447 stroker on the way!
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Joined: Feb 2018
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From: Lawrenceburg Ky
421 had a 9 easy. Super vic 4500 and a decent solid roller to about 7300... tq is hp. Best wishes on your new thought.
My builder said he's gave me a lil extra room besides typical race tolerance for P to V clearances with flycutting. As this my interpretation of a street engine ver.1 another head package awaits.
-5cc flat top piston( valve pockets for ls 3&7 heads) 62cc milled FED ls3 stg1 heads with 735 inches of lift. Zach said he can get the valves to clean the pistons of carbon..lol.
My builder said he's gave me a lil extra room besides typical race tolerance for P to V clearances with flycutting. As this my interpretation of a street engine ver.1 another head package awaits.
-5cc flat top piston( valve pockets for ls 3&7 heads) 62cc milled FED ls3 stg1 heads with 735 inches of lift. Zach said he can get the valves to clean the pistons of carbon..lol.
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Sounds like Flyin with his 402 and 13.1 comp and hyd. roller. Made around 706hp and a low 9 second pass Told him a solid roller would be good for a 8 second pass and 800 hp. Swap and it was a 8 second pass and 800 hp below 8k. Now this was with Chris Frank factory stg 1 ported heads. No matter how you cut it a 102 thru 110 mm tb isn't better than a 4500. Just something to ponder.
With my own junk, if i'm not at or above 750...... 750 was a goal with 11.8 compression same engine. Now we're at 13.2
With my own junk, if i'm not at or above 750...... 750 was a goal with 11.8 compression same engine. Now we're at 13.2
Last edited by Smokey B; Jul 7, 2019 at 06:41 PM.
Thread Starter
TECH Regular
Joined: Feb 2018
Posts: 426
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From: Lawrenceburg Ky
Sounds like Flyin with his 402 and 13.1 comp and hyd. roller. Made around 706hp and a low 9 second pass Told him a solid roller would be good for a 8 second pass and 800 hp. Swap and it was a 8 second pass and 800 hp below 8k. Now this was with Chris Frank factory stg 1 ported heads. No matter how you cut it a 102 thru 110 mm tb isn't better than a 4500. Just something to ponder.
With my own junk, if i'm not at or above 750...... 750 was a goal with 11.8 compression same engine. Now we're at 13.2
With my own junk, if i'm not at or above 750...... 750 was a goal with 11.8 compression same engine. Now we're at 13.2
Originally Posted by Tuskyz28
Ive heard otherwise from Steve @ R.E.D..... he told me the factory number 7 sleeve is known to to crack and that he fixes 3 or more monthly.
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From: Mississippi
This is a topic worth discussing imo. So strange that the #7 cylinder is lost very often, and in fact it is. I spend a decent amount of time over on Corvette Forum, or at least I used to before the engine guys left over there, and it seems like dozens of folks were losing #7. Steve @ RED told me same as tusky. Perhaps a front mounted TB plays into this issue? Thoughts?
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Joined: Sep 2014
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From: Mississippi
This is a topic worth discussing imo. So strange that the #7 cylinder is lost very often, and in fact it is. I spend a decent amount of time over on Corvette Forum, or at least I used to before the engine guys left over there, and it seems like dozens of folks were losingg #7. Steve @ RED told me same as tusky. Perhaps a front mounted TB plays into this issue? Thoughts?
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It's the steam port setup... #7 runs leaner and hotter compared to the other cylinders. Put your fattest injector on it (if flow-matched or flow-benched) and run an aftermarket steam port setup. Otherwise, the way air is distributed with a plastic manifold, #7 leans out more than the others. The fix is a carb style intake... or the injector/steam port method. This has been known for a good decade or so?
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From: Mississippi
It's the steam port setup... #7 runs leaner and hotter compared to the other cylinders. Put your fattest injector on it (if flow-matched or flow-benched) and run an aftermarket steam port setup. Otherwise, the way air is distributed with a plastic manifold, #7 leans out more than the others. The fix is a carb style intake... or the injector/steam port method. This has been known for a good decade or so?
Originally Posted by Darth_V8r
Well cool I ran the steam port. My injectors are matched so nothing I can do there.
Originally Posted by ddnspider
Always been a fan of the 4 port steam vents and always mod the ls6 intake or whatever to fit the stock LS1 4 port vent.
LS7 cylinder cracking It's the steam port setup... #7 runs leaner and hotter compared to the other cylinders. Put your fattest injector on it (if flow-matched or flow-benched) and run an aftermarket steam port setup. Otherwise, the way air is distributed with a plastic manifold, #7 leans out more than the others. The fix is a carb style intake... or the injector/steam port method. This has been known for a good decade or so?
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Steve Demirjian
Race Engine Development
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760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
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Correct on your assessment of cylinder 7 running hotter and leaner making it prone to detonation. A couple of more reasons for this. The LS7 head gasket doesn't provide enough coolant flow around cylinder 7. By the way, cylinder 5 is also prone to cracking but to a lesser degree than 7. Next the factory fuel rail feeds cylinder 7 last which leads to a lean hole. If you pull the plugs when tuning this will be visible. Answer is to replace the fuel rail with one designed for performance use, one with a return line. That will equalize the fuel flow to every injector.