Thinking out loud... MSD LS7 vs FAST LS3 Med Runner - LS1TECH - Camaro and Firebird Forum Discussion

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Thinking out loud... MSD LS7 vs FAST LS3 Med Runner

 
Old 02-06-2019, 04:13 PM
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Default Thinking out loud... MSD LS7 vs FAST LS3 Med Runner

Yeah, yeah, weird I know.

But let's say you have a 416 with a 4.070" bore and can run either a 255/260 LS3 head or a 265 small bore LS7.

The MSD is a long runner intake and will make more torque but it seems to force most LS7s to peak in the 6300 range give or take a little bit. Now they do hold on pretty well, usually past 7K with enough cam and ported LS7 heads on a larger motor with more bore. And it's definitely capable of supporting upwards of 660-670rwhp with enough motor behind it. It makes me think it might make better avg power 4000-6000 and still peak higher and hold to 7500.

But with Hammer's car, we've seen an LS3, when spun high enough, can make that power with a FAST LS3.

For a 416 with a target of 7500 RPM, would the 265/LS7/MSD combo work? I know it'd give more avg power but is it going to be down from say 5700-7500 to the LS3/FAST combo?

The other option I've looked at (and you'll see my other post) is the TSP LS3 Sheetmetal intake. I know it'll outpower both the FAST and the MSD at 6000+RPM. But as a street car, losing 40-50ft-lbs in the 4000-5500 range might be a little too hard to swallow... So trying to figure out if anyone had any sort of evidence on this comparison. I haven't seen anything.
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Old 02-06-2019, 05:27 PM
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If you have the cubic inch and the compression ratio plus cam events, youre not as inclined to need a longer runner.

Avg torque would win out vs max peak hp in nearly any race, but solid roller would help in both depts.

Solid roller and 7800-8k on ls3 heads and tsp intake would be my bet. That would kill on the track. Street...id stick with a FAST.

I havent seen real definitive proof of gains from a real unported fast to a ported only. Tsp did set and break the ls3 sbe record multiple times with a stock out of the box fast tho.

Maybe once i get these dang engines done, i can focus more on that. The biased dynos and unrealistic builds give no good info at all and too many builds change too much to make them worth while in comparison.
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Old 02-06-2019, 05:32 PM
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The FAST out of the box works well. I know the MSD is stronger on the LS7 but the short runner FAST changes the dynamic a bit.

But that TSP intake would be faster at the track.

Of course I have a big stall too. So torque matters less.
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Old 02-06-2019, 05:38 PM
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Avg torque would still matter even above 5000. Thats why tsp had so many dyno runs on their recent sbe ls3. Peak hp is great, but when you can pair that with the tq also, lights out.

I really dont like the msd design. It performs, but you're limited to cathedral or ls7 port. The short runner fast and add porting on top would be killer also.
Tsp used the std long runner.
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Old 02-06-2019, 11:34 PM
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Originally Posted by JakeFusion View Post
..But let's say you have a 416 with a 4.070" bore and can run either a 255/260 LS3 head or a 265 small bore LS7......a street car......
Speaking for me.....if I had to do over again, I'd do the small bore LS7 and the MSD.

KW
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Old 02-07-2019, 02:08 AM
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Originally Posted by KW Baraka View Post
Speaking for me.....if I had to do over again, I'd do the small bore LS7 and the MSD.

KW
Are you running the FAST now?
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Old 02-07-2019, 02:00 PM
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Jake, have you been to Camaro5.com and read about GPI Max Performance Package?
They have stock displacement LS3's with over 500rwhp with their small bore LS7 heads heads that are 12 degrees, a MSD intake, and their cam. They are going to 7500-8000RPM.
There is a guy over there with 416, 12.5 compression, E85, and stick with 571rwhp.
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Old 02-07-2019, 02:31 PM
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I have not seen that package. But I had looked at GPI for their ported LS3 intakes and such. But that's interesting. The MSD should carry out further on a smaller motor...

Still seems to carry decently on the 416 with a 242/257 113+3 cam.


Last edited by JakeFusion; 02-07-2019 at 02:41 PM.
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Old 02-07-2019, 08:45 PM
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Tsp has ls3 guys above 500 to 550rwhp with f35, 260cc heads and holley hi ram. quite a few with the fast and maybe msd also.
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Old 02-07-2019, 09:58 PM
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We just put a gpi ss4 and their 281cc heads on my buddy's ls3 vette. Should have some results here shortly both dyno and track. It made 470whp with bolt ons so hopefully it will make it to the 550ish area. He has a mid runner fast for it.

The abundance of intakes make the ls3 style head a popular choice for sure.
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Old 02-07-2019, 10:15 PM
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TSP 376 stock cubed Ls3
TSP small bore Ls7's 12.5 comp - Holley High Ram 8900 thru the traps peak rpm 8500. SR cam...8 sec pass.
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Old 02-07-2019, 11:23 PM
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I would love to read more builds about PRC LS7 265cc small bore heads. I just don't see any.
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Old 02-08-2019, 12:58 AM
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Talked to a buddy @ tsp for the info... Nothin special, later the stock short block blew up, all on FB. If you would like to know more think of this with tsp Ls7 heads and Holley high ram. Wonder how well the CiD intake would do for mph & et? The TSP build is Very similar trust me.


https://www.yellowbullet.com/forum/s....php?t=1250106
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Old 02-08-2019, 01:12 AM
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Tsp ls7 265 small bore head 430cid Holley High Ram intake.

https://ls1tech.com/forums/dynamomet...o-results.html
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Old 02-11-2019, 04:48 PM
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Originally Posted by JakeFusion View Post
Are you running the FAST now?
Yes.....FAST LS3 w/Mid-length runners and AFR LS3 heads.

KW
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Old 02-11-2019, 06:01 PM
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Great... lol.

I picked up a medium runner FAST...
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Old 02-12-2019, 03:45 PM
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Originally Posted by KW Baraka View Post
Speaking for me.....if I had to do over again, I'd do the small bore LS7 and the MSD.

KW
KW did you ever post results or graph for your 429" AFR,LLSR W/Mid Length Runner FAST?
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Old 02-12-2019, 03:54 PM
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I picked up 4+ mph with a low profile Holley sniper over the fast mid runner. But I’m also shifting at 8000 now.

Up to 7500 I’d use the fast and closer to 8000 I’d use the sniper
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Old 02-12-2019, 09:29 PM
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Originally Posted by NAVYBLUE210 View Post
KW did you ever post results or graph for your 429" AFR,LLSR W/Mid Length Runner FAST?
No.....we tweaked the tune on the street but haven't put it on the rollers, yet.

Car is stronger than previous setup (from 4000 RPMs on up), despite the cam being a bit mild and the compression being a bit less.

April/May I plan to make it down to Pat G. for a full-on tune.

KW
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Old 02-13-2019, 03:18 AM
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Im going to put the sniper low rise on the 333 im building shooting for 7500ish. depends on if the heads will cooperate of course. Literally testing the limits of the stock 243 port with the rocker boss cut and the chamber milled quite a bit.
If i had more budget and an engine dyno i might test the reg ls3 head also and prob a short runner fast. the 250ish cc runner would be pretty great on a higher rpm short stroke setup like that. maybe i can get some more time on this engine and work at it. would be interesting right?
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