408 lt1
When I say it ran fine I am talking for a matter of maybe 10-15 seconds. I said nowhere MAN I WAS MAKING SOOO MUCH POWER I DONE DID SNAPPED MY DANG GONE CRANK'EM SHAFT. I implied that maybe it was a weak casting and it broke for unknown reason. I'm positive along with others that have seen every piece of the motor that the crankshaft broke first. It's old news dude, it happened last August. Most of the broken parts are long gone.
This is highly simplified, since there is a lot more to it the just LSA. The real thing to look out for with cylinder pressures is the intake valve closing and the timing events of the cam being used. This is why you need a professional to spec a cam, and cant just throw out xxx/xxx duration with .xxx/.xxx lift and xxxLSA and expect to always get the results you want.
Last edited by Puck; Jan 6, 2009 at 10:39 AM. Reason: simplified for clarity
oh yeah, i forgot to mention, there were a few 421ci LT1s out there. another poster mentioned MTI and i think Darrel Jimmerson's shop built a few also. i only remember one though that was daily driven. it was a silver grey 96 or 97 Z28. if i can remember the taillights, i think it was a 97.
Thread Starter
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
The biggest thing with tight LSA cams is they shut the intake valve sooner as compared to a wider LSA. With a tight LSA it takes a bigger lobe to bleed off the cyl pressure. Overlap does have some effect on cyl pressure but the closing of the intake valve is really the key factor in deciding what the cyl pressure is gonna be.
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Thread Starter
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
Oh dear god. I dont recall sayin that they make em perfect. But they will make em alot close than youll ever get them with a grinder. Umm um wow. Some people amaze me.
A good head guy wil be better than your average CNC machine that is making profit off a few hundred dollars/head. Some of the better CNC machines can more accurately mimic a port, but if you run tighter tighter resolution/accuracy, it takes more and more machine time and that cuts into profits, 99% of businesses profits actually affect decision making, whodathunk? Sometimes it means sacrificing max possible Q and QC
The problem lies in policing "good cyl head guys" THey all say they are good, but are often not. There is only a few good guys that mess with LS1 stuff, and thats probably stretching it. Buyit/tryit is the only way to know for sure... and at that point they already made their $$$
The problem lies in policing "good cyl head guys" THey all say they are good, but are often not. There is only a few good guys that mess with LS1 stuff, and thats probably stretching it. Buyit/tryit is the only way to know for sure... and at that point they already made their $$$
