1hotvega

I decided to do an LS swap on my shop truck (A 1965 Chevy shortbed). Looking for some build advice for a daily driver that I use as a truck I tow both my boat and travel trailer with it. So far I have bought a complete 2004 5.3 and 4L60 fan to tails haft and also a 2003 6.0 LQ4 truck engine. The 6.0 is just a long block so I plan to use all of the external components from the 5.3 to complete it. Lastly I own a machine shop so the cost of any machine work is nil.

Short block- I had planned to bore it and install flat top pistons to get the compression up with the 317 heads. Aside from basic rebuild items is there anything special I need to know? A friend of mine has a new set of Weisco 408 dished pistons he ended up not using that he would sell me. Is it worth it to build a mild 408 for the street?

Heads- I had planned on porting the 317 heads. I have access to a superflow SF-750, but was unsure if I should upgrade to the rectangle port heads and intake from a 6.2. I was looking on Ebay and the heads and intakes are available pretty reasonable.

Intake- Can someone explain if the 07 and newer truck intake is the same or close to the design of the trailblazer SS intake I read about? I have lots of hood clearance so I was intending on using the truck intake manifold.

Camshaft- This one was kinda of a biggie. I had originally thought of using a GM Hot Cam but then read about some grinds from Crane Cams designed for trucks that gave a really nice mid range boost in power with no loss in low end torque. Ideally I would perfer to use a GM, Isky or Crane Cam.

Exhaust- Was planning on using some long tube swap headers. 1 3/4 or 1 7/8 primary.

My goal is 400-450 wheel horsepower and daily driveable, I would sacrifice horsepower for driveability.
I primarily rebuild engines from turn of the century through the early 1970's This is the first LS engine that I have ever had in my shop, any advice is appreciated. Thanks JEff

Mercier

iTrader: (15)

Does the engine need machine work? I know you say it is free but it is time, too. A stroker 408 is great on the street if the parts cost doesn't bother you but a 6.0 with under 130K miles I would just run it. Your RWHP goals are reasonable. The rectangle port heads will fit a stock 6.0(4") bore and make great power but if you want to keep your towing torque, you either need to stick with cathedral port heads or cam it just right. Kip @ Cam Motion is who I would call; I just had this exact conversation with him. Not for a tow vehicle but still for a 4,000lb Caddy. He has all the old-school experience but keeps up with the newer technology and grinds boatloads of LS and older platform cams in-house for the same price as the other guys with better quality materials.

Is your donor drive by wire or cable("DBW, DBC")? The TBSS and NNBS intakes are basically the same thing and cathedral port. You get more flow potential compared to the older intakes your donor engines have/came with but you also move to a 4-bolt throttle body(90mm opening). This isn't problematic but you will have to source a throttle body(readily available). You can get a new bare intake om Amazon.com for about $115 here:

http://www.amazon.com/gp/aw/d/B004JB...-zL&ref=plSrch

But I'd call Kip first and ask him what he thinks about 6.0 with LS3/L92 heads in a light-medium-duty tow application like yours. If you decide this route, you'd need a L92 intake. Those are similar to above but with the right ports to match the heads. Can be had cheaply as well and also flow great when you have the hood clearance.

If you don't go L92/LS3 heads, I'd sell the 317s to someone that wants that big chamber for a FI build and get yourself some 243s or 799s. smaller chamber and better port design; basically the factory "hot rod" LS head.

JoeNova

Swap out the 317s for some 243 or 799 heads. Higher compression, slightly better flow. If you're going to port heads, the 5.3 heads offer even more compression, and if you port them you can easily get flow numbers better than the 243/799 heads. Rectange heads flow a lot more, but make less torque below ~4500 or so RPM.

The newer style truck intake bolts right on. You'll need a larger throttle body, the 90mm ebay ones work good.

BTR stage 2 truck cam sounds good, and doesn't sacrifice torque for power. You get nice gains across the board.

1hotvega

I couldn't trust the engine. It came out of a GMC 3500 Box van at the pull it yourself wrecking yard, probably has a bazillion miles on it. Turns free and there is no water in the oil, the $280 price made it an irresistible deal to me. Originally I was going to build the 5.3. I have a 4.00 stroke Procomp cast LS stroker crankshaft I bought about 2 years ago. I had planned on using it in the 5.3 and boring it to 3.898.

The harness I plan on using is a throttle by wire. Will the 07+ truck throttle body work OK? Are they larger then the earlier ones?

I have read a little about using 5.3 heads on the 6.0's. I think my 5.3 has 862 heads on it. I had planned on using flat top pistons and that would put my compression into the 11's. Really didn't want to run it that high and thats why I had planned on using the 317's. Is anybody out there with small chamber heads and flat tops? Would like to know how it runs out with pump gas and a mild cam.

Mercier

iTrader: (15)

Running 11.x:1 on pump gas is perfectly doable with a proper tune with the LS. Now if you want to make power with 87 octane, probably not the best route to go. The 862s do have a smaller intake valve but can be cut to a 2" valve such as the stock LS(and those 317s) head uses without changing the seat. Even if 862 is too high, I think 317 may be too low. Have you calculated where CR would be with those and the pistons you mentioned?

I am not 100% sure on compatibility of the later DBW throttle body with the earlier harness. The later, 4-bolt TBs are larger; the intake opening is about 90mm whereas the gen III/earlier trick intakes I believe are about 85. The later intake flows better as well.

HCI2000SS

iTrader: (2)

I run 862's with flat tops on my on my 6.0. Compression is 11.5:1 and I have no issues running 93 octane