LS7 427 vs 440 question
But there are people, on this site, with big *** engines.....that have a top end that doesn't match and they make just a little bit more HP than engines with 50+ less cubic inches.
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Its just something poeple like to always bring up as a negative thing to say about using the LSX iron block.
Read the link below: The two fastest 1/4 mile LSx cars out there. Page #2, post #21.
He explains how the extra weight is a POSITIVE, and using the iron block he gets the added safety and reliability.
What do you think the extra weight of the iron block is slowing him down....maybe .02 seconds in the 1/4 mile. The more power you make the smaller the effect that extra weight has on ET. I'd rather be able to make a bunch more reliable power with an iron block to make up for that extra weight....then have to run an aluminum blocked engine near the ragged edge to compete.
https://ls1tech.com/forums/forced-in...s-warhawk.html
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A4...close
M6...for sure
There's a bunch of 427's over 600 RWHP like that witgh less compression, it would be a little easier with a 440ci.
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FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
In many of not most areas if the country that is too much from what we have seen. You have to start pulling timing and any bad gas or really hot weather and you performance is substandard. You will make better dyno numbers on a cold engine though for sure.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
I'm not saying the other guys are dead wrong but we couldn't run that much compression.
I usually run about 11.25 but have run as high as 11.5 on some much bigger cam racier stuff that isn't a daily driver or going to sit baking in ruch hour traffic.
I usually run about 11.25 but have run as high as 11.5 on some much bigger cam racier stuff that isn't a daily driver or going to sit baking in ruch hour traffic.
Ok i am very comfused now 
. I see some guys that claim they are running 12 to on street driven cars then i talk to some guys that tell me 11.5 is the limit. I dont see much driving above 3000 Ft and 90% of the time the car is is lower then 1000 Ft. NC gets gets up in the 90s in the summer but thats about as bad as it gets. I dont plan to put more then 3000 miles on this engine a year but i would like it to last at least a few.
. I see some guys that claim they are running 12 to on street driven cars then i talk to some guys that tell me 11.5 is the limit. I dont see much driving above 3000 Ft and 90% of the time the car is is lower then 1000 Ft. NC gets gets up in the 90s in the summer but thats about as bad as it gets. I dont plan to put more then 3000 miles on this engine a year but i would like it to last at least a few. Ok i am very comfused now . I see some guys that claim they are running 12 to on street driven cars then i talk to some guys that tell me 11.5 is the limit. I dont see much driving above 3000 Ft and 90% of the time the car is is lower then 1000 Ft. NC gets gets up in the 90s in the summer but thats about as bad as it gets. I dont plan to put more then 3000 miles on this engine a year but i would like it to last at least a few.
. I see some guys that claim they are running 12 to on street driven cars then i talk to some guys that tell me 11.5 is the limit. I dont see much driving above 3000 Ft and 90% of the time the car is is lower then 1000 Ft. NC gets gets up in the 90s in the summer but thats about as bad as it gets. I dont plan to put more then 3000 miles on this engine a year but i would like it to last at least a few.
Pump gas compression ratio Erik,
You are 100% correct on the ratio. The LS7 blocks I get in here with cracked walls all pushed the limit to 12:1 or more. Better be safe than sorry with the crap gas available today. You would be hard pressed to notice a half point difference on a street car regardless.
Back in the old days, before most of you guys were born, I used to run 12.5:1 on the street. That was when Sunoco 260 was available at the local gas stations back East.
Steve
You are 100% correct on the ratio. The LS7 blocks I get in here with cracked walls all pushed the limit to 12:1 or more. Better be safe than sorry with the crap gas available today. You would be hard pressed to notice a half point difference on a street car regardless.
Back in the old days, before most of you guys were born, I used to run 12.5:1 on the street. That was when Sunoco 260 was available at the local gas stations back East.
Steve
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
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
I love how the ceiling keeps being pushed with these NA builds despite suspect gas, while still having the ability to be reliable. Who would have thought 9yrs ago, 575rwhp out of a NA/LS motor would fairly common.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
As far as the 12:1 compression issue. Just because you can go 12:1 doesn't mean that you should. I think most people miss that.
Sure, you can bleed off some presure with the right cam, but by doing so, you wouldn't really be running an optimized setup. JMHO
Sure, you can bleed off some presure with the right cam, but by doing so, you wouldn't really be running an optimized setup. JMHO