TIMINATOR

The way I understand your post is that the LS-7 MAF doesn't use an air straightener then? So what if I remove the honeycomb air screen/straightener from the stock MAF and then recalibrate the computer for the increased airflow? Also, has anyone put the entire boat 496 setup in a truck? Intake, cam, manifold, throttle body and injectors? What computer then? What is the stock HP rating for the boat engine? Same pistons? RAYLAR folks comment? Please? Timinator

Whipped383

Tim the magnaflow dual 3 in single 4 out is what I run on my 383 and I love it just use a duramax tail pipe.

On the MAF I agree with the LS7 "card type". Iv been contemplating doing this along with using an LBZ air box. Any MAF other than stock will require calibration. There are mixed opinions on de screening them, most tuners don't recommend it as the screen helps straighten out the airflow across the sensor for a more accurate reading.

Raylar Engineering

The 496 MAG makes 375hp or 425hp if you get the HO variant. The 425hp 496 HO uses a hotter cam to produce the extra power. Both engines are the same as the truck motors but with different exhaust setups. You may be interested in our FAQ page:
FAQ - Raylar Engineering

Yes, lots of people have our street / marine parts on their trucks.
Vortec 8100 8.1L Chevy GM Performance Parts - 496cid BBC Truck / SUV Performance Packages - Raylar Engineering

The computer is the same computer as any LS1 engine. If you're having difficulty with tuning the vehicle, please refer to our tuner list:
Vortec 8100 / 8.1L / 496cid Computer Tuning Links - Raylar Engineering

Doesn't make a difference, they run just fine with or without a screen. All of our vehicles have the screens removed and are very driveable / tuneable.

Whipped383

Everyone has their own opinion on it I recommend doing some research on the matter before hacking it out

Fast355

I have tried multiple MAFs on the same setup. One is descreened, the other fully ported with an added resistor, the 3rd is stock with screen. The less restriction the better the engine runs in my experience. MAF readings and fuel trims seem to hover around normal. I worked on another truck that had driveability issues that I suspected was a MAF. Put the MAF on mine, from the start on it had a very lean feel and as soon as it hit closed loop it immediately had the short term fuel trims peg out into the +20 range. I ended up cleaning the MAF wires with a cutip and CRC MAF cleaner. Slapped the MAF back on the truck with driveability issues, started it up and the short terms went way negative immediately. The MAFs are more sensitive to being clean and having the right flow tables than anything else.

xx_ED_xx

iTrader: (17)

When the first mention of intake manifold restriction they were actually talking about the INTAKE manifold not the pre throttle body stuff.

xx_ED_xx

iTrader: (17)

Fixing the intake manifold and at least a 92 mm tb with a tune will help alot

d-bo71

what do you mean by fixing the intake manifold? and where can you pick up a 92mm tb? I have descreened mine and the truck runs fine I also replaced both o2s upstream erased codes and codes haven't come back yet. Just got rid of my cats also.

Sorry for the stupid questions I did some research and found the answers.

Terminator have yo ported the TB yet?

TIMINATOR

I have ported the TB with good gains, about 12-15% airflow. I have another TB that I will bore and port later and will report. I will be removing the MAF screen and will report airflow changes too. I also have an ls 7 maf to try also. Will have the muffler results probably Monday nite too. Got some more plans for more mods on the airbox too. The gains have been coming along very well so far. I have a line on another intake manifold, will document airflow changes there too. TIMINATOR

Raylar Engineering

The stock intake manifold necks down after the throttle body flange from a 78mm opening at the throttle body to a roughly 55mm opening before opening back up into the plenum of the intake manifold. You can throw all the breathing mods (K&N, bigger MAF, ported throttle body, etc.) you want at the engine, but you're always going to be limited by the stock intake manifold.

Vortec 8100 8.1L Modified Stock Intake Manifold - Raylar Engineering

After you modify the intake manifold, you can run any 3bolt to 4bolt adapter to run an LS2 style throttle body. You will need a wiring adapter to make the 4 bolt style throttle body work with your existing wiring / computer.

We swapped our stock manifold for the modified stock manifold with the LS2 throttle body and made 25hp with stock cylinder heads. You'll make even more with aftermarket units. Here's a video with a dyno comparison of the stock heads with stock manifold versus with modified on our 540 suburban:


And just in case you have a lot more questions, here's Larry on the intake manifold options for the 8.1L engine: