fergymoto

iTrader: (129)

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.

slowpoke96z28

iTrader: (2)

i thought the tighter LSAs were better for high compression. i cant remember where i heard that from.

Puck

iTrader: (17)

High compression favors an LSA with more overlap because it bleeds off cylinder pressure due. That is why static CR can be high, but dynamic still in check when using a lot of duration and a numerically lower LSA cam. That is also why you WANT high compression with a big NA cam, because it keeps you from losing as much low end tq that gets sacrificed by the valve overlap needed for a high rpm NA cam.

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.

slowpoke96z28

iTrader: (2)

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.

94LS1B4C

iTrader: (3)

Did you reuse the crank?










.................. lol j.k

wht97ws6ta

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.

GrannySShifting

iTrader: (10)

CNC doesnt mean perfectly equal. Just means a machine did it, good or bad.

18 cfm differences in a siamese port head, CNC'd Ive seen it

nichols92

Hey Puck, how did you make 609RWHP NA? Seems really high for an LT1

BizZzatch350

iTrader: (33)

His sig is a joke.

FASTFATBOY

iTrader: (23)

Uhh no, he runs 11.70's (last I heard) But sees fit to crack on cars faster than his.

nichols92

I kinda thought something like that. Mine only does 449RWHP NA and I thought that was good.

wht97ws6ta

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.

GrannySShifting

iTrader: (10)

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 $$$