cirvin33

Alright guys, this is my first post on this forum so forgive me for my greenness.

Truck- 07 silverado classic with a 4.8L

I am very into the diesel scene but started out with gas engines so I am not a total newbie. I have done quite a bit of searching but haven't quite found the info I am needing. I have the truck listed above and I am wondering if the hp I listed is reachable with a naturally aspirrated 4.8 and if not then how high is? I sent blackbear (i believe that was the name) an email earlier on tuning but I am wonder what other hard parts are needed (what size cam, vs to match the cam, intake, what # injectors, etc.).

This truck is basically the grocery getter but I would like to make it a bit of a sleeper. Any info you all could give would be awesome and I am a tech (ATC Freightliner Dallas) so I am not a typical diy'er, I just don't know much about the ls series engines. Thanks in advance guys!

One more thing, how much is the 4l60 good for? And also what mods are needed for the 400hp range? Bash away!

chopperman69

iTrader: (-1)

On my 3rd 4L60E with a bone stock 4.8L...

Can't think of anything they're good for.

gregrob

iTrader: (8)

Very possible with the right heads cam intake...

bww3588

iTrader: (49)

I would send the heads off to advanced induction to be ported, call up pat g for a cam, full exhaust, and look into a fast lsxrt intake manifold, good cai and a really good dyno tune. No reason you shouldn't see 400 at the crank.

chrisfrost

iTrader: (8)

The 4l60 can hold up if prepared with the right parts for instance 1. Hardened pump vein rings 2. 7-vein pump 3. 9-clutch high heat/friction clutch packs 4. rear planetary with a dam 5. Gil Younger No Yo Yo complete shift recalibration kit.

cirvin33

Good info, thanks. I would have been on here to reply earlier but I never got any email.

Any thoughts on injector size/brand?

bww3588

iTrader: (49)

Check out injector connection.

custm2500

iTrader: (11)

You are going to be pushing it fairly hard to make 400 from the 4.8 N/A. You boost it and guys are running 10s obviously making much more then 400 at the crank. Turbo, injectors and you should make 400 without a problem.

I am not saying it is imposible but it would be very dificult. Goodluck.

raymond mckinney

iTrader: (4)

Before you waste money,time and energy into the 4.8l i would sell it and buy a 6.0l from a junkyard or ebay and swap it into your truck as its as cam and header swap away from 450hp.

bww3588

iTrader: (49)

Why no love for the 4.8? Yes you can make more power from a larger engine but **** people...its not a Honda engine.

To everyone saying it's going to be hard to hit 400 with a 4.8...go tell that to the 5.0 mustang guys doing it with worse heads and only 10 more cubes.

cirvin33

Thanks, I will check them out.

Everyone else- I appreciate the feedback but i'm not interested in doing a swap or anything until this ones petered out. And I really dont want a turbo either. The truck doesnt have to be exactly 400hp. I just want it somewhere in that neighborhood.

chopperman69

iTrader: (-1)

You can get to 400 HP, but you're in a heavy truck. You need to focus on building torque and that's not exactly easy to do with a 4.8L. You could bolt on a supercharger but then the 4L60E won't last long. Hell, I'm convinced in a heavy vehicle like a truck, a 4L60E won't last regardless of what you do to it. That's why the truck guys usually step up to the 4L80E. But that's not exactly cheap to do...

mark21742

Since you should have plenty of hood clearance (10 3/4" from valley cover to top of intake) look at the Edelbrock proflo xt. I picked mine up through Summit Racing for $365.....did some porting in it and LOVE it!

A few options for you, if you want more cubes you could swap out your crank since it has a shorter stroke than any other motor (5.3, 5.7, 6.0 all share the same crank), but then you would need 5.3l rotating assy also.

If you want to keep it a 4.8 I'd get the compression up as high as you can by either a piston swap, or milling the hell out of your heads. Then go with a 224/230, 228/232 and just under .600" lift tight lsa around 110-112 with a great set of beehive springs and you should be at or above your goal.

Turbo or supercharger, injectors and a tune will put you way over your goal easily.

cirvin33

well it would be as cheap to put in a 6.0 as it would a supercharger.

cirvin33

I like the price on that intake alot better. So will a 5.7 crank from say a 96 truck fit? I actually have a 305 in the garage from a 96 (i know its same crank) I just didnt realize they were interchangeable. If I could go that route then I would love to make it a 350.

mark21742

Has to be ls based, sorry.....4.8 is a destroked 5.3, 5.3, 5.7, 6.0 just have different bore sizes but has to be part of the LS family

mark21742

Here are a few pics of my intake after some grinding and polishing on the outside of it too

cirvin33

Damn haha. what is the bore & stroke on these engines anyway?

mark21742

Lol like I said, it is tall

mark21742

In the stickies st the top of the gen3 internal engine section I think there is a list of all the specs for each engine