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74 NovaMan's 1979 Chevy Truck - LS Swap - 5/6 Drop

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  • Originally posted by SuperBuickGuy View Post
    if you do forced induction, remember to increase the gap on your rings..... that would really bite to spend all that money then hang a ring and break a land....

    oh yeah, and buy the ARP bolts
    Thanks for the note on ring gap. I probably would have missed that. What are you planning for your gaps?

    The new rods come with ARP bolts.
    Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
    74 Nova Project
    66 Mustang GT Project

    92 Camaro RS Convertible Project
    79 Chevy Truck Project
    1956 Cadillac Project

    Comment


    • Originally posted by 74NovaMan View Post

      Thanks for the note on ring gap. I probably would have missed that. What are you planning for your gaps?

      The new rods come with ARP bolts.
      whatever Google tells me...
      Doing it all wrong since 1966

      Comment


      • Originally posted by SuperBuickGuy View Post

        whatever Google tells me...
        I see how you are! Making me do my own research!

        Seriously, I very much appreciate your input on all of this stuff even if I end up going another direction.
        Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
        74 Nova Project
        66 Mustang GT Project

        92 Camaro RS Convertible Project
        79 Chevy Truck Project
        1956 Cadillac Project

        Comment


        • The block checked out very well. I am going to go with the .005 over pistons and hone the cylinders to fit likely under $100 (vs $480 for boring oversize). My piston choices are 7cc dish: https://www.summitracing.com/parts/sum-2999273785-7 or 2cc dome: https://www.summitracing.com/parts/sum-2999273785-2

          If I use the 706 heads that I have (pressure tested good) my compression ratio is either 9.7 or 10.9 respectively.

          I have a line on 317 heads from a 2008 6.0L that were removed at under 10,000 miles from new that I can get for cheap. These would be ready to run but the chamber size is 71cc (vs 61cc for the 706 heads) Compression ratio for this head is either 8.7 or 9.6 respectively. This is according to the chart from Summit:

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          Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
          74 Nova Project
          66 Mustang GT Project

          92 Camaro RS Convertible Project
          79 Chevy Truck Project
          1956 Cadillac Project

          Comment


          • Here is an interesting article on stock head choices that would seem to indicate that the 706 head is a better choice when all else is equal (on an NA motor).

            http://www.superchevy.com/how-to/eng...nder-head-test

            Question for the gallery: Is a compression ratio of 10.9 too much for 87 octane for this motor? Is 9.7 a better target? It appears to me that the tuning available with the fuel injection and ignition that too high a compression ratio (as long as its not crazy) is less of a concern.
            Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
            74 Nova Project
            66 Mustang GT Project

            92 Camaro RS Convertible Project
            79 Chevy Truck Project
            1956 Cadillac Project

            Comment


            • I run 11 - 1 on the street in the wagon but not on 87 octane.
              I run 9.7 -1 on the street in the truck but not on 87 octane (it has cast iron heads).
              What is the truck's main purpose - you looking to kick some ass or are you going the thumper cam and flowmaster route?
              Those other heads sound like a good choice for a forced induction build so if that is probable then you might consider the best combination for the future.

              How much ignition lead do those LS engines like?

              Comment


              • Originally posted by 74NovaMan View Post

                I see how you are! Making me do my own research!

                Seriously, I very much appreciate your input on all of this stuff even if I end up going another direction.
                I'm not much into, when I don't know, googling then acting like a solid resource... If I know, I'll tell you, if I don't I won't (unless you're my wife and you ask the same thing twice... then I'll give you the same advice I give here which is "under any circumstance do not follow my second bit of advice - even if it were possible")

                Originally posted by 74NovaMan View Post
                Here is an interesting article on stock head choices that would seem to indicate that the 706 head is a better choice when all else is equal (on an NA motor).

                http://www.superchevy.com/how-to/eng...nder-head-test

                Question for the gallery: Is a compression ratio of 10.9 too much for 87 octane for this motor? Is 9.7 a better target? It appears to me that the tuning available with the fuel injection and ignition that too high a compression ratio (as long as its not crazy) is less of a concern.
                LS motors are a different animal - the same cubic inch compared to a gen 1 can live with much higher CR.... on swill, a gen 1 could run 10:1 with careful tuning. Yet the LS you can play at 11:1 without a fear. As with any motor, though, what a motor will tolerate requires a solid knowledge of the parameters (air flow, cam duration and timing, and how the fuel is put in - efi/port, etc).... the common rule back in gen 1 days was 7 or 8:1 compression on a boosted application, now? 9-10 is considered just fine.

                heads..... https://www.lsenginediy.com/ultimate...r-heads-guide/
                there's the numbers for each and every LS head.....the 317/243/799 all flow basically the same with the difference being the combustion chamber size

                and if you don't want to read down to see the flow works on the 5.3 head (despite the smaller valve)... here's this - say you send off any of those heads to a lingenfelter or such.... the same CNC program is used to port them, to me that speaks volumes about how similar they are (and how some trolls want you to believe their version is 'the best')....
                Last edited by SuperBuickGuy; January 6, 2020, 06:32 PM.
                Doing it all wrong since 1966

                Comment


                • I have not been paying attention what was the reason for the rebuild? Is it getting boost, or maybe some day?

                  Go with the small chamber heads.
                  ​​​​
                  https://youtu.be/gJCT5RvPCwM
                  http://www.bangshift.com/forum/forum...-consolidation

                  Comment


                  • Fuel rating... 350 small block, headers, intake, cam, big coil drives fine empty on regular fuel, but with loads, I find it likes premium better.. Lugs better, pulls better..empty less downshifting as well.. I might be running too much timing..

                    Comment


                    • Originally posted by cstmwgn View Post
                      I run 11 - 1 on the street in the wagon but not on 87 octane.
                      I run 9.7 -1 on the street in the truck but not on 87 octane (it has cast iron heads).
                      What is the truck's main purpose - you looking to kick some ass or are you going the thumper cam and flowmaster route?
                      Those other heads sound like a good choice for a forced induction build so if that is probable then you might consider the best combination for the future.

                      How much ignition lead do those LS engines like?
                      The trucks main purpose is summer daily driver. Before the rebuild rabbit hole I was planning in stabbing a moderately hotter cam in it and hoped for 400 hp with cam, intake, headers and tuning. The 87 octane requirement is self imposed because I believe that it will be easy enough to tune for that with the flexibility of the fuel and ignition controls. Mostly I'm tired of the ever increasing cost of premium gas over 87.

                      Now that I'm spending more with the rebuild, I'm looking to maximize the potential I guess. I should probably focus on building a sound 350-400 horse motor with the flexibility to turbo it later.
                      Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
                      74 Nova Project
                      66 Mustang GT Project

                      92 Camaro RS Convertible Project
                      79 Chevy Truck Project
                      1956 Cadillac Project

                      Comment


                      • Originally posted by SuperBuickGuy View Post
                        LS motors are a different animal - the same cubic inch compared to a gen 1 can live with much higher CR.... on swill, a gen 1 could run 10:1 with careful tuning. Yet the LS you can play at 11:1 without a fear. As with any motor, though, what a motor will tolerate requires a solid knowledge of the parameters (air flow, cam duration and timing, and how the fuel is put in - efi/port, etc).... the common rule back in gen 1 days was 7 or 8:1 compression on a boosted application, now? 9-10 is considered just fine.

                        heads..... https://www.lsenginediy.com/ultimate...r-heads-guide/
                        there's the numbers for each and every LS head.....the 317/243/799 all flow basically the same with the difference being the combustion chamber size

                        and if you don't want to read down to see the flow works on the 5.3 head (despite the smaller valve)... here's this - say you send off any of those heads to a lingenfelter or such.... the same CNC program is used to port them, to me that speaks volumes about how similar they are (and how some trolls want you to believe their version is 'the best')....
                        Good insight as always. Thanks again. The reading I've done so far backs up your statement above. The more I look into the different heads, the more it appears that there is very little difference at the power levels I'm contemplating (given i have this cam in hand: https://www.summitracing.com/parts/nal-12638427) and that the combustion chamber size is probably the most critical detail.
                        Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
                        74 Nova Project
                        66 Mustang GT Project

                        92 Camaro RS Convertible Project
                        79 Chevy Truck Project
                        1956 Cadillac Project

                        Comment


                        • Originally posted by Russell View Post
                          I have not been paying attention what was the reason for the rebuild? Is it getting boost, or maybe some day?

                          Go with the small chamber heads.
                          ​​​​
                          https://youtu.be/gJCT5RvPCwM
                          I was planning on a cam swap and found some milkshake in a corner of the passenger side head. So far we have not found a source for that as the head pressure tested fine. It may have been a head gasket issue. Teardown revealed the need for new pistons and it's snowballing from there. I'd like to leave the option of boost open since I'm so far in anyway.
                          Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
                          74 Nova Project
                          66 Mustang GT Project

                          92 Camaro RS Convertible Project
                          79 Chevy Truck Project
                          1956 Cadillac Project

                          Comment


                          • Well I finally laid eyes on the other set of heads. They are 823 castings and very nice pieces. From the link SBG provided above:

                            "LS7 Heads - These were the first heads to bring race car quality and technology to the OEM side. Although common in the aftermarket, CNC-porting of the intake and exhaust runners is usually too costly for a factory head. Titanium intake valves and sodium-filled exhaust valves were previously unheard of in a domestic factory engine, which revved to 7,200 rpm, another anomaly for a pushrod V-8. Right out of the box, these heads have supported more than 600 hp naturally aspirated and substantially more with forced induction. The large, raised runners and 12-degree valve angle enable substantial flow that supports large cubic inches ... the large valves necessitate a 4.125-inch or larger bore"

                            In addition to being rectangle port intake heads (the intake I have is for cathedral port) the 4.125 inch bore requirement will not work on a 5.3.

                            So we are using the 706 heads and our compression choices are 9.7 or 10.9. 10.9 seems a bit much and will be kind of on the edge for boost for me. 9.7 is the winner.
                            Chris - HRPT Long Haul 03, 04, 05, 13, 14, 15,16 & 18
                            74 Nova Project
                            66 Mustang GT Project

                            92 Camaro RS Convertible Project
                            79 Chevy Truck Project
                            1956 Cadillac Project

                            Comment


                            • same decision path as I made... 10.9 is fine if you're not going to boost it, heck you could boost it, however 9.7 lets you run swill
                              Doing it all wrong since 1966

                              Comment


                              • And there is lots of swill available out there.
                                Ed, Mary, & 'Earl'
                                HRPT LongHaulers, 08, 09, 10, 11, 12, 13, 15, 16, 17, 18, 19.


                                Inside every old person is a young person wondering, "what the hell happened?"

                                The man at the top of the mountain didn't fall there. -Vince Lombardi

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