Well, based on the large success with big bore short stroke engines we have had, I'm building one for my car.

6.0 block that's been sonic checked and cleared for 4.128 bore
Stock crank
Scat pro comp I beams 6.100
Sb2.2 flattop Pistons from Bill Miller Engineering
king bearings .0026 Rod and .0025 main clearances
Btr slr lifters

These are the givens that I've already got.

Now for the area of like advice on.

I'm wanting to run ls3 heads with the l92 intake I already have.
Going to have FTI or Martin do me a custom grind

I had good luck with my 6.0 with ls3 heads at 454/425, but what top end would you guys like to see? I feel this big bore the ls3 stuff would shine.

Car is the one in my sig, 70ss nova
5,500 stall
Th400
4:11
315/60/15's
3000# race weight

 

With that big of a bore, I would want LS7 heads but I don't think the engine is big enough for them. Maybe something smaller, like the RHS small bore heads. LS3 heads would work fine too.

Out of curiousity, where were the cylinders checked and what did they measure? From what I've seen, there's plenty of meat at the minor/major thrust areas but between the cylinders is where it gets thin.

Also, why SB2.2 pistons? Aren'the the valve reliefs diffeent?

 

As for heads, if you want to use ls3 vs ls7 heads, then I would start with the cnc ls9 heads for like ~$1800. Thick deck, good valves, excellent value. Have someone who is good at what they do give the heads a little extra love, and you're good to go.

I am quite interested in this build of yours. The 3.62" stroke 388 is something that I, personally, think should be awesome. I'm actually surprised that the combination isn't more popular than it is.

Give some serious thought to a low lash solid roller cam, and possibly a vacuum pump. With a 5500 stall, this is going to be a screamer.

 

I agree, I considered ls7 heads but I think I would have to wind the **** out of it to get it to be usable, no? The ls3 I think would be a more usable piece, would like stay around 7,500 max.
I'll post up the actual sonic results after I get the block, I can't remember off the top of my head and o don't want to mislead.

I'm using the sb2.2 Pistons for a variety of reasons, #1 they will work with stock rods or in my case allowed me to get a set of the scat rods which appear to be a very nice piece for very cheap, literally half price of most other rods. #2 these are a true flattop so the relief is a non issue, although I talked to my machinist about it aswell as a few other locals and they said as long as ptv is adequate it wouldn't have mattered of the intake valve relief was incorrect. And number three they were $150 with ultra light pins lol, I'm on a very tight budget to get this done.

 

Glad you're as enthused as I am! I was expecting the typical flack about "you can't bore more than .030 !! " that I normally see lol.

I stumbled across a thread last night were a magazine had done this exact thing, except destroked an ls7, used a solid cam and ls7 heads, and got over 620hp that was built for a road race car with the intention of toning it down but getting some big RPM's. I've already got lifters, so atm I'm going with a hydraulic but a solid roller is in my mind and a big want.

 

Yeah, I think the cnc ls9 heads are exactly what you're looking for.

You said 7500rpms, max. Which is smart on a stock crank. When you do decide to pull the trigger on a llsr cam, you should invest in a forged crank, and dry sump oiling (if it's at all possible on your budget), and raise that redline... Then you can start shifting at 7500rpms!

 

Stock crank get iffy past 7,500, or is it a. Oiling issue? I was wanted big to shift around 72-7400 on this combo, dry sump ect are all things that I want but bits going to be worked on down the road, this freaking 4l80e converter is going to cost more than my engine lol

 

I'd highly recommend the Dart LS3 "as cast" heads. I've been blown away by the power they have been putting out, and I sell them assembled and ready to go for 2500.00 bucks.

That includes a dual spring kit and stainless steel valves.

 

Cast parts, in general, reach their natural frequencies sooner than forged components. After you start approaching 8000rpms, it's nobody's fault but your own if a cast crank literally just falls apart.

And, right around 8k is where you really start finding the limits of the LSx wet sump oiling system. Crankcase windage gets pretty extreme at those rpms, and the ability to maintain oil pressure at the top end of the engine becomes more and more difficult. Piston rings flutter and let oil into the combustion chamber, and allow blow by from the combustion chamber into the crankcase. None of this is conducive to creating power or reliability.

There are exceptions to every rule, and I'm sure you could find a whole host of examples of stock crank LSx motors spinning close to 8k with wet sump oiling... But, if it was my money, I'd opt to avoid those rpms until I knew my engine was built for it.

Not to over simplify anything, but usually high rpms coincide with high speeds, and high speeds are not where you want to be when you exceed the limitations of your cast crank or wet sump oiling system.

 

looks like a cool build, but I have to ask what happened to the 505 in your sig? Im guessing that made some good power with those heads.

 

That's a pretty good price, unfortunately I'm on the used stuff budget. The $6-700 used ls3 heads are about all I can cough up at this time. I'd love to try them but it's just not in the budget. Down the road I may try those and a solid roller setup.

Good to know! I'll keep it around 7,000 then!

 

Actually, the machine work was finished last week and the same day my cummins decided it didn't like the trans. So I was forced to sell the 505 and I'm putting together this 6.0 with what's left over :/

 

^^^^^^sucks when you have to keep the dd going. The diesel trans seem to be expensive too. Good luck with the build and trans

 

Yup, costing me aboutv$4,000, it sucks. The worst part is why. It lost the front input seal and tosses all the fluid out down the interstate :/ locked it up. Thanks for the good wishes! Rods showed up last night