RayRayObs956

Looking to achieve 500-550rwhp if possible. At the moment I have block at machine shop looking at what 408 rotating assemblies but don’t know which would be best for my application. I currently have L92 heads and a LY6 Intake i believe. I also have the Texas speed F-35 cam 235/248 .649 lift not sure if it’ll work well or if I need a bigger cam this is my first stroker so looking forward to getting some help. Was originally going to do 6.0 with ls3 top end but then thought about stroking it while I’m at it. Don’t know whether to build it with ls3 heads and intake and drive it as is, or sell Heads/Cam/Intake then buy Cathedral set up. Will be using truck 3-4 times a week originally was a daily driver. Motor will be going into a 98 Chevy Tahoe. Set up will be with a cathedral top end later in a couple months from now, looking forward to getting some TFS 245 cc heads along with a Holley hi rise intake. Haven’t decided yet on a cam. Truck will be running on e85 and I just got my converter restalled by circle d to 4000-4200. I currently have a 4l60e with 4.11s. I did however get some 4.56 gears I have not yet installed as well as some 90lb injectors and a pulley from summit. Also have a wet nitrous express kit. Don’t know it to keep it n/a or get a nitrous cam. Open to suggestions looking to spend less than 2800 for a good stroker rotating assembly if possible. Would appreciate the feedback thanks again. Was also wondering how much power you guys think I’ll put down if I do decide to use ls3 heads for now.

bortous

I got an LS 408 with LS3 heads.
I had a 236/244 .626 .626 114 LSA Camshaft and I made 505rwhp.
This was with a FAST 102mm intake and Nick Williams 102mm DBW throtte body, ported heads Yella terra rockers plus other supporting mods.
It is possible to make over 500rwhp but you would need a bigger camshaft.
Something like a 242/254 113LSA+4 will certainly get you over that power level but you will need at least 12:1 compression.
Trickflow heads you would need a larger camshaft to achieve the same goals but these heads will produce better low and mid range torque.
Bang for buck I would stick with LS3 heads.

lazerlemonta

Honestly if i was building a 408 to go into a Tahoe with no boost i would be more concerned with grunt the horsepower. The holly high ram would be the last intake i would consider using. With the weight of this thing, I would use one of the off the shelf truck cams that keeps the operating range as a truck should and give you nice torque early on. A 408 is not going to want to spin to 7600+ to take full advantage of the high ram. Your Tahoe will accelerate much quicker with a torque monster then a spin monster. Just an opinion. Good luck with your build.

spanks13

iTrader: (5)

Agreed! Don’t make a turd just for a dyno sheet

Darth_V8r

iTrader: (4)

Tfs245 a great choice. I would back off a bit on the cam. Something like 230/238. In a truck if you plan to tow you do not want much stall, 2800 tops, so the cam has to be more docile. Maybe even less like a 227/235. If you do not plan to tow or haul your stall is good. Run your compression around 11:1 and use good gas. Fast 92 or dorman ls2 would be great intakes. Run 1-7/8 headers, a good merge, and you should be in great shape.

99 Black Bird T/A

iTrader: (4)

Call Reher-Morrison and ask for Darin Morgan or call Mamo Motorsports and ask for Tony Mamo. Port your current LS3 heads and do a custom ground cam for your application. Talk with Darin or Tony about the intake selection, they probably suggest a Fast 92/102. Tony does killer porting of plastic intakes, I have one of Tony's Fast 102's for a 408 project.

Darin ported a set of LS3 heads for me and spec'd a sweet 237/245 custom cam for my 416 and suggested a Fast 102 with the runners cleaned up. Due to budget I used LS3 rockers and LS7 lifters and kept the list down to ~.625. You can be more aggressive than I was with more lift with a set of Morel or Johnson lifters and your Yella Terra rockers. The engine makes massive low end torque perfect for a truck. Hits 400+ rear wheel torque at ~2,800 rpm Peak numbers were 517 whp & 471 wtq through a T56 Magnum& Hawks 8.8 reared with 4.10's.

I think you can get very close to 500whp and maybe break 500whp+ and have massive low end torque with very good part selection by porting the current LS3 heads, with a better cam, and better matched intake manifold. However for the best chance at doing it it would be worth contacting Darin Morgan at Reher- Morrison or Tony Mamo of Mamo Motorsports.

Regarding stroker rotating assemblies, I have a 383 LS1 and 416 LSA, with used Callies CompStar crank, Callies CompStar rods and Wiesco's stroker specific pistons. Very happy with the parts neither engine is an oil burner. Piston material selection can help too, 4032 will be quiet, wear better and last longer in NA use. The 2618 material is typically better for hard performance and spray but looser fitting and less durable in normal use. For my 408 build, I picked up another Callies crank and plan to get Callies rods and Wiseco pistons again

K1 also makes excellent cranks but I havexran a motor done with K1 parts yet. K1 with Wiseco pistons would be my other top choice. K1 & Callies with Wiseco normally fit with little need for clearance work sometimes none. Molnar has a great reputation and is a another one worth considering. Likewise Manley but Manley will approach $2,800 very quickly. The others should be under $2,400 pretty easily. Others may suggest Lunati, Scat or Eagle.

Some of the big sponsors can basically include a "free" balance of the rotating assembly with a Callies crank. You'll want to call around to explore the details. In any case you can in under $2,800


I think the Holley intake is probably the wrong intake unless this is a race truck. If it is a race truck, 5,000+ stall may work better with the Holley and might be worth researching.

lazerlemonta

I dont think I have ever seen 2 names mentioned so many times in a post lol

99 Black Bird T/A

iTrader: (4)

Callies and K1 or Darin and Tony ?

Gotta give Smokey a little competition on the name dropping now and then

Wink

bortous

Good advice.
If you port LS3 heads though, does it make them feel lazier in the low end?
Does the runner become 280CC?

lazerlemonta

My CNC LS3 heads are 281cc and my low end is not lazy at all. I have a 3200 pound c6 with 4.10s to help that situation.

gnx7

iTrader: (28)

I built an 11:1 91 octane 416 for a customer using stock LS3 heads/intake and a BTR cam which made 560rwhp on a Dynojet thru a T56 Magnum and 335/30/18's out back thru dual 2.5" exhaust and 1 3/4" headers. He is now going with ported heads and Rick Crawford ported/radius rod LS3 intake and running dual 3". Shooting for 600rwhp on 91 octane.

lazerlemonta

That intake will be what keeps him from achieving the 600. Im at 562RWHP with a SBE LS3 using stock ported heads and SS4 fly cut cam with supporting mods. It just does not have the plenum volume nor the capability of putting a 102tb on it with out some porting and epoxy. What vehicle is this motor in? GPI just did a nice intake comparison test showing gains on a SBE LS3 that would be worth looking at for him prior to purchasing that intake. It will run out of steam around 64-6600 and plateau would be my guess.

99 Black Bird T/A

iTrader: (4)

Depends entirely on who is porting and if they know what they are doing for your application. Correctly matching the cam to the ported head is also part of getting crisp response. Likewise, compression increase helps with excellent throttle response.

It's been a couple of years I can't recall the exact cc 277? but Darin Morgan's Ls3 runner stays less than 280cc. Only a couple of cc's are removed and the heads pick up a lot of flow.

My 416 is more responsive to throttle than a stock LS3 Of course going speed density would enhance the responsiveness even more.

Smokey B

Wink,Wink..
Original port by Darin was under 270. Think 265 cc

Smokey B

You can get around a larger port with good camming.

SAPPER

iTrader: (10)

Based on the dynojet I was on, My sons car made 500/487 NA with a basic tune with a 10.8:1 CR & 93 gas. This was with Cathedral port heads, stock valves, stock chambers- not milled. Granted I ported the heads myself and have been doing heads for many years. But with the right combination and little things, 500+ is easy. But Hp is in the heads.

Also I have a vid of my son running side by side with a supercharged C5 Zo6 on 12 psi who's dyno showed 620. But its on my phone. So our true numbers aren't really known. But the car runs very strong.

Tuskyz28

RayRayObs956

I plan on slapping on a turbo eventually possibly late next year. I agree with what your saying torque would definitely benefit my tank of a truck lol. Spikes performance recommended the hi rise intake, I wouldn’t know which other one to pick out.

RayRayObs956

Appreciate all the information brother I’ll definitely be giving them a call to see how much to port my heads and see what they recommend. Was thinking of a BTR cam but haven’t decided yet. Was however going to get some Johnson lifters and springs .685 lift. Any good other intake manifolds you know is good for my truck application? I’m going to look around at the rotating assembly parts from the different brands you listed. And that motor is pretty damn impressive making 400+ Torque at 2800 rpms?!?!

RayRayObs956

Thanks for the feedback everyone, really appreciate all the help. My 98 tahoe will be a full on race truck. This past year truck hit a 12.9 on motor and a 12.3 on a 100 shot with a lighter driver. This was with the old 317s. Had some Mickey Thompsons 275/60/r15 to help with traction. Truck was really responsive in the streets. I would street race a lot and people couldn’t believe how strong my truck was. **** if anything I was more shocked myself. Definitely will consider porting the ls3 heads and intake for now. I only know of 1 person who can do the job here around the area but he isn’t all that great anymore. Spikes performance is who spec the Holley hi rise intake, but if you guys don’t think it’s worth getting then I’ll consider a different intake manifold. From what I read you guys think I should stay with my rectangular port set up instead of going back to a cathedral. I also have the 4.56 gears to help move this heavy tank. Was originally told to get a Eagle Rotating Assembly or a TSP, looking at a balanced CompStar 11.4:1 kit would this be good?
Description says this

GM GEN III GEN IV 6.0L 408 Stroker Rotating Assembly, Callies Compstar Forged Steel Crankshaft 4.000 Stroke, Callies Compstar H-Beam Rods 6.125 , Mahle Forged Flat Top Pistons -4cc, Balanced Rotating Assembly

This kit is designed for performance application builds up to 1200 horsepower. This stroker kit offers upgraded ARP rod bolts, heavy duty wrist pins and gas nitrided steel piston rings to support nitrous, blowers, turbos and supercharger applications. Kit fits GEN III 6.0L Vortec 6000, LQ4 LQ9, GEN IV 6.0L LS2 L76 L98 L77 LY6 L96

GM 6.0L Rotating assembly kit

• Callies Compstar 4340 forged steel ls crankshaft 4.000 stroke
• Callies Compstar forged 4340 steel H-Beam rods with 7/16" ARP 2000 rod bolts
• Mahle forged flat top pistons (-4cc) with performance piston ring set
• Premium H series rod bearings and main bearings.
• This stroker kit has been Internal balanced in house by CNC-Motorsports
• Compression Ratio with 66cc 11.4:1