z28C4maro82z

iTrader: (33)

Hey guys! Looking to order up the remaining parts for my build. Wanted to know what you guys thought I should finish getting

Motor: 4.8

What head gaskets should I run? Ls9 gaskets?

Should I just run the stock 862 heads?

Arp head bolts

60 or 80lb injectors

Twin Walbro 255 or single Walbro 400

Turbo: s475/83mm/1.10

What clutch should I run? McLeod twin rxt?

I have basically everything else needed...just up in the air on a few of these miniature things. I know you guys will help! Thank you in advance guys!

-Chris

z28C4maro82z

iTrader: (33)

Sorry, also need to know what wastegate to use

z28C4maro82z

iTrader: (33)

Sorry, also need to know what wastegate to use

SM105K

iTrader: (3)

I have these for my 4.8 SS. I have an APS twin turbo kit strapped to mine. It is an E85 car with a Powerglide.

Head Gasket: LS9
Head Studs: Chinese
Heads: Worked 862's with Comp Hardened Push Rods and PAC .600 lift springs
Injectors: Siemens Deka 80's
Fuel System: Lonnies twin 255 pumps to a Aeromotive Boost reference FPR (ran a new fuel line, and used the old feed as the return now)
Wastgates: Twin Tial 44 mm.

The rest others can help you with. I have an auto. I know the S475 can be laggy if not properly set up, but people use them and have success.

Have you also thought about a cam?

Sarg

iTrader: (6)

Custom cam from liljohn will go a long way to aiding spool.

z28C4maro82z

iTrader: (33)

The custom cam will definitely be added to the mix!

Some good info there! I've been getting that itch....

Will the tial 44mm wastegate work well with a single not a twin setup?

Sarg

iTrader: (6)

Maybe, depending in boost levels. You could also get away with twin 38s.

jay_rich

iTrader: (8)

I would go with either a custom grind from liljohn or even something like the speedinc TU1 cam. LilJohn told me for that exact combo a cam with around 0-4 degree overlap is needed to get the S475 T6 1.10a/r movin with a 4.8L.

I was planning basically the same build with Twin 44mm's, Twin 255 pumps, 80lb injectors and the TU1 cam. I ended up picking up a 05 5.3L though so it changed a tad. Also just tossing on LS1 gaskets since the bore size is massive on LS9's.

Jay

Forcefed86

iTrader: (4)

Pump gas?
HP goal?

Sarg

iTrader: (6)

I went with the ls9 gaskets on my 5.3 which is the same bore size. No regrets and seem to be holding just fine.

z28C4maro82z

iTrader: (33)

Looking just run pump gas yes, and I was shooting 650-700 range. I would be happy sitting there and having it be "streetable"

Forcefed86

iTrader: (4)

You'll run into detonation on a 4.8 well before your goal with pump gas. Add a good methanol inj. kit to your list if you are going to attempt it. Do you have a ET/MPH goal for the drag strip? Or is this just a street toy. A true 700hp is pretty useless you weigh 2+ tons.

Buy injectors once, they are roughly the same price. Go with 80's. You'll always want more, go bigger if you can.

LS9 is a good gasket. You can also get a MLS felpro gasket that matches your bore size for less. Look on Ebay. Proven to over 35psi on a T88 5.3 with china head studs.

862 heads are fine.

Look up the slightly better walbro 450lph E85 pump. It flows more and is only slightly more expensive. Once you add boost to the equation and depending on your base pressure I doubt one of these will make it to a true 700+ whp.

I don't know much about clutches, but getting a manual trans to hold up to a true 700+hp will be pricey. I'd worry more about that than the clutch.

Turbo's ok. I run one and the back pressure is really high at 20+psi. I'd look at the billet 6 blade 75mm "race" comp. wheel. Go with a larger 87mm exh wheel coupled to a 1.25 AR T4. (just picked up mine for $900 shipped) Run a 2" hotside to each side of the scroll with combo matched cam as mentioned above. IMO this would spool faster and make more power with less back pressure than the turbo you had picked. Only costs slightly more.

z28C4maro82z

iTrader: (33)

Some awesome information right there.
Going to take some advice there

nasty64

Subscribed. Im doing a 4.8 single turbo in a 64 Bel Air. Need all the info I can get

z28C4maro82z

iTrader: (33)

Agreed I'd love to see some more insight here....looking to get some parts ordered soon and maybe have her ready by august

Forcefed86

iTrader: (4)

Best insight for a noob in all honesty... Leave it alone and put a turbo on it.

This thread shows what an unopened unmolested 4.8 is capable of with good fuel and a tune. This is an untouched, straight out of the yard 4.8. Valve springs should be your first upgrade.

https://ls1tech.com/forums/forced-in...float-now.html