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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi 615 SR20 or 632 12 DegreeGo | New | Find | Notify | Tools | Reply | |
| 615 SR20 or 632 12 Degree | Login/Join |
| DRR S/Pro |
that sounds about right, an aluminum tall deck block is about 130 pounds lighter then a iron aftermarket block.... which is exactly what you gained .991 60' 4.36 @ 159 so far..... 6.86 @ 198 trying for more...... 533" single carb 235" Harrison 4-link | |||
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| DRR S/Pro |
Dollar for dollar, I would rather build a aluminum SR20 618, I believe it would be a more competitive combination. That weight difference (aluminum block over an iron block) verses the power increase of the 12 degree combination is the game changer for me. Just my two cent opinion. Bob | |||
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| DRR S/Pro |
So I weighed my 12 degree stuff since its apart right now. Manifold is 19 pounds with carb studs Heads are 38 pounds bare each Valves are 4 pounds, all 16 Rocker stands are 10 pounds with all bolts and shims Rockers are 5 pounds all 16 Pushrods are 3 pounds Valve springs w/ retainers 4 pounds Valve covers 4 pounds For a grand total of 125 pounds... I don't see a whole lot of room for taking a bunch of weight off the car there .991 60' 4.36 @ 159 so far..... 6.86 @ 198 trying for more...... 533" single carb 235" Harrison 4-link | |||
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| DRR Sportsman |
the weight is not saved from the heads themselves so much as much as it is from the configuration of the entire motor from 618 to 632 | |||
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| DRR Sportsman |
a 598 SR 20 is also lighter than a 618 SR20 due to moving to a tall deck block on the 618 or 632 | |||
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| DRR Trophy |
I have built both. Your speadport stuff will always out mph the SR20 stuff. As far as reliability the SR20 stuff is pretty good. | |||
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| DRR Elite |
 As I stated in the first reply to this thread. | |||
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| DRR S/Pro |
spanky. Always is a dangerous word. And spread port is not specific enough also. | |||
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DRR Sportsman |
Why not a 632 SR20 ? 17 cubes at 2hp per cube,every little bit helps. Working for the Weekend!!!! Fordyce Motorsports | |||
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| DRR Pro |
Weight for one... | |||
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DRR S/Pro |
Ed, Our 615 SR20 motor ran 191 in SC trim at 1940lbs so it can be done, but that was with a cam that was almost 1" of lift and hard on valve train. If I wanted to go fast in SC I would do the 12 degree myself. Keeping the Socialists and NEO-LIBERALS at bay with FACTS one post at a time !!! Freedom isn't free !!! Thank a veteran, they will actually appreciate it. | |||
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| DRR Sportsman |
I dont think anyone should disagree that the 12* is going to out mph the SR20 in an apples to apples situation | |||
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| DRR Elite |
that's what the OP asked. That said, in my opinion the OP should be more concerned with his choice of engine builder for either of these costly and high HP engines. A Professional engine builder who has built hundreds of these engines, proven in the dyno room and more importantly on the track, will produce more reliable power and therefore highest MPH than the guy that does a few engines for friends. Further, I am not aware of one super comp racer, currently competing in NHRA Division 1 running either of these engines built by the OP's builder. | |||
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| DRR Trophy |
Thank you very much for all your input it has been very helpful. My engine builder works for a large well established race engine builder but builds my engines on the side. I totally agree with you that you need to have an established builder build one these. | |||
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DRR S/Pro |
Build a mild conventional head 565, put a small blower on it, enjoy the low maintenance and run big mph. My 2¢ 272" Spitzer 540 Chevy The Blower Shop XR1 FTI XPM Series Converter FTI Level 6 Powerglide 3.69@199 .916 60' 2017 Bradenton Heads Up Madness Open Outlaw Champ 2018 PDRA T/D #5 2019 PDRA T/D #2 2020 Retired From T/D Competition.... 2020 Bradenton NMCA Hemi Shootout Winner 2021 getting back into bracket racing with a Gen3 Hemi powered 87 Cutlass. | |||
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| DRR Sportsman |
Hey Tony, good luck with the new combo.....whichever you choose. FWIW, I love my SR20, but apples to apples you will get a little more speed out of the 9-12* stuff. The weight is something to consider too. I've been just shy of 185 @ 1950 #'s. Give me a shout if you have any questions. Shawn | |||
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| DRR Elite |
No surprise, MightyBirdF145...KNOWS! | |||
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| DRR S/Pro |
Shawn and Ed We all know stop MPH is as much about HP and the T Stop set up! Both contribute to finish line MPH. What will high mph t stop setup loose vs all out, 2, 3 mph ??? My combo adjusted to Shawn's weight would MPH between 192.5 to 193.5 all out so I'd guess a high mph t stop setup would run 190 on my Pro 20 632 adjusted to Shawn's weight. Also your typical 9 or newer 12 degree (older profiler's need some help) combo's should make more steam than the SR20/Pro20 combo's but the lose of 25 pounds does basically equal out on track performance or dam close. The older 18 degree stuff will be slower than the SR/PRO 20 combos also! This is what I have seen with all the combo's as noted above that I know what's is in these types of engines which allows me to put them in and apples to apples comparison.This message has been edited. Last edited by: TOP38, | |||
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| DRR Trophy |
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| DRR S/Pro |
How much does rear gear play a factor in this? | |||
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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi 615 SR20 or 632 12 Degree
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