6.4L 388 ls3 dyno guesses?
#22
10 Second Club
Thread Starter
#23
TECH Fanatic
Join Date: Aug 2009
Location: Coast of San Mateo County Between Pacifica & HMB
Posts: 1,827
Received 233 Likes
on
137 Posts
Steps to prepare Drivetrain,Suspension, and break in a new clutch
Before installing the 396" in my C5.
#24
TECH Fanatic
Join Date: Aug 2009
Location: Coast of San Mateo County Between Pacifica & HMB
Posts: 1,827
Received 233 Likes
on
137 Posts
The split is all about the E/I Relationship.
Speaking NA The MAST Medium Bore LS3s are one of the best
LS3 Heads out of the Box IMO, comparing E/I relationship
From .300"-.600" is 84%-70%
My MAMOFIED TFS LS3s are 83%-68% (with slightly higher gross #s)
The MAST Big Bore 280CC Runners are 70%-64%
MMS 220s,235s are 85%-75% again at the same valve lifts
.300-.600".
So you can see the MAST Med Bore Heads have a E/I relationship
Much closer to MMS Cathedrals VS even Good aftermarket Square Ports.
Point being 6*-10* is probably the sweet spot for efficient E/I
LS3 Heads NA from 7000-8000 RPM.
VS the more typical 12*-16* splits seen with OEM Rectangle Ports.
In Big Hammer,s situation 14* will help carry beyond 7500 RPM
and only be a little soft below 3500 RPM (VS 10* split) which
I am sure he could care less about.
We are "almost" splitting hairs at this point.
I always value and get a lot from your threads & posts.
#25
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,452
Received 1,852 Likes
on
1,152 Posts
Originally Posted by NAVYBLUE210
Darth,
The split is all about the E/I Relationship.
Speaking NA The MAST Medium Bore LS3s are one of the best
LS3 Heads out of the Box IMO, comparing E/I relationship
From .300"-.600" is 84%-70%
My MAMOFIED TFS LS3s are 83%-68% (with slightly higher gross #s)
The MAST Big Bore 280CC Runners are 70%-64%
MMS 220s,235s are 85%-75% again at the same valve lifts
.300-.600".
So you can see the MAST Med Bore Heads have a E/I relationship
Much closer to MMS Cathedrals VS even Good aftermarket Square Ports.
Point being 6*-10* is probably the sweet spot for efficient E/I
LS3 Heads NA from 7000-8000 RPM.
VS the more typical 12*-16* splits seen with OEM Rectangle Ports.
In Big Hammer,s situation 14* will help carry beyond 7500 RPM
and only be a little soft below 3500 RPM (VS 10* split) which
I am sure he could care less about.
We are "almost" splitting hairs at this point.
I always value and get a lot from your threads & posts.
The split is all about the E/I Relationship.
Speaking NA The MAST Medium Bore LS3s are one of the best
LS3 Heads out of the Box IMO, comparing E/I relationship
From .300"-.600" is 84%-70%
My MAMOFIED TFS LS3s are 83%-68% (with slightly higher gross #s)
The MAST Big Bore 280CC Runners are 70%-64%
MMS 220s,235s are 85%-75% again at the same valve lifts
.300-.600".
So you can see the MAST Med Bore Heads have a E/I relationship
Much closer to MMS Cathedrals VS even Good aftermarket Square Ports.
Point being 6*-10* is probably the sweet spot for efficient E/I
LS3 Heads NA from 7000-8000 RPM.
VS the more typical 12*-16* splits seen with OEM Rectangle Ports.
In Big Hammer,s situation 14* will help carry beyond 7500 RPM
and only be a little soft below 3500 RPM (VS 10* split) which
I am sure he could care less about.
We are "almost" splitting hairs at this point.
I always value and get a lot from your threads & posts.
Look at it this way. If you do 45 IVC and 55 EVO and zero overlap, you'll get 10 degrees split.
For high revving, gotta open that valve to make room for fresh stuff!
And the respect is mutual my friend. I'm just really excited to see where hammer ends up. At 5 CI more than the every day 383, this thing is going to really shine vs the 383. Imo 3.62" stroke is plenty for torque. I feel like GM got that one right.
#26
11 Second Club
Come on darth. I thought we weren't going to compare this motor to a normal 383. Which is completely different. Lol.
I have to check my phone & see how many tow jobs came in. Lol.
I have to check my phone & see how many tow jobs came in. Lol.
#27
10 Second Club
Thread Starter
I emailed mast to see if they knew what these heads flow on a 4.125" bore. They advertise fnumbers for a 4.070 bore. Short answer they don't know for sure, just "more". Lol
#28
TECH Veteran
Darth... a well RESPECTED cam/head guy told me on the phone about camshafts with rectangle heads.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip......
So in my words you have to be very careful with splits.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip......
So in my words you have to be very careful with splits.
#31
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,452
Received 1,852 Likes
on
1,152 Posts
Originally Posted by Tuskyz28
Darth... a well RESPECTED cam/head guy told me on the phone about camshafts with rectangle heads.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip......
So in my words you have to be very careful with splits.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip......
So in my words you have to be very careful with splits.
#32
10 Second Club
Thread Starter
Darth... a well RESPECTED cam/head guy told me on the phone about camshafts with rectangle heads.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip...... .
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads
Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.
Basically what looks all good on paper isn't milk and cookies at the drag strip...... .
Mph shows hp. Et shows track efficiency.
I've only been to the track like 4 times in my life and almost always with different setups. So track efficiency I don't reallly have a handle on yet
#33
TECH Veteran
6.0 Motor with LS3 heads mainly..... pm me and I'll tell you who mentioned it to me. He also said the rectangle port heads are very sensitive to overlap which makes them even harder to cam "sweet spot". I know mph shows hp. Hell it's a 427ci on here that traps 131 mph and runs 10.7 to 10.9 e.t. On the other hand it's ws6 on here traps 129 at runs 10.5 over and over. Both 6 speed F body cars.
#35
11 Second Club
Keep on living & maybe you learn a little.
You should be less of a douche.
Oops, I acted like Hio..
#36
If a guy's running 131 on the top-end with a 10.7. Whats the 60 foot? The rear gear? and car weight? Car sounds soggy on the launch and not Properly set up for the track.
Hell John B. did 10's in the Monte Carlo and made 700 rwhp so does he need to re cam the car. There are many factors for the track and each car & build is different.
Hell John B. did 10's in the Monte Carlo and made 700 rwhp so does he need to re cam the car. There are many factors for the track and each car & build is different.
#37
10 Second Club
Thread Starter
6.0 Motor with LS3 heads mainly..... pm me and I'll tell you who mentioned it to me. He also said the rectangle port heads are very sensitive to overlap which makes them even harder to cam "sweet spot". I know mph shows hp. Hell it's a 427ci on here that traps 131 mph and runs 10.7 to 10.9 e.t. On the other hand it's ws6 on here traps 129 at runs 10.5 over and over. Both 6 speed F body cars.
Doesn't mean ls3's are crap, they just have their place. If you're goal is to build a 6.0 with the intention of shifting around 6500 I'd be more apt to stick with a stock cathedral casting over a stock ls3 casting. But if you want to build a 6.0 to rev to 7500-8000, ls3 me all day
#38
TECH Veteran
If a guy's running 131 on the top-end with a 10.7. Whats the 60 foot? The rear gear? and car weight? Car sounds soggy on the launch and not Properly set up for the track.
Hell John B. did 10's in the Monte Carlo and made 700 rwhp so does he need to re cam the car. There are many factors for the track and each car & build is different.
Hell John B. did 10's in the Monte Carlo and made 700 rwhp so does he need to re cam the car. There are many factors for the track and each car & build is different.
On the other hand the car was on drag radials and was sideways for the first 60ft out.
#39
10 Second Club
Thread Starter
I should have clarified. For carrying past peak I tend to see larger splits. Especially on rectangles. For hammers rpm goals, we sorta came up with something close to what he ended up with. In the end, Kip speced it out for him. But I also tend to like more exhaust in general. I like to open that valve early to vent the chamber down sooner. Then if you maintain any overlap at all, you end up 8+ split.
Look at it this way. If you do 45 IVC and 55 EVO and zero overlap, you'll get 10 degrees split.
For high revving, gotta open that valve to make room for fresh stuff!
And the respect is mutual my friend. I'm just really excited to see where hammer ends up. At 5 CI more than the every day 383, this thing is going to really shine vs the 383. Imo 3.62" stroke is plenty for torque. I feel like GM got that one right.
Look at it this way. If you do 45 IVC and 55 EVO and zero overlap, you'll get 10 degrees split.
For high revving, gotta open that valve to make room for fresh stuff!
And the respect is mutual my friend. I'm just really excited to see where hammer ends up. At 5 CI more than the every day 383, this thing is going to really shine vs the 383. Imo 3.62" stroke is plenty for torque. I feel like GM got that one right.
Since long stroke small bore by nature tends to increase volumetric efficiency, I bet set of mast small bore ls3's on a 383 engine would make a killer engine.
#40
TECH Veteran
383s get a bad Rep cause the guy don't know how to pick the correct heads and cam. Richard Holdnerer did one.... It produced 605hp at the crank using TEA heads and a 239 duration cam.