stone150

iTrader: (2)

I would like to Swap in an LSX into my 2001 Silverado 4X4 and start gathering parts this summer. I was originally looking at a 454 N/A, but now I think that after a year or so of the N/A setup I will go S/C or turbo. I would like to go ~ 10.5:1-11:1 CR as to run pump gas.
If I do go FI, would I need to change the pistons out when I go FI to lower the CR?
I would like to get 500-600 hp in a N/A state, but if I plan to go FI down the road, would a 376-427 be better? (thicker walls, lighter rotating assembly)
Can I make that kind of power with gen III heads and intake (cathedral port)?
I would like to stay as close to "stock" looking as possible.

Will I need to go to the LS2 style knock sensors for the LSX block?

Thanks!

redtan

iTrader: (5)

If you get flat tops now with relatively high compression ratio, you can always get some bigger chamber heads like a 317 to lower the compression when going forced induction.

The thing with making that much power NA today and then wanting to throw boost at it later is that you're going to have to change a lot of things like cam, heads etc. A cam that makes close to 600rwhp NA is going to stink for a turbo or supercharger. The same with the heads, you're going to want to lower compression.

Also, depending on your power goals with FI you might want to stay with a smaller cubed motor just for reliability sake. Although if it's an LSX block it should be able to handle quite a bit of power whether you go 376 or 454. It's all in the final goals powerwise. You can make 1000+rwhp on 376 cubes with the right setup and FI.

stone150

iTrader: (2)

I figured I would have to change some things like the cam, but I am trying to keep the changes and mainly the cost to a minimum when the change happens. I figure Pistons, while a harder change, requiring pulling the engine, would be a cheaper proposition.

The block would be a LSX, if I do a 454, I will just get the 454 Block, other wise I will buy the standard one and have it machined.

This project is 2 fold for me, 1st part is to have the sport truck I always wanted, the 2nd part is to go through the engine building and planning process.

While I would like to gen III heads, and I would look for the best flowing heads I could I would try to pair it with the truck manifold I already have. But I do realize that would probably limit my power and the last thing I want to to have a big displacement engine that is a turd for power.

As I understand it I could get better flow out of CNC'd LS3/L92 or CNC LS7 heads and that would mean I would need to run a gen IV intake, I was looking at a FAST LSX or stock LS7 since I can still run a cable driven throttle body. Am I making the right assumptions?

If I run GEN IV heads and intake do they make the adapters to fit my stock sensor pigtails or sensors themselves?

Could I run a Gen III cam sensor or would I need to run the Gen IV with the Katech adapter?

86Z28USAF

iTrader: (1)

honestly i would go one or the other like he said its alot to change going from high power n/a to boosting personally i think its a waste of time and money. So i would decide now what you would rather have

Blackpanther99

iTrader: (8)

Agreed^ if your planning on boosting then might as well do it now. Changing cams, pistons, heads and other parts could be more expensive than just going to
boost now. Thats just my point of view because I went through the same situation. I was first planing in going NA on my build, but I wanted the more HP out of my block soo I said "what the heck!" Soo I went with boost in my build, I knew I was gonna spend around the same money going NA and going boost later than just going boost now If its your cruising truck or weekend toy I would do boost and get more HP out of the block you choose. I love the LSX427 for boost, really great block.

Havent had experiences with the 454 but its hell of a good block from what ive heard from other people and my tuner/ engine builder.

6D9 Matt

Yeah I would try and decide now... kinda what I have been doing the past few months.

I decided Im going to boosted in a year, so basically Im going to run a low compression 416 (Im thinking) set up for boost (except for the cam) and then in a year I will install the blower and new cam and be done with it (among maybe a few other small things, but nothing like swapping pistons, heads, etc to lower the compression).

stone150

iTrader: (2)

Well I appreciate the honesty! I was really thinking Twin Turbo, but after looking at other builds, and looking at what I want to do with the truck, I think a LS9 or TVS 2300 would get me where I want to be. Originally I wanted 1K hp but I don't know if I will ever use it, so 700-800 S/C would be where I want to be.

What Compression ratios would I need for a S/C motor vs. a Turbo Motor?

Would you plan to use LSX-LS7 style, LS3/L92, or LS6 Style heads?

CAMSTER

iTrader: (10)

If 7 or 800 HP is what your are talking about you will need thick decks heads or at list LSA or LS9 heads to keep you from changing head gaskets every month, i prefer 3/4 thick deck heads with 6 bolts per cylinder and a lq4 or lq9 block, you see the 6 bolts per cylinder heads, cost the same as the 4 bolts heads "but" are reinforced between head bolts by the extra bolt casting and that is the critical area where the heads lift between bolts to create gasket leaks.
Getting the proper hardware for the job starts with the core pieces, if this is done wrong nothing else matters, as the engine will only be as strong as its weakest link.
Then the connecting rods, these should be at list 100 hp rated over your max goal HP to be sure your investment don't go south on you.
Then there will be donkeys rears in the forum coming in to to critic this post over stuff you didn't ask, but they will be just that.

stone150

iTrader: (2)

Thanks!
Would you prefer the LS9 heads
https://sdparts.com/details/gm-perfo...parts/19213963

Or the LSX-LS7 Heads?
https://sdparts.com/details/gm-perfo...parts/19201806

Which seems to be build for applications that you are talking about.

My main concern with the LS7 style heads, is the guides, I know the production ones have been known to have issues and when my LS7 heads are out of warranty I will probably have them re-worked. Also It may limit the number of blower manifolds.

Honestly, I will welcome the questions, if it helps build a stronger motor and see options or things I haven't thought about, then I will listen as long as they provide solutions. I know general theories on engines, but part of the this exercise is learning all the engineering/theory I haven't learned.

Like the connecting rods, I probably would have done that anyways, but it is nice to have a starting point.

CAMSTER

iTrader: (10)

If you go with lsx cast iron block, for the money there's no better foundation.

As for the heads if the price listed is per head, i wil preferer to go with Texas speed item# 199-PRCLS36B255 for ls3 or item# 199-265LS7 for ls7 lsx block.
They have smaller intake ports and flow more than will the ls9 after ported have thicker decks, 6 bolts per cylinder and in my opinion stronger valves, i will make sure that they include hollow stem intake valves even if cost extra. They have two options a 60c and 69 cc combustion chambers, to be totaly honest to you, if you go with a 427ci or better yet 440 using these heads i don't see a need for force induction, with 11.ish compression ratio, to send that truck down the 1/4 in the 11 secs ets.
Check out Mast performance P/N 510-307 for the large bore block

You will need forge pistons.

stone150

iTrader: (2)

Thanks again!
Yeah I am starting to re-think the Forced induction thing, just because of the added cost of the blower. I won't rule it out in the future, but for what I want, I think I can get there with N/A. I have noticed there are little options in the way of 4.185 Pistons, I guess full custom is a possible option. Do you know anything about the LSX 454 rotating assembly fro GMPP?

But I do see allot more options with 4.125 pistons.

If i were to run a LS7 intake and fuel rails, do I still need a pressure regulator?

214Chevelle

I'm with you brother. I want to go supercharged with my Chevelle. I want an RHS 427 with a Kenne Bell 3.6. But, about time I figured everything up, I'm at $20k plus. So, I'm rethinking it too. It's really expensive. What I might do to save a little money is buy Chevy's LSX-376 boosted long block set up for 15 lbs of boost and then buy the supercharger. Alot of people rag on the powdered rods that come in the LSX-376 blocks. I laugh at that because everyone loves the ZL1, LSA and LS9, but they have the same powdered rods in those blocks. So, that clearly tells me that they don't know what they're talking about. They just be riding the ZL1, LSA and LS9 . LOL!! They all have the same internals....LSX-376, LSA, LS9 and ZL1. Check into the LSX-376 long block. You get everything for about $8K. All you will need is your supercharger, oil pan and rotating assembly. Lastly, if you go this route, be careful and make sure you get the B15 version. "B15" stands for boost 15. That's the newer version. GM sells an older version called B8 (8 Lbs of boost) that's cheaper, but only handles 8 lbs of boost. 8 lbs is not enough boost to make power in my opinion. But, the B8 version only costs about $6k.

Check this link out......
http://www.crateenginedepot.com/LSX3...50811C556.aspx

lazaris

iTrader: (5)

In that link its says the LSX376 has forged rods. Or are they powdered rods?

214Chevelle

Don't know what that's about, but the rods are powdered. Take a look at this from GM.....
http://www.chevroletperformance.com/lsx/index.jsp

motion427

iTrader: (1)

LSX376 part # 19171049 and LSX376 #19299306.
In my book,they are showing as the same rods,but the second part # has the forged crank and 6 bolt heads.

lazaris

iTrader: (5)

Im not so sure. That might be the old version for 8psi.
The new B15 version says: "New! forged internals and 6-bolt LSX heads that support more boost!"
"For builders who want to stretch the performance of a turbocharged or supercharged combination, we’ve got just the foundation you need:
Chevrolet Performance’s new LSX376-B15, featuring a durable, allforged rotating assembly to handle up to 15 pounds of boost."

214Chevelle

Exactly!!

Trust me Laz, B15 has powdered rods. Look here....
http://paceperformance.com/i-1030670...te-engine.html

stone150

iTrader: (2)

The 376 is definetely an option and I think It would be cheaper to build then a 454, but after I am not too sure how much cheaper, the blower is still going to run 5K+ and a turbo system seams cheaper, but you are just trading money, for the amount of time you spend on fab. I think for what I am looking for, a mid 10 to very low 11 second truck, a 454 or 427 with 11:1 CR, LSX-LS7 or ported LS3 heads, LS7 or LSXR intake with 230-250 cam, built 4l60e, and a 10 or 14 bolt rear end can get me there for 10-13K and have some reliability. My main goal is to b faster then My Z or faster then a mild bolt on Z.

CAMSTER

iTrader: (10)

Wiseco have the pistons you need #k462x185 and k462x200 which will make 443 Ci w/ 4" strock crank.

Blackpanther99

iTrader: (8)

Ill be worried about having a 4l60e handling all that power, specially on a truck that is heavier than a F-Body. I would think your best thing to do a 4l80e swap to handle all that power.