 sounds much better than 289. The US auto industry was in a cubic-inch (& HP) race then and Studebaker was being left behind.

                      -Dwight

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                      • #12
                        My question is somewhat in the same direction.

                        How big can a person bore a studebaker block if they were to use all custom wet sleeves? (Theoretically)

                        I wonder about this from time to time.
                        10” tall deck, 4-1/2” bore spacing. . . Seems like someone should be able to get quite a few cubic inches out of a studebaker.

                        This leads me to wonder upon the heads which already flow pretty poorly. One would have to put R3 heads on a custom sleeved block just for it to have a chance.

                        eventually I conclude that it would have been WAY cooler for studebaker to use the Packard V8 as their big block. I can only imagine how cool it would have been to have a Paxton charged Packard as an option in the Avanti when it first came out.

                        Dwight, I like the way you think. That would have been pretty cool. One problem I see is that a lot of the masses already think that studebaker used Ford motors. Can you imagine how much worse that headache would be if studebaker had a 289 and a 302?

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                        • #13
                          Originally posted by thehotrodder View Post
                          My question is somewhat in the same direction.

                          How big can a person bore a studebaker block if they were to use all custom wet sleeves? (Theoretically)

                          I wonder about this from time to time.
                          10” tall deck, 4-1/2” bore spacing. . . Seems like someone should be able to get quite a few cubic inches out of a studebaker.
                          Been discussed many times. The basic block architecture would easily go 400".


                          This leads me to wonder upon the heads which already flow pretty poorly. One would have to put R3 heads on a custom sleeved block just for it to have a chance.
                          Again, been discussed many times. Studebaker Engineering was at work on a 340" version for which the R3 heads would have been used.

                          eventually I conclude that it would have been WAY cooler for studebaker to use the Packard V8 as their big block. I can only imagine how cool it would have been to have a Paxton charged Packard as an option in the Avanti when it first came out.
                          Yes, way cool. I've always felt S-P should have offered the Packard V8 in premium cars and the trucks.

                          No, couldn't have happened. By the time the dust settled after the merger, S-P Board of Directors were already planning an exit from car and truck manufacturing. The Packard engine line shut down mid-'56.

                          Maybe, dreams are what this hobby is all about.

                          jack vines, who has a Packard Caribbean V8 in his '55 E12.
                          PackardV8

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                          • #14
                            Originally posted by thehotrodder View Post

                            I can only imagine how cool it would have been to have a Paxton charged Packard as an option in the Avanti when it first came out.
                            Not an Avanti, but a good friend just bought a complete McCulloch supercharger setup that he plans to install onto his ‘56 Golden Hawk with overdrive. Cool doesn’t begin to describe it. I told him he better plan on leaving the hood off.

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                            • #15
                              While still employed by the Ar Nat Guard in the 90's i was teaching my self to use the shop's boring bar. a junk 259 full flow block was bored 'till their was no cylinder left. then it dawned on me' whats going to hold the deck to the crankcase. wet sleeves wont do it! health issues retired me and the block went to scrap, but the question still remains!!! Luck Doofus

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