Lt1 flowsheet question
Thread Starter
Melting Slicks
Joined: Oct 2005
Posts: 3,178
Likes: 5
From: Daleville Indiana
St. Jude Donor '08
Lt1 flowsheet question
I'm looking at buying a set of ported heads with this flowsheet
[IMG]
[/IMG]
My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
[IMG]
[/IMG]My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
Instructor
Joined: Jun 2006
Posts: 195
Likes: 0
From: Canyon Country CA
Flow is not just about size. The better heads are able to flow more with smaller ports and therefore higher port velocity and low end performance. If you want to get a rough comparison, look at the AFR onling catalog. They provide flow data on their various heads by intake port volume.
The best recommendation would be to talk to the folks that did the porting. With a detailed description of the engine you plan to build they should be able to give you an assesment of the performance range.
The best recommendation would be to talk to the folks that did the porting. With a detailed description of the engine you plan to build they should be able to give you an assesment of the performance range.
Melting Slicks
Joined: Jul 2004
Posts: 2,695
Likes: 0
From: Chicago Illinois
intakes may run out of breath to soon
Those are huge flow #s. I would think you will need a great big cam to match. Which intake I dont know. My guess would be the smaller the better. Those tq monster intakes may run out of breath to soon to maxamize the potential of those heads. Those are the largest #s Ive seen out of a LT head.
Originally Posted by Jonnymac
I'm looking at buying a set of ported heads with this flowsheet
[IMG][/IMG]
My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
[IMG]
[/IMG]My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
Safety Car
Joined: Sep 2003
Posts: 3,692
Likes: 5
From: Hayward CA
Originally Posted by bobmic93
Those are the largest #s Ive seen out of a LT head.
I've only seen those kind of numbers from ported to the max LT4 heads, not LT1. Are you sure those are LT1 castings?
Thread Starter
Melting Slicks
Joined: Oct 2005
Posts: 3,178
Likes: 5
From: Daleville Indiana
St. Jude Donor '08
They are stock Lt1 heads 10128649 93 F-body I think. I've seen lt4 heads flow this much but not LT1s. Is it true that the stock intake can not flow over 300 cfm? My plan was match the LPE 219 cam with a 195cc head with a good E/I %. I did not want to run a big cam as I will not be on the track much. To me a smooth running engine is more important then a 500hp+ dyno queen.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by Jonnymac
I'm looking at buying a set of ported heads with this flowsheet
My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
I've seen other LT1 heads with those kind of numbers and it was after $2500 in head work.
Worst case scenario, you decide they aren't what you want, and you resell them for a huge profit.
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Le Mans Master
Joined: Jul 2000
Posts: 5,012
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From: OKC OK
I’d be very skeptical of those flow numbers & heads...tell (or find out) more info....reputation & references of the porter (i haven't heard of them), was a pipe used to flow the exhaust, valve sizes, runner volume, cchamber volume, min. cross section area, valve spring specs, a lot more pics, etc.
Burning Brakes
Joined: Oct 2006
Posts: 834
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if this is intended to be a street car without atleast a 396 or SC mod these heads are too much flow your port velocity will slow down way too much and hurt power. If you want to hot rod the F out of that motor and the numbers are correct then buy the heads. keep in mind what do you want these heads are for a serious RACE engine (by the provided flow numbers) a lot of people look at AFR's web site and say sh!it I want the comp heads with the 190cc intake when if all they want is a street killer theses heads will actualy result in less power due to the drop in port velicity. simply put if the intake port velocity is to low then the full charge of fuel air mix cant get into the engine therefore less power than if you don't fourced air or NO2 the engine. since fouced air above a certiain press negates port velocities since the port is always presurised and when the intake valve opens there is sufficant D/P behind it to fource the air fuel mix into the cylnder
final thought great race heads not so good street heads so what do you want your car to be?
final thought great race heads not so good street heads so what do you want your car to be?
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
I thought I remembered the name VPE from somewhere.
http://web.camaross.com/forums/showt...&highlight=vpe
Get those flow numbers independently verified before you buy.
http://web.camaross.com/forums/showt...&highlight=vpe
Get those flow numbers independently verified before you buy.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Originally Posted by Jonnymac
I'm looking at buying a set of ported heads with this flowsheet
[IMG][/IMG]
My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
[IMG]
[/IMG]My question is how big would the intake runners have to be to flow this much out of a stock LT1 head. The owner did not know. Right now I've got a stock bottom but the plan is to build a 396 when the Vette is paid off next year. From what I've read anything over 200cc kill low end torque on the street. So should I pass on the heads selling for $1000. VPE did the porting.
remember stock LS1's come with either 204cc or 206cc from the factory stock.
if those are the flow #'s, they flow AMAZING.
Thread Starter
Melting Slicks
Joined: Oct 2005
Posts: 3,178
Likes: 5
From: Daleville Indiana
St. Jude Donor '08
If Lloyd Elliott is calling VPE's flow numbers 
then it must be. So its back to my old plan. Like they say if it sounds to good to be true...
I need a new clutch a lot more then heads anyway.
then it must be. So its back to my old plan. Like they say if it sounds to good to be true...I need a new clutch a lot more then heads anyway.
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
What are the valve sizes? That would give you an idea if the # are for real. It would take at least a 2.05 to flow that, if not a 2.08. Need better pictures too. You can barely see the ports anyway.