Stags4

Hey all,

I have a stock high mileage 2000 Silverado 4.8 engine that I plan on throwing some boost at. It's a budget build and don't plan on making crazy numbers but 600-700 hp on e85 is the goal.

Quick question on a few things since it's a hodgepodge of parts.

1) I have an opportunity to get a 2010 4.8 iron block... will that bottom end be "stronger" than my 2000 silverado 4.8? I hear the rods might be stronger?

2) Leave the ring gaps alone? I plan on running a larger than normal turbo for the 4.8 since eventually I might do a LQ4. Maybe an GT45 in the 80-88mm range. I won't mind if it has a little lag and I also don't mind having crap low end.

3) Lastly, and more importantly, I plan to do the "standard" budget build LS9 cam, LS9 head gasket, ARP head studs, 317 heads with upgraded valve springs. I don't know which springs yet. Should I upgrade anything else in the heads other than springs?

4) What push rods do I get? is there a measurement/length I need to get or is this something that will be different for each person/build even with the same components. If it is, how do I measure this? Is there cheap reliable rod measuring tool? Can I use an old rod and either use shims or sand down the rod to find the right length?

svslow

The 2010 motor is a much better option. Everyone has a different opinion on the ring gap. I would advise against the LS9 cam and 317 heads on a 4.8. It has been done, but will drive like crap for a street car and be dead below 4500rpm. Run the stock 4.8 heads.

Stags4

Ok, I'll see if I can get my hands on that motor (still working with the seller but he did say I can have it).


Advise against the LS9 Cam and 317? Even when it's boosted? I hear that's the budget build to actually do. It will be a little bit of a dog low end, but I thought that it's actually not bad for a budget build trying to make some good power. I understand more volume under the curve is better than a spike dyno chart but I it seems like multiple people are having great success with this setup.

The LS9 cam is aggressive for the 4.8 and the 317 puts the compression way low for the 4.8, but I thought if you plan on boosting the vehicle it's the setup to have (if on a tight budget).

Advise on cam then if sticking with the 4.8 heads?

The engine is in a <3200 rat rod so I am not too too worried about streetability, as I won't be driving it everyday but it is somewhat of a concern. I don't want it to be unmanageable and/or uncontrollable due to such a hard HP spike once it comes alive and the tires break loose every time.

Any idea on push rods?

silvea

iTrader: (1)

If you go with stock heads they are stick length. As far as the ls9 can, that's a cam designed to pass emissions and make power on an engine that's 1.4 liters larger and with a supercharger not a turbo. If you really want to be cheap use a Ls6 cam

roastin240

iTrader: (13)

Bail on the LS9 cam....it will make great high rpm power but an aftermarket cam will produce huge gains over it. I should note I have not ran a LS9 cam before, but have 1 friend that has and have seen many setups, dynos and datalogs of turbo 4.8, 5.3, and 6.0 setups with that cam and its not anything to brag about.

Also for your power levels you dont need the bigger valves or higher flowing heads. I would keep the factory heads and do an easy bowl blend on the ports. Your CR and higher port velocity at the lower end will make for a more well rounded vehicle at those power levels...especially considering your going to be running E85 and that CR is a non issue.

JoeNova

1. 2010 4.8 is extremely strong.

2. Depends. Running lots of water/meth or low boost? Might be able to get away with stock gaps.

3. The LS9 cam is not very aggressive. Isn't it a 211/230 on a 122 LSA? It has around -23 degrees of overlap. Thanks to that split and LSA, its pretty much all top-end. Very poor cam choice for an engine that's already small and needs to rev to make power. Same goes for the 317s. You improve flow slightly over the 706/862 heads, but most of that is flow that the 4.8 won't be using. It also drops compression way down. So you'll have a very low compression 4.8 with a cam that doesn't make power until the top end.

4. Push rod selection should be dependent on springs, RPM, ramp rates. Small, mild cam with mild valve springs? Use stock pushrods.

Forcefed86

iTrader: (4)

Nothing very “budget” about a 700whp 4.8 IMO.

I’m on the fence with the LS9 cam. I’ve yet to see someone use it properly on a 4.8. You’d need a converter that stalled to 4k or so NA to get a big turbo spooled up. Then you’d need a top end (and intake) capable of 7500+ and gearing setup to work with that kind of RPM. The gearing and stall required wouldn’t be very street friendly IMO, but it could make 700+ easy if setup right.

You could pick up a stock LS1 cam used for $50 or less and it would work with 100% factory valve train/intake. Then add cheap springs and be done. Howards makes a drop in .600 beehive spring set for $115. PN: 98113. Would work well with the factory intake as well.

No way to know what the ring gaps are without checking. Look at them. If they are .022 or larger on E85 you’re fine IMO.

If you’re doing a budget build with a factory cam, use the factory push rods.

Cesarbambam

LS9 cam 4.8 800hp+

Stags4

Thank you all for the info. I am new to the LS game (actually all domestic and V8 platforms) so pardon my ignorance and lack of knowledge... I have been trying to gain as much knowledge with my limited time. Not new to builds, just new to this realm.

I should have reiterated, what I mean by budget friendly. I built a +700awhp Subaru STI that I put about 30K into the engine... Super fun and had a blast but I don't want to do that again. This build will be a "buy used" or junkyard when I can other than specific things like gaskets, studs, springs, bearings, etc etc. Goal is as little $$ as I can but if another $100 into a better cam/heads for +40hp I am going to do it.

That being said, looks like the LS9 cam could be out and a mild cam could be the better option. Do you have any idea on a specific one or a few? Excuse my ignorance but I don't really understand "211/230" verbage just yet. I just haven't dug into cam specs yet so I am limited on my knowledge.

Someone said LS1 cam another said LS6. Would that be better over a mild "stage 1 boost cam" and would still net me 600-700hp goals (e85)? Any specific parts numbers would be huge for me here.

Anything over .022 for gaps. Got it. I see a lot of people saying .025 so I might shoot for that.

Got the PN for the Howard springs. Thank you!

No meth and it will be a larger turbo than a 74-75mm. I think I might be in the 80-88mm so boost will be lower than a 7Xmm. I think with the 8Xmm turbo I want to be under 15psi, maybe like 10-13psi. Not sure the stock 4.8 can handle much more for a long time however I haven't looked THAT much into it... I just hear they can hit the 600-700 pretty good for a decent amount of time if done right. I understand this won't be a bullet proof engine and I pressing my luck at that range on a stock bottom end, but I would like to see where it lands.

Pro Stock John

iTrader: (34)

4.8 + 317s, low compression no? 9:1 or something?

I'd look for a boost cam, that lil motor will need some help.

Suncc49

I found a used Brian Tooley stage II turbo cam on here for like 200 bucks with 1000 miles on it... do yourself a favor and get a decent cam... Also the 317s will suck on that combo

JoeNova

Your argument is pointless, 800whp has been done on a stock 4.8 cam and valve springs.

tblentrprz

What valve train (springs, etc.) and rpm with LS9 cam at 800whp? Same setup at 26psi and 1067whp?

67Firebird455

iTrader: (27)

Just spun a bearing on my Gen 3 4.8 with 317s and LS6 cam with a billet S475 T4/83-1.10AR. Unless you have a lot of converter, even that setup will feel like a turd down low, but... I was also running 17psi on 91 only without methanol.

What wiped the bearings out was meth/water in the crankcase from holding the test button on the alky control kit, not knowing it was ingesting a ton of fluid. Etched the bearings, and that was that.

Stags4

What numbers are you making?

Another thing to note is this will (eventually) be converted to a manual. I hear the switch to a T56 is a beach but I guess I come from a different world where I can't imagine having a manual other than my Rubicon for off-road trails. Next on the list will be to find a few forums about converting this thing over... That won't be cheap which sucks.

I would rather have fun shifting gears with it on the road course than worrying too much about 1/4 times. To me, anyone can let go of a button and hold a steering wheel. No disrespect to the drag guys, I just prefer a different route with transmissions.

silvea

iTrader: (1)

I'm too lazy to look it up currently but for some reason I'm thinking it's even worse. Like 8.6 or 8.7:1 like super low compression. I mean if you don't mind the spool time and want to run a big turbo you can push big boost numbers on lower quality fuel and make good power. But it will be a dog out of boost then take off like a rocket.

Cesarbambam

Just double springs, chinese head studs, shifted at 7k threw a 4l80 and welded diff and 30" tall tires. I want to say at 26 psi it put down 950 or so

Forcefed86

iTrader: (4)

LS6 cam would be better, but they are a desirable item. So it’s hard to find a good deal on a used one. The ls1 cam is super mild and easy on the valve train. They also aren’t a desirable used cam, so you can get them for little to nothing usually. I’ve had them given to me a few times. Guys have made over 800whp on bone stock ls1’s with the stock cam. It’s just a slight upgrade over the factory truck cam. Aftermarket cam is usually around $365-400+. You’ll likely need better springs than the ones I posted, push rods, and lifters with a semi-radical aftermarket cam. So the price jumps up to $1000+ in some cases. Then add in aftermarket timing sets etc etc… It snowballs out of control quick.

Really need to do a little more research it sounds like. Maybe keep the first build 100% stock long block with valve springs and just work at getting it up and running. Many times beginners will do more harm than good taking engines apart and throwing mismatched parts at the combo. You’ve made a lot of incorrect assumptions above and the time it would take to go through all of them and explain “whats what” would take forever. Especially when all the information you are asking about has been answered 1000 times in these forums if you search.

I can tell you 10-13psi won’t make anywhere near 700whp on a 4.8.

Stags4

That is good info.

Agreed. it can snow ball out of control (I have built too many vehicles that have done that). I also agree I need to do more research, just trying to get a jump start on it by asking the crowd. My goal isn't to mismatch parts unless it's a "proven" setup. I was told by a few people (and looking on the forums) that the 4.8, 317, Ls9 cam, ls9 gaskets, with arp studs and a larger turbo was that "proven mis match". It seems like that isn't the case due to small L and extremely low compression.

10-13psi won't make 700whp on a small turbo, but possibly (and of course given many other mods) it could on a large one since psi is only a measurement of force and not volume. Again, the number isn't too concerning to me just just a little bit of a goal and sure a 4.8 could make that, but at what cost and comfort. I like to focus on the volume under the curve so even if I make 500-600 with a nice curve first round I will be ok. Just seeing whats out there. The next build will be a lot wilder.

Forcefed86

iTrader: (4)

With a turbo LS setup, short/long blocks have become the cheap part of hot rodding. You can have 2-3 spares waiting to drop in…

The small VS large turbo comment isn’t relevant to my post. Assuming a turbo was 100% efficient the best it can do is double the NA HP output at the crank per bar of boost. So if you have a JY 4.8 with an LS1 cam, you’re lucky to make 290hp at the crank. Assuming 100% efficiency the best you could do is double that 290HP at 14.5lbs or so. In actuality turbo systems are more like 70-75% efficient. So realistically you are looking at around 500 crank HP at 14.5lbs on a properly setup turbo system. Using a smaller less efficient turbo is only going to drop that number. Factory gen4 LS 4.8’s are being pushed well past the 1000crank hp range. You can run a ton of boost IF the tune is right. My small aftermarket cam 4.8 in a 3000lb chassis went 9.0 @151 on about 20lbs. Which is about 700 at the wheels going by weight and trap.