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  • 350 SBC done

    Finally finished the "poor man" rebuild of the 350 SBC in the Corvette. Nice to have it fire right up last night after being in various states of disassembly for 18 months.

    The original 48 year old timing chain was so stretched and the nylon inserts gone missing to the bottom of the pan that I had to reposition the distributor about an inch more rotation from where it was before just to get the ignition timing close enough to fire while doing the first crank.

    The 1969 dated 55k mile 4-bolt block kept the flattop 4 eyebrow pistons, crankshaft, rods and the .390/.410 camshaft. All else changed.
    • high volume oil pump
    • double row timing chain
    • hi-torque mini starter
    • 58cc '128' aluminum heads, .015" head gasket
    • 1.52 intake/1.6 exhaust rockers
    • head studs
    • aluminum water pump
    • '79 aluminum intake manifold
    • '81 tubular exhaust manifolds


    By my scale I took 122 lbs off the front of the car from the original all cast iron state. Still breaking in the new lifters but I am expecting about 290-310 hp to the rear wheels with 400 ft lbs (~11:1 CR). With the fresh bearings and high volume oil pump I am at 78 psi using 30W break in oil. I may have to run 5W-30 from now on from the 10W-40/20W-50 I was using.
    Last edited by Dynra Rockets; 02-14-2017, 11:11 AM.
    92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

  • #2
    Its crazy how much weight can be shaved out of those things with some aluminum components. Sounds like a nice setup. Stock carb?
    The only thing that oughta be hella flushed is a toilet.
    http://www.miataramblings.blogspot.com

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    • #3
      Stock carb?
      Almost, for break in I am using the Holley spreadbore that I was previously running. Once everything checks out I am converting to FiTech fuel injection.
      92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

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      • #4
        Nice. I've been trying to talk my dad into fuel injection for his '79.
        The only thing that oughta be hella flushed is a toilet.
        http://www.miataramblings.blogspot.com

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        • #5
          Solid or roller lifters?

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          • #6
            Originally posted by 91LudeSiT View Post
            Solid or roller lifters?
            Neither. old school hydraulic flat tappet
            Last edited by Dynra Rockets; 02-14-2017, 04:00 PM.
            92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

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            • #7
              Amsoil zrod for you then.

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              • #8
                With your high volume oil pump, did you get a HP Canton oil pump shaft, as the stock shaft will twist over time due to the higher volume and great pressure on the shaft. Go ahead, ask how I know

                Bill S.
                Instead of being part of the problem, why not be a part of a successful solution

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                • #9
                  Originally posted by mrbill View Post
                  With your high volume oil pump, did you get a HP Canton oil pump shaft, as the stock shaft will twist over time due to the higher volume and great pressure on the shaft. Go ahead, ask how I know

                  Bill S.
                  I looked into it but when I compared the 1969 shaft to another I had from a 80's vintage engine the 69 was slightly larger in diameter and the metallurgy seemed much better. I decided to keep it (keeping with the "poor man" rebuild after all ). As stated I will likely need to run thinner oil than I have traditionally used to get the pressure down to normal level. This is just a street car cruiser and will never see a track or likely above 4800 rpm. Time will tell though.

                  I have had a lot of people ask me on other forums why I didn't change out the cam. The OEM 300 hp cam that was in there is an adequate street cam (for a 2990# car) and since I do not plan to run higher rpms the torque level is right about where I want it. I have no desire for a lopey idle quality for this car either.
                  Last edited by Dynra Rockets; 02-15-2017, 09:28 AM.
                  92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

                  Comment


                  • #10
                    Originally posted by Dynra Rockets View Post
                    Almost, for break in I am using the Holley spreadbore that I was previously running. Once everything checks out I am converting to FiTech fuel injection.
                    You'd be better off with a carb. Those are very bad TBIs and result in incredibly poor fuel distribution.
                    DIYAutoTune.com

                    | 10AE-T | BEGi S4 | GT2560r | Enthuza | 6UL | MS3Pro PNP|
                    | 2001 Track Rat | Enthuza | Jenvey | MS3Pro PNP | Exocet in Progress|
                    | 1992 323 | Wrong-wheel-drive Miata Endurance Racecar|

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                    • #11
                      Originally posted by ben91 View Post
                      You'd be better off with a carb. Those are very bad TBIs and result in incredibly poor fuel distribution.

                      First I heard of that. The only negative reviews I have read about poor running were in engines with big cams. 99.9% of the reviews I read were very positive. Again, my use case is just a cruiser so easy starting, good drivability manners, and less unburned fuel in the exhaust are my primary criteria.

                      NOTE: I am using the Go-StreetEFI carb replacement and not their port injection as used on LSx engines.
                      Last edited by Dynra Rockets; 02-15-2017, 09:22 AM.
                      92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

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                      • #12
                        I'm aware of the product. Have tested that several other similar TBIs. You'll hate it. I'd keep the carb or go to port injection. Or even an old school GM TBI would work better.
                        DIYAutoTune.com

                        | 10AE-T | BEGi S4 | GT2560r | Enthuza | 6UL | MS3Pro PNP|
                        | 2001 Track Rat | Enthuza | Jenvey | MS3Pro PNP | Exocet in Progress|
                        | 1992 323 | Wrong-wheel-drive Miata Endurance Racecar|

                        Comment


                        • #13
                          After the 3.4L V8 goes in the Italia then next up will be the T5 in the Corvette along with a C4 rear suspension and differential. It might be close to 2900# by then.
                          92 Italia "Competizione Speciale". 91 BRG, '69 Corvette "Mojo". '14 F150 Coyote 5.0. Looking for something blue.

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