Gmpp cnc ls6 heads and cam combo for ls1
03-30-2017, 10:15 PM
#1
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Gmpp cnc ls6 heads and cam combo for ls1 Purchased some ls6 cnc heads new for a great deal , would like to put them on my ls1 along with a 3000 stall ? and ls6 intake . I plan on driving the car on long road trips from time to time and it will never see the track . Would really like to hear what would be the best cam for maximum tq and hp in a usable rpm range for the street aka light to light . Thank you
03-31-2017, 11:08 AM
#5
After my research I decided to go with a 226/230-113+2 from EPS. I was deciding between that and a 220/226 by them. A close runner up for me was the Street Sweeper from flowtech but I wanted to try EPS lobes.
I haven't started mine up yet but I wanted good all around power as well so it can give you an idea of a few grinds to look at.
I haven't started mine up yet but I wanted good all around power as well so it can give you an idea of a few grinds to look at.
03-31-2017, 11:09 AM
#6
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People are going to kick and scream about way better cams and "omg contact a vendor" but the old GM grinds are nice and gentle on the valvetrain. Leaving some power on the table? Sure, but maximum power isn't everyone's goal.
03-31-2017, 11:33 AM
#7
If it were me I would consider selling the heads and going with something different. They have 250cc intake runners which is way overkill for a stock cube ls1 looking for "maximum tq and hp in a usable rpm range for the street". The port velocity is gonna go to **** with those and for your goals having port velocity is very important. I'm sure the car will put up strong rwhp dyno numbers with those heads but I would be concerned that the car will be a bit soggy down low and will exhibit weak/less than ideal throttle response for what you're looking for. Just something to perhaps look into a bit further before you slap them on.
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03-31-2017, 11:41 AM
#8
If it were me I would consider selling the heads and going with something different. They have 250cc intake runners which is way overkill for a stock cube ls1 looking for "maximum tq and hp in a usable rpm range for the street". The port velocity is gonna go to **** with those and for your goals having port velocity is very important. I'm sure the car will put up strong rwhp dyno numbers with those heads but I would be concerned that the car will be a bit soggy down low and will exhibit weak/less than ideal throttle response for what you're looking for. Just something to perhaps look into a bit further before you slap them on.
03-31-2017, 11:57 AM
#9
I was thinking this as well. Perhaps since he already has them for a deal; consider contacting a cam vendor (EPS or CAM MOTION or BTR) and going conservative since cylinder pressure (cranking compression) and tight quench can help port speed on an over sized runner
OP, if you're adamant about keeping those heads, what this gentlemen mentioned is going to be important to follow.
03-31-2017, 12:30 PM
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Cam choice Thank you for all the feedback , I will have to rethink bolting them on , especially if they won't fit my needs .
Last edited by Ls1time; 03-31-2017 at 12:40 PM.
03-31-2017, 06:02 PM
#11
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The Gmpp heads and ASA cam with a stall will be a nice reliable little package and offer nice gains for the money. The Gmpp heads have quite good low lift flow numbers and work well with the Gmpp ls1 cam grinds. I wouldn't worry about it
03-31-2017, 09:41 PM
#12
OP,
your goals is what a majority of members want. Just a fun daily driver street car, that never sees the track.
with that said, i would just keep your setup simple. Everything has already been done to these cars already.
if i were you i wouldnt go smaller that TSP 228r or no bigger than TSP Torquer 2 232/234.
your goals is what a majority of members want. Just a fun daily driver street car, that never sees the track.
with that said, i would just keep your setup simple. Everything has already been done to these cars already.
if i were you i wouldnt go smaller that TSP 228r or no bigger than TSP Torquer 2 232/234.
04-05-2017, 10:09 PM
#13
GMPP's have big intake ports ~ 250 as mentioned.
So I wouldn't use ~230 cam with them on a 346 that needs good street manners.
A small cam might work OK with those runners in a 346 something like a LPE GT2,-3 207/220.
I'd call LPE and ask for their suggestions since it's a port they designed.
So I wouldn't use ~230 cam with them on a 346 that needs good street manners.
A small cam might work OK with those runners in a 346 something like a LPE GT2,-3 207/220.
I'd call LPE and ask for their suggestions since it's a port they designed.
04-05-2017, 11:27 PM
#14
GMPP's have big intake ports ~ 250 as mentioned.
So I wouldn't use ~230 cam with them on a 346 that needs good street manners.
A small cam might work OK with those runners in a 346 something like a LPE GT2,-3 207/220.
I'd call LPE and ask for their suggestions since it's a port they designed.
So I wouldn't use ~230 cam with them on a 346 that needs good street manners.
A small cam might work OK with those runners in a 346 something like a LPE GT2,-3 207/220.
I'd call LPE and ask for their suggestions since it's a port they designed.
04-06-2017, 08:29 AM
#15
For anyone interested...a few of Tony Mamo's thoughts on the GMPP CNC LS6 heads that I dug up from '04...
"Hey Guys...
Some quick facts on the GM CNC heads......
245 cc Intake port volume (not desirable on stock displacement)
Our testing equipment yielded significantly lower flow data.
Guys....Don't believe every flow figure you read on the internet. Trust me when I tell you that you would be surprised and disappointed more times than not. (And I'm not talking about 5 or even 10 cfm's here)."
Source:
https://www.corvetteforum.com/forums...nder-head.html
I've personally seen good peak hp figures from these heads but peak hp figures don't mean squat for the average joe who truly wants/needs power under the curve and good throttle response. Plus, wasn't the CNC program for these heads designed for and used by GM for road racing? That's what I recall, I could be wrong, could anyone confirm?
"Hey Guys...
Some quick facts on the GM CNC heads......
245 cc Intake port volume (not desirable on stock displacement)
Our testing equipment yielded significantly lower flow data.
Guys....Don't believe every flow figure you read on the internet. Trust me when I tell you that you would be surprised and disappointed more times than not. (And I'm not talking about 5 or even 10 cfm's here)."
Source:
https://www.corvetteforum.com/forums...nder-head.html
I've personally seen good peak hp figures from these heads but peak hp figures don't mean squat for the average joe who truly wants/needs power under the curve and good throttle response. Plus, wasn't the CNC program for these heads designed for and used by GM for road racing? That's what I recall, I could be wrong, could anyone confirm?
04-06-2017, 05:49 PM
#17
This is what my GMPP port heads with stock valves flowed.
radius on intake port. No pipe on exhaust. 4 inch bore @ 28
I think the results were very good for what they cost.
It's my understanding LPE did the CNC port work.
Lift----Intake -----Exhaust
.100-- 64.4 ---44.3
.200-- 134.5 --112
.300-- 198 ----162
.400 --246.5-- 190
.450 ---267 ----197
.500 --281 -----203
.550 --295.8-- 211
.600 --305----- 214
.650-- 285------218
If I recall correctly, LPE wanted to get involved with sponsoring corvette road racing with and developed this intake port. Katech used GMPP heads in some applications - according since LPE was one of the sponsors. It's still a pretty darn good intake port - just too big for a street 346, unless expert care is taken in cam selection.
A friend had the set of GMPP's that I posted flow numbers on above. On a 5.3 with stock manifolds and GT2-3 cam his truck gained 56-58 rwhp. Excellent IMO since long tube headers would like have gained even more.
radius on intake port. No pipe on exhaust. 4 inch bore @ 28
I think the results were very good for what they cost.
It's my understanding LPE did the CNC port work.
Lift----Intake -----Exhaust
.100-- 64.4 ---44.3
.200-- 134.5 --112
.300-- 198 ----162
.400 --246.5-- 190
.450 ---267 ----197
.500 --281 -----203
.550 --295.8-- 211
.600 --305----- 214
.650-- 285------218
If I recall correctly, LPE wanted to get involved with sponsoring corvette road racing with and developed this intake port. Katech used GMPP heads in some applications - according since LPE was one of the sponsors. It's still a pretty darn good intake port - just too big for a street 346, unless expert care is taken in cam selection.
A friend had the set of GMPP's that I posted flow numbers on above. On a 5.3 with stock manifolds and GT2-3 cam his truck gained 56-58 rwhp. Excellent IMO since long tube headers would like have gained even more.
