moes04silverado

iTrader: (2)

Guys(gals is any) As some know I scattered the **** out of my 6.0L a few weeks ago, and at first I was like f-it Im not doing anything until the winter. Well its nice as hell out and I am going f-ing crazy not having my truck to drive. So last night I was reseaching a little and came up with three different plans.

No. 1 Take the 4.8 and bore/build a 383 (which i kind of know what parts are needed from researching)

No. 2 Take the 4.8 and bore/build a 370 (which I have no idea how to obtain)

No. 3 Which is not really my personal favorite option - but get a new Lq4 and try it again....

Personally after looking at parts and taking with my buddy that works at Weisco, I am leaning to the 383 (and I like the torque from a 383). As for power additives, I highly doubt I would ever add a turbo or charger, but it is possible maybe for some nitro down the line - nothing crazy though.

So the floor is open for suggestions....Thanks Moe

ricoc

stock 4.8 bottom, bored to 4.00" = 327 @ 7000rpm with 4.56 gears

InchUp

iTrader: (2)

Not enough room for 4", but bored out to 3.898" like your average LS1 would make for a 312 cubic inch motor. I'm not sure if anyone makes aftermarket pistons for the bored-over 4.8L though, considering the 4.8L uses the long rods. I took my 5.3L to 3.898" and at first my machine shop was hesitant to even do such a thing but eventually it got done. My #2 and #6 cylinders are at absolute minimal wall thickness of .125" thick. I couldn't imagine boring over any more while still keeping structural integrity, especially at 7000 rpm.

I like the idea of the 383 the most. I'd bore the 4.8L block to 99mm so you can use stock 3.898" LS1/LS6 pistons when purchasing the stroker 4" crankshaft. With that you'll have a 382 cubic inch motor, 6.26L. Full rotating assemblies are fairly common to find, just read through a few LS1 threads from the car guys to see which kit is the most popular and dependable. A high RPM screamer would be cool...but not for street use. Maybe for a certain racing class under 5.1L or something to that degree. The big bore 4.8L would certainly require outrageous gears, a very high stall converter, a very radical camshaft and stiff springs and nothing would last long due to all the excessive high RPM friction and wear. Gas consumption would sore considering the motor wouldn't make power below 3500-4000 and overall life of your investment would be cut considerably.

Believe me when I say I am not one of those guys who is so fixed on "there's no replacement for displacement", I love my supercharged 2.4L 4-banger in my daily driver and I see the use for small displacement motors in everything I do. I just don't see this particular application being well off with anything less than a 5.3L since you're trying to make power equivalent to your 6.0L. The 382 would most definitely take the bull by the horns and lay rubber for 3 gears. A high RPM screamer just isn't suitable for a heavy truck.

LMSeven

iTrader: (3)

I say bore to stock LS1 size (3.898) and get a stock 5.3/6.0/LS1 crank. Get some stock LS1 sized forged pistons & rods, then call it a day. If thats not enough, L92 heads/intake. With that you could spray the house down. I couldn't justify the price of a forged crank when stockers go a long way.

Inchup I believe there's a few people on here with 5.3's bored to 5.7 with forged rods/pistons and making good power that is safe on the iron block. I'm pretty sure thats Blownchevy's set up, and he's packing a TVS 1900 blower

InchUp

iTrader: (2)

Oh, I hear you loud and clear. Like I mentioned before, I did the 5.3L to 5.7L build on my own and that's the motor going into my lifted Sonoma project truck. I know it's still strong enough for anything I'll put it through for sure. I'm not sure, however, on how strong it'll be if one starts boring over any more than the stock LS1 99mm bore. I was addressing ricoc's comment of a 4" bore, which leaves the block without cylinder walls...he'd be right in the water jackets. Yikes!

moes04silverado

iTrader: (2)

well my thought with the stock ls piston size and a 4" crank seems like the most suitable way to go right now - there is always room to bore to 3.903 or 3.905 in the future if it gets worn out. The 4" crank i found is a 4340 forged crank and is only $970. I can get "off the shelf" pistons from Weisco for a decent price being that my buddy works there. As for a cam - I have TR224 right now that was in the 6L but I am unsure right now if its ok after the blown motor - the 6L was tore up pretty bad so I dont know if it damaged the crank or not.

So with the stock size ls piston and a 4" crank, what size rods go with that combo 3.622 or 3.600?

InchUp

iTrader: (2)

3.xxx what???? The stock rod is like 6.098" if memory serves. Whoever makes that stroker crankshaft should have a recommendation, if not the entire rotating assembly. Call up a company and ask about their kits, that's why I mentioned snooping around on LS1tech for LS1 stroker kits and who has a reputable company name.

LMSeven

iTrader: (3)

You can buy 6.0l's for the price of that crank.

I'd really like to do the 5.3 to 5.7 build whenever this thing needs a rebuild, but I'm kind of undecided on skipping that and going with a LQ4. Haven't really worked any numbers yet because it's not an issue

InchUp

iTrader: (2)

I'll let ya know how mine turns out then. So far it's looking good.

moes04silverado

iTrader: (2)

yeah that is what i meant - give me a break it was past 11pm (two hours past my bedtime) so i was half asleep!!!

So how is a 370 achieved from the 4.8 block? I think i want to start with that....