Finally: The LSX 427" Lives!
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
I'm thinking I need to ditch the lid and try to come up with something better. Not sure what I want to try at this point.
TECH Enthusiast
Joined: Jul 2012
Posts: 552
Likes: 1
You know, I still have not gotten my dyno sheets from the tuning session. But, if memory serves me right, I think it was showing 96 kpa. I"m not sure how severe that is, but I know that the transition from the main body to the neck where the coupler fits on the FTP 104 mm lid is the smallest section of the entire induction tract. As a matter of fact that point is really no bigger than the same section on my previous SLP 85 mm lid.
I'm thinking I need to ditch the lid and try to come up with something better. Not sure what I want to try at this point.
I'm thinking I need to ditch the lid and try to come up with something better. Not sure what I want to try at this point.
On The Tree
Joined: Aug 2010
Posts: 108
Likes: 12
From: Cedar Park, TX
Love the build! This is dangerously close to how I would build my dream 427 if I had the funds and my 402 let go. The cam choice is a little surprising for the 255 rectangle port heads, but Pat generally knows his stuff with valve events and cam timing.
I feel your pain on the gear debate. My 3.91s limit me a lot on the big end, but they wake the whole car up on motor. Will see if a taller tire can help me when the bottle goes on.
Bridge City is WAAAAAY east, almost on the LA border. Do you ever venture west for anything? Austin, SA, etc?
Would love to line our cars up. You have a solid setup and more cubes than me, but my race weight is a good 300# less than your f-bod.
Would be fun to get some vids! A cammed Camaro is what got me hooked on LS power way back 14 yrs ago, so any clean, N/A Camaro is always dear to me.
You can send me a PM if you wanna chat. I will be in college station the weekend of 4/24-4/26 doing a road race event.
Congrats on the build, and thanks for posting up the two graphs of the Holley High Ram! I have always wanted more top end out of my motor for years now.
I have ridden in a 13.5:1 CR E85 408ci motor that had the HHR intake and revved out to 8500rpm (absurd and addictive). Car was a built M6 and did not feel punchy like our Fast 102 cars though! He was also in a heavy C5 with iron everywhere and a tall 28" tire out back with stock gears in the diff. Car did almost 70mph in 1st.
Hit 140 on motor in a hurry. 
Keep us posted on the car!
-Michael in Austin, Tejas
I feel your pain on the gear debate. My 3.91s limit me a lot on the big end, but they wake the whole car up on motor. Will see if a taller tire can help me when the bottle goes on.
Bridge City is WAAAAAY east, almost on the LA border. Do you ever venture west for anything? Austin, SA, etc?
Would love to line our cars up. You have a solid setup and more cubes than me, but my race weight is a good 300# less than your f-bod.
Would be fun to get some vids! A cammed Camaro is what got me hooked on LS power way back 14 yrs ago, so any clean, N/A Camaro is always dear to me.
You can send me a PM if you wanna chat. I will be in college station the weekend of 4/24-4/26 doing a road race event.
Congrats on the build, and thanks for posting up the two graphs of the Holley High Ram! I have always wanted more top end out of my motor for years now.
I have ridden in a 13.5:1 CR E85 408ci motor that had the HHR intake and revved out to 8500rpm (absurd and addictive). Car was a built M6 and did not feel punchy like our Fast 102 cars though! He was also in a heavy C5 with iron everywhere and a tall 28" tire out back with stock gears in the diff. Car did almost 70mph in 1st.
Hit 140 on motor in a hurry. Keep us posted on the car!
-Michael in Austin, Tejas
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
Stang2Goat
I appreciate the positive comments. So far I am satisfied with the results of the build, as always I wish it would have made a bit more power. I probably could have made a little more with a LS7 based head, but I already had the rest of the LS3 top end from the previous setup.
The camshaft was actually spec'd by the guys at LME. Since we worked together selecting all of the engine components, I just let them spec the cam as well. Is there more power to be had with a different cam profile? Would have liked to jump on the low lash solid roller wagon, but the valve cover access on the 4th Gen F-bodies absolutely (SUCKS) and is a pain in the *** to take off and adjust valves.
Here is the graph from my chassis dyno session with Pat G. tuning the LSX 427" in my 98 Camaro SS. The car is a full weight pretty well optioned out SS with a 4L85E tranny/ FTI 9.5" Billet Triple Disc conv/ Moser 12 Bolt 3:73 rear, full BMR & Spohn suspension. Race weight is a hefty 3875-3900 lbs depending on how much fuel is in it.
We left some power on the table by keeping the tune a little on the safe side. The tune is a SD tune, we had the power up in the mid 540s and torque close to 530. But, in the name of safety Pat G. and I both agreed to keep it safe ( considering the 12.1 compression on 93 octane pump gas ) and backed the timing down from 28 to a safer 26 degs to better cope with the inconsistent 93 octane pump gas and with the coming hot summer temps. We also left the AFR a little on the fat side as well around 12.4 in the name of safety also. I would rather sacrifice a few ponies rather than deal with the ugly side of the what could happen.
I appreciate the positive comments. So far I am satisfied with the results of the build, as always I wish it would have made a bit more power. I probably could have made a little more with a LS7 based head, but I already had the rest of the LS3 top end from the previous setup.
The camshaft was actually spec'd by the guys at LME. Since we worked together selecting all of the engine components, I just let them spec the cam as well. Is there more power to be had with a different cam profile? Would have liked to jump on the low lash solid roller wagon, but the valve cover access on the 4th Gen F-bodies absolutely (SUCKS) and is a pain in the *** to take off and adjust valves.
Here is the graph from my chassis dyno session with Pat G. tuning the LSX 427" in my 98 Camaro SS. The car is a full weight pretty well optioned out SS with a 4L85E tranny/ FTI 9.5" Billet Triple Disc conv/ Moser 12 Bolt 3:73 rear, full BMR & Spohn suspension. Race weight is a hefty 3875-3900 lbs depending on how much fuel is in it.
We left some power on the table by keeping the tune a little on the safe side. The tune is a SD tune, we had the power up in the mid 540s and torque close to 530. But, in the name of safety Pat G. and I both agreed to keep it safe ( considering the 12.1 compression on 93 octane pump gas ) and backed the timing down from 28 to a safer 26 degs to better cope with the inconsistent 93 octane pump gas and with the coming hot summer temps. We also left the AFR a little on the fat side as well around 12.4 in the name of safety also. I would rather sacrifice a few ponies rather than deal with the ugly side of the what could happen.
On The Tree
Joined: Aug 2010
Posts: 108
Likes: 12
From: Cedar Park, TX
Wise words! You live in between two of the hottest, stickiest states in the union. Car may run fine now in the spring but on a hot summer day it may have to pull a lot of timing out.
I'm 12:1 on my motor and it has only ever pinged in the winter (massive blasts of lean air coming through my OTR intake in the 40* nights this past winter). I run 26* timing. I throw in a bottle of Lucas octane booster for track events like the HPDE I'm doing this month. Always er on the side of caution with your 5-figure engine builds.
I set mine up with a tight quench (.035") and had Brian Tooley polish out the potential hot spots on the chamber edges to stave off detonation. We've had less KR with this setup than we ever had on my old PRC-headed budget top-end from years back (ported LS6 799 castings).
You have good heads, a solid intake, and healthy compression on this motor. Check, check, check. I wouldn't worry about the cam until you've got the rest of the car truly where you want it. The iron block hurts a good 85# but you can run a tubular K, A-arms, and coilovers up front to drop that amount back out of the car.
Need to get the car to RPR in Baytown soon as you get a cool evening to see how the new setup does. Dyno numbers are nice but they've never won a single race. By that I mean your motor setup may be spot-on right now. Won't know until you make a few passes. I'd guess your NA setup easily meets or beats your old nitrous pass ET and trap.
Keep us posted!
I'm 12:1 on my motor and it has only ever pinged in the winter (massive blasts of lean air coming through my OTR intake in the 40* nights this past winter). I run 26* timing. I throw in a bottle of Lucas octane booster for track events like the HPDE I'm doing this month. Always er on the side of caution with your 5-figure engine builds.
I set mine up with a tight quench (.035") and had Brian Tooley polish out the potential hot spots on the chamber edges to stave off detonation. We've had less KR with this setup than we ever had on my old PRC-headed budget top-end from years back (ported LS6 799 castings).
You have good heads, a solid intake, and healthy compression on this motor. Check, check, check. I wouldn't worry about the cam until you've got the rest of the car truly where you want it. The iron block hurts a good 85# but you can run a tubular K, A-arms, and coilovers up front to drop that amount back out of the car.
Need to get the car to RPR in Baytown soon as you get a cool evening to see how the new setup does. Dyno numbers are nice but they've never won a single race. By that I mean your motor setup may be spot-on right now. Won't know until you make a few passes. I'd guess your NA setup easily meets or beats your old nitrous pass ET and trap.
Keep us posted!
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
I agree on the conservative tune and the coming hot summer months. I would rather be safe than sorry for sure, your spot on about the 5 figure engine build ( it snowballed out of control on me quickly ).
I did swap to the BMR tubular K-member & lower control arms to help offset some of the added weight of the LSX block. I also went larger with the exhaust, so that probably added a little more weight back in.
I have made a couple of passes two weekends ago, found I have a couple of issues to address. I need to play with the launch rpms to see where the converter likes to be, either flashed from dead idle, or footbraked up a good bit? I also need to adjust the shift points on the tranny as 2-3 shift is happening too soon. The 3:73s are not letting me cross up high enough throught the traps with the 28" tall tires.
Best pass on the 1st outing was okay considering the circumstances & the hefty raceweight (3900 lbs ). Ran a 10.78 @ 127 mph on a dismal 1.62 60 ft, 1/8th mile times were 6.90 @ 101.70 mph. I drive to the track and back home. My local track is about 37 miles away.
I do make it to RPR several times a year, and always seem to run a tenth or 2 quicker there. Track prep is better there if you get in early before all of the ricers & truckers!
I think when all works out the car should have some 10.30s-40s in it on motor ( may end up going back to the 4:10s ) and some easy mid 9s on the juice ( should mph pretty good with the 3:73s ). Its a shame the car isn't a light weight, would be nice to be around 3200-3300 lbs . But, I told myself I'm not gonna strip this car out just to run the #. It is what it is, a fairly quick heavy "PIG "
I did swap to the BMR tubular K-member & lower control arms to help offset some of the added weight of the LSX block. I also went larger with the exhaust, so that probably added a little more weight back in.
I have made a couple of passes two weekends ago, found I have a couple of issues to address. I need to play with the launch rpms to see where the converter likes to be, either flashed from dead idle, or footbraked up a good bit? I also need to adjust the shift points on the tranny as 2-3 shift is happening too soon. The 3:73s are not letting me cross up high enough throught the traps with the 28" tall tires.
Best pass on the 1st outing was okay considering the circumstances & the hefty raceweight (3900 lbs ). Ran a 10.78 @ 127 mph on a dismal 1.62 60 ft, 1/8th mile times were 6.90 @ 101.70 mph. I drive to the track and back home. My local track is about 37 miles away.
I do make it to RPR several times a year, and always seem to run a tenth or 2 quicker there. Track prep is better there if you get in early before all of the ricers & truckers!
I think when all works out the car should have some 10.30s-40s in it on motor ( may end up going back to the 4:10s ) and some easy mid 9s on the juice ( should mph pretty good with the 3:73s ). Its a shame the car isn't a light weight, would be nice to be around 3200-3300 lbs . But, I told myself I'm not gonna strip this car out just to run the #. It is what it is, a fairly quick heavy "PIG "
Last edited by floman; Apr 13, 2015 at 05:35 PM.
TECH Enthusiast
Joined: Jul 2012
Posts: 552
Likes: 1
I agree on the conservative tune and the coming hot summer months. I would rather be safe than sorry for sure, your spot on about the 5 figure engine build ( it snowballed out of control on me quickly ).
I have made a couple of passes two weekends ago, found I have a couple of issues to address. I need to play with the launch rpms to see where the converter likes to be, either flashed from dead idle, or footbraked up a good bit? I also need to adjust the shift points on the tranny as 2-3 shift is happening too soon. The 3:73s are not letting me cross up high enough throught the traps with the 28" tall tires.
Best pass on the 1st outing was okay considering the circumstances & the hefty raceweight (3900 lbs ). Ran a 10.78 @ 127 mph on a dismal 1.62 60 ft, 1/8th mile times were 6.90 @ 101.70 mph. I drive to the track and back home. My local track is about 37 miles away.
I do make it to RPR several times a year, and always seem to run a tenth or 2 quicker there. Track prep is better there if you get in early before all of the ricers & truckers!
I think when all works out the car should have some 10.30s-40s in it on motor and some easy mid 9s on the juice. Its a shame the car isn't a light weight, would be nice to be around 3200-3300 lbs . But, I told myself I'm not gonna strip this car out just to run the #. It is what it is, a fairly quick heavy "PIG "
I have made a couple of passes two weekends ago, found I have a couple of issues to address. I need to play with the launch rpms to see where the converter likes to be, either flashed from dead idle, or footbraked up a good bit? I also need to adjust the shift points on the tranny as 2-3 shift is happening too soon. The 3:73s are not letting me cross up high enough throught the traps with the 28" tall tires.
Best pass on the 1st outing was okay considering the circumstances & the hefty raceweight (3900 lbs ). Ran a 10.78 @ 127 mph on a dismal 1.62 60 ft, 1/8th mile times were 6.90 @ 101.70 mph. I drive to the track and back home. My local track is about 37 miles away.
I do make it to RPR several times a year, and always seem to run a tenth or 2 quicker there. Track prep is better there if you get in early before all of the ricers & truckers!
I think when all works out the car should have some 10.30s-40s in it on motor and some easy mid 9s on the juice. Its a shame the car isn't a light weight, would be nice to be around 3200-3300 lbs . But, I told myself I'm not gonna strip this car out just to run the #. It is what it is, a fairly quick heavy "PIG "
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
So, you kinda have a good idea of what it takes to "get her up and rollin"One thing I like about my car is, it looks pretty much like a stock F-body with the exception of the Billet Specialties "Streetlites". I run a full exhaust all the way out the back, although it is 4" pipe
I do street drive my car on 93 octane pump gas.Do you have any track times for your car?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo TECH Enthusiast
Joined: Jul 2012
Posts: 552
Likes: 1
Yeah, that's a pretty hefty "ole girl" your hanging out with! So, you kinda have a good idea of what it takes to "get her up and rollin"
One thing I like about my car is, it looks pretty much like a stock F-body with the exception of the Billet Specialties "Streetlites". I run a full exhaust all the way out the back, although it is 4" pipe I do street drive my car on 93 octane pump gas.
Do you have any track times for your car?
So, you kinda have a good idea of what it takes to "get her up and rollin"One thing I like about my car is, it looks pretty much like a stock F-body with the exception of the Billet Specialties "Streetlites". I run a full exhaust all the way out the back, although it is 4" pipe
I do street drive my car on 93 octane pump gas.Do you have any track times for your car?
eventually i'll do the 8.8 and take her to the track, but before then i need to finish up other projects
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
Here is a video of the 1st pass I made a couple of weeks ago. Nothing too impressive, but hope it gets better the next few trips to the track. This is at our local track in Evadale,Tx out in the woods of Southeast Texas.
TECH Enthusiast
Joined: Jul 2012
Posts: 552
Likes: 1
Here is a video of the 1st pass I made a couple of weeks ago. Nothing too impressive, but hope it gets better the next few trips to the track. This is at our local track in Evadale,Tx out in the woods of Southeast Texas.
YouTube
YouTube
Teching In
Joined: Mar 2013
Posts: 32
Likes: 1
From: Upstate NY
The FAST 102mm was not ported at the time of the engine dyno, but I did do some home porting on it before I put the engine in the car. I did a nice port match on the lower base to the head ports, and then matched each intake runner to the base. Finished off by trying to better blend and radius the bellmouth openings of the individual runners. Don't know if I helped or hurt it, but I didn't get too crazy with it. I have port matched quite a few old school single plane intakes in the past, so I think it came out pretty good.
I will start out with a 150 shot, which is what I used on my previous engine. I might go as high as 200-225hp shot.
No, the cam was not spec'd as a nitrous cam per say. But, I did let them know that I would be spraying around a 150-200 shot. I think maybe the idea was to make it run well on motor, and a smallish 150 shot or so is not so critical that the cam needs to be spec'd just for the nitrous. I kinda think maybe he held back on the intake duration intentionally to keep the power peak in line with the rpm range of the FAST intake, and the exhaust side is needed for the cubic inches and 12.1 compression to be sure it exhales properly. I'm no cam guru, but what I had in mind was only off by about 2 degs duration on both int & exh sides from where he was and I was thinking a 113 LSA, where he decided on a 112+4. Who knows if its the best it could be or not, but we will see how the real test at the track turns out.
Here is one engine dyno graph showing the comparison of the Holley High Ram vs the unported FAST 102mm intake both with 90mm DBW throttle body. The Holley intake is the Red lines, and the FAST 102mm is the Black. As you can see, the FAST 102mm kicked *** everywhere except on the very topend.
I will start out with a 150 shot, which is what I used on my previous engine. I might go as high as 200-225hp shot.
No, the cam was not spec'd as a nitrous cam per say. But, I did let them know that I would be spraying around a 150-200 shot. I think maybe the idea was to make it run well on motor, and a smallish 150 shot or so is not so critical that the cam needs to be spec'd just for the nitrous. I kinda think maybe he held back on the intake duration intentionally to keep the power peak in line with the rpm range of the FAST intake, and the exhaust side is needed for the cubic inches and 12.1 compression to be sure it exhales properly. I'm no cam guru, but what I had in mind was only off by about 2 degs duration on both int & exh sides from where he was and I was thinking a 113 LSA, where he decided on a 112+4. Who knows if its the best it could be or not, but we will see how the real test at the track turns out.
Here is one engine dyno graph showing the comparison of the Holley High Ram vs the unported FAST 102mm intake both with 90mm DBW throttle body. The Holley intake is the Red lines, and the FAST 102mm is the Black. As you can see, the FAST 102mm kicked *** everywhere except on the very topend.
A J-1394 correction on the engine dyno would be a more realistic number.
The engine shop may be able to apply that factor to your engine data and give you the 1394 result.
I refer to J-607 as the "bar stool" number.
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
Thanks, hope to get some better vids here soon if it ever quits raining
Jason, you missed out by several months. I sold the ported set I had when I started this 427" build. I have a friend that has a set, but not sure if he would want to sell or not. Good thing is, they are a lot more common now since they put them on the later model 5.3s.
Just did a underground weather search & found a calculator for the conversion. Looks like my engine dyno #s would factor down about 5 hp, so that's not too bad. One pull to the next could vary some, so I'm good with that. Looks like the driveline eats about 100hp & 50 lbft of torque!
Cool setup. I'm sure when you put the boost to it things really start to happen
Did you record any weather data on the chassis dyno day?
A J-1394 correction on the engine dyno would be a more realistic number.
The engine shop may be able to apply that factor to your engine data and give you the 1394 result.
I refer to J-607 as the "bar stool" number.
A J-1394 correction on the engine dyno would be a more realistic number.
The engine shop may be able to apply that factor to your engine data and give you the 1394 result.
I refer to J-607 as the "bar stool" number.
Thread Starter
Joined: Feb 2004
Posts: 621
Likes: 1
From: Bridge City,Tx
I'm always open to different suggestions seeing as this is a totally new combination. Would love to see the car do some high 1.4s-low1.5 60 ft times on motor.
