Hey everyone,
New to the board, relatively new to the LS platform, have built SBCs in the past. I purchased a 2003 Silverado HD2500 2WD with a 6.0/4L80e. My plan is to rebuild for a 1957 Chevy project, aftermarket frame, C4 suspension. This is really going to be a weekend show car but I do intend on driving it long distances (say couple hundred miles per trip). I'd love to say I'm going to autocross/strip but it'll never happen. Said that with my Chevelle when building it and it's never seen the strip.
OK with all of that in mind, here is my thoughts on a build:
1. Don't touch pistons, rods, or crank. I pulled #3 main cap and the bearings looked fine.
2. Replace oil pan/pickup, oil pump, rear main seal and plate, water pump.
2. Replace cam (factory), heads (317), intake (stock truck).
Heads - Thinking of sticking with Cathedral ports like 241s, no porting, upgrade springs (with Cam). The thought here is to keep the compression at or below 10.0:1. I'm in Iowa, so we can get 91 Octane with or without 10% ethanol and occasionally 93Oct with 10% blend (this is rare). I absolutely want to be able to use pump gas available locally.
Intake - I really like the sheetmetal intakes available. Seems like they are all the same, except maybe the Holley hi rams? Since it's a 57, hood clearance is not an issue at all. It needs to look good and perform.
Cam - Here is where I get lost fast. There are dozens of companies with dozens of cams out there. I'd like a choppy idle (who doesn't love this), but since this is going to be a heavy car, I'd rather sacrifice chop for low end. I'm not building for high HP in the 6500 range. I certainly plan to call a cam company and get a recommendation. Maybe looking for some real world experience and a place to start from this group.
What would you recommend? What am I missing OR would you do different? 241s a bad idea?
Advice welcome and appreciated.

 

Heads are fine. Leave em. If you just MUST, get ones off of a later motor in the 06-10 range, look for casting #s 243 or 799.

EFFFFF a "choppy idle". It's 2024. Either you wanna have an engine that makes good power and pushes a car hard, or you want ... that other. Unless you're planning on participating in the "square inches of krome" contests down at the local grocery store parking lot on Friday nights, EFFFF abuncha "chop". I'd suggest one of the "Stage 2 truck" cams from any number of vendors; they're all something around 212°/218° @ .050", w/ as much lift as you're willing to buy valve train for. You can use one of the "low lift" ones (around .550") and leave 1 or 2 horsepuckers on the table butt not have to go crazy on valve springs and whatnot. Look at TSP, Summit, Vinci, CamMotion, and so on.

The LQ4 intake is quite good. Again, unless you're into "looks" (see above about parking-lot bishop-buffing), there is absolutely nothing whatsoever to gain with a sheet metal one. There's no "there" there. Only way that will make the car faster is by way of SERIOUS weight reduction, concentrated at the driver's wallet. Get a snazzy cover instead.

 

A big cam and the short runner sheet metal intake makes for no bottom end power.....
You can get a decent chop with a truck cam close to 220 deg duration like mentioned above with a "chop tune" and still have tone of low end torque, I would run a dual plane carb intake with a holley sniper before I would even think about running a sheet metal one.

 

I’d pull apart your stock oil pump and look at it. measure clearances. Its likely fine. I’d simply leave the 317 heads. Mill them if you really want more compression. Unless you have some 241’s available for peanuts… I wouldn’t bother switching. Honestly its pretty typical to use the small valve 706 heads. They will give you a healthy bump and if you choose a decent cam with overlap to bleed off come compression, and tune responsibly, they are still pump gas friendly.

Sheet metal intakes for a mild build work horribly. IF you aren’t going to rev the motor out quite a bit, most want the long runner TBSS gen4 style truck intake. Other wise you’ll be giving up 20hp and 30ftlb+ from about 2k to 5500. Its really that bad! The LSXR intake is the only comparable intake and its boku bucks. Not worth the money IMO when a factory intake does darn near the same thing.

Everyone will have a different cam opinion. Truth is you are splitting hairs in most cases. Talking 10-20hp difference in most cases between the typical 6.0 mild NA cams. You just trade low end for top end the “bigger” you go in most cases cam wise. The summit cams can usually be had for a great price. Something like the “sloppy stage II” is great for a budget cam. Just depends on your budget.

 

Thanks for all of the responses guys. I really didn't consider that an aftermarket intake like would ruin the power curve. I mean in looking at various Youtube videos and specs of intakes online, it seems to me like they are sold as the "any Joe" manifold. Anyway, I had been looking at Sloppy stage 2 cams, but I really wanted an unbiased opinion. So thank you all, I will start in the Stage 2 realm and start calling cam companies.
Regarding heads, I had thought about milling the 317s, however I assumed that would cost more than finding a pair of used takeoffs. The few people I have talked to turn their nose up at 317s, I took the queues. Everyone has an opinion, and it's a wide spectrum.

Next topic: let's say I jump to Gen IV TBSS intake or any other intake other than GEN III stock truck, would you keep the DBW TB? I bought the whole truck, so I have the gas pedal, TB, and module along with the wiring. What would you do?

 

I have had more issues with IAC valves on cable throttle bodies than any throttle by wire throttle body. With that said..... I still run cable throttle bodies in all my swaps lol.
I don't know how handy you are but a shaved Tbss/gen4 or gen 3 truck intake look pretty clean, especially painted.

 

Look at the famous "intake manifold shoot out" Holdner did. Its all over google. You can see exactly what you lose going with a short runner intake VS the OEM TBSS style “ugly bread box” intake. If it fits, it really is a great manifold.

I wouldn’t sweat the cam choice either. When looking at most “Stage 2” sheld cams you are prob within 5-10hp of each other w slightly different RPM curves. They’d prob all run with 1-2mph of each other at the track.

Similar to the cams, the only difference between a 317 and a 243 is the CC size. Pill a 317 down to a 64cc chamber and you have a 243 (w a slightly thinner deck). Used take off 799/243’s are usually $400-500. Def not worth that IMO. You can pick up a set of small valve 706 heads for $100 or less usually. They have a 61cc chamber and will make more power than any of the other heads from the comp. bump. So milling what you have or sourcing a set of those is prob the way to go.

DBW is nice if you have an ECU that can drive it. If you are using the stock ECU and plan to keep it. I’d use DBW. You have larger TB’s to work with and the JY is full of them if you need another cheap.