Okay everyone I'm looking for some expert opinions here.

Currently I have 2001 SS 6 speed with 90,4xx miles. I have a Huron Speed turbo kit t4 AC retention kit. I did not buy it with a turbo at the time because I was I sure of my direction.

Now comes the time for me to chose that direction.

I have a 4.8 that I bought when I thought I wanted to go that direction. However, I'm seeing the make great power and hold the power well. But I'm reading a lot of people say the motor is a dog outside boost.

The car is going to be a weekend street car. I'm shooting for 650hp. I want it to be as reliable as can be.

Should I keep the 4.8 or use the 5.7. Also with the 5.7 should I just throw a set of pistons/rods with a set of 317's and a good cam in it. Or just use the stock 4.8 and boost the hell out of it.

For a turbo I was pretty set on the s475 with the 4.8. If I keep the 5.7 should I go a different turbo.

I'm pretty set on fuel: twin Walboro 255's with 80lb injectors

Clutch I believe I'll be going with a mcleod rxt but uncertain on flywheel.

Rear end will be stock until it blows up then a s60 or 9"

If anyone could yield some big help here. I'm at the point when the trigger is going to get pulled on a lot lf money. Don't want to spend it then switch it up later

 

Screw the 255s and use a Walbro 450 with a hotwire kit.. just incase you ever wanna run e85.
Personally, id use the 4.8. Slap it in stock or chinese head stud it and boost the living **** out of it

 

what year 4.8? watch out for the rods in the early ones, my first on chucked the rods through the block...
Im running 9.5x on only 14 psi with my 4.8 at 3400lbs.. which is right around 625rwhp by the math..
it runs fine pre boost but its a whole different animal once boost hits.. people have no clue how fast it really is driving it around, sounds like a cammed small block with exhaust..

 

The 4.8 is out of a 01 Sierra. I just want to make sure that if I use the 4.8 its going to be enjoyable driving. I'm building the car to be a weekend fun car. I don't want to hit boost EVERYWHERE.

 

The better rods/pistons came in 04.5 and later, another thing to consider is your 5.7 is worth descent money for NA swaps, and the earlier rods are still proven pretty reliable around 600-700hp. Depends on what your goals are.

 

i would sell the 5.7 as itll fetch some decent money and do rods and pistons in the 4.8 for when you really want to turn it up. I would get with Jose and Forced inductions and Martin at tick and make sure that you cam and turbo will work together nicely for the boost range that you're looking for.

 

4.8 or 5.3 would work well.

 

So no one here seems to think the 4.8 wouldn't still be an enjoyable drive for street driving out of boost. Don't get me wrong the car will see a ton of boost. I am a very spirited driver. But for a weekend cruiser I want it to be enjoyable from all angles too. No one thinks a 4.8 would be crappy outside of boost?

 

I have a 4.8 in my truck and it gets the job done at 4300lbs, knock anywhere from 500-700 off that and youll be fine outside of boost specially with the right cam/heads

 

That's good to hear. Definitely looking for enjoyment when driving.

 

I'm building several 4.8 motors so I'll let you know to replace my old alum ls6

the 4.8 will still make plenty of torq the block is really strong and the short stroke allows a bit broader RPM band to really zing the boost and stay in it longer

alot of this depends on driving style and vehicle too.

In my case they are going in relatively lightweight vettes and the lower torq actually helps hook the car to ramp the boost up a bit more progressively

with the right turbos and cam, the car will spool pretty quick and still blow the tires off in a heart beat on boost

boost makes up for CI to an extent and with the modern turbos and quick response of FI you won't miss the longer stroke