MY99TAWS6

iTrader: (3)

Seeing how would be building this for FI not NA figured can get some answers in this section rather than engine section.
I may have an issue with my current 408 iron block so looking to step up to LSX engine this time around likely around 427 to 454.

Questions..
I will be going of course forged pistons and rods and crank.
On my 408 went with wiseco pistons and hellfire rings. I had quite a bit of piston slap when cold which went away warm.
This time around would like to eliminate or minimize that. I have heard think diamond pistons are very quiet?
What pistons are quiet and should I get them coated or do they come coated?,what rings..total seal? hellfire again?
Also what does transfer over from my current 408 some of which was from my ls1 engine.
Does my f body oil pan,pick up,transfer. Can I use my slp double roller chain and poil pump.Are the water pumps the same.Lifters the same can I use my ls7 lifters, what about rockers can I use my yella terra non adjustables? Are do all the front end pulleys and all that bolt in front stuff bolt on no problem. What about intake. Assume current fast 90 dont' fit or will it if use my current afr 225 heads?
I was thinking though to go to six bolt heads. Are the trik flo 6 bolt good choice. Afr so far don't offer 6 bolt heads. If I use the 6 bolt heads do I need a different intake. A different fast? Was also thinking that wieand aluminum one but is that compatible with any 6 bolt heads. And do I need ls2 conversion kit for the LSX. Can I use LS9 cam on this LSX? Are they still available. I want a mellow no lope cam thats easy to tune ,easy on valve lift but that can still rev to 6500 range. Can a built 427 or 454 go to 7000 safely for just occasional 1/4 mile type runs?
So do I need LSX specific front cover,back cover, valley cover..
What else do I need to know to do this swap.

black98ws6ta

iTrader: (77)

If you plan on keeping your current turbo kit I would run a smaller motor and personally would use a aluminum block for weight savings(like from ERL).

laughatrice

iTrader: (12)

I just went through similar questions as you and settled back with a 408 an LSX block is nice but you pay a lot and after it's all said and done it's really heavy. If your going to upgrade I would do a ERL block or RHS but then your really deep in a short block my guess is 12K minimum to be done right.

As far as your LSX questions here's what I learned while researching one my information may not be 100% accurate so ask around.

-you'll need a LS2 style timing set
-I think it comes with a rear cover but no timing cover or valley cover so you'll need those
-you could use your stock LS oil pan but you should definately consider a aftermarket oil pan

All the other stuff you listed should be fine depending on your big picture setup.

98Z28CobraKiller

iTrader: (17)

Shorter stroke / Big bore is what I would do. My Wiseco's with the provided rings dont slap at all.

MY99TAWS6

iTrader: (3)

How much heavier is an lsx block over my current lq4 iron block?
I don't much care about weight. My car is like 4000 pounds currently me out with think it was 3/4 tank of fuel or maybe it was 1/4 tank of fuel. So 100 pounds lighter don't mean much to me.Street car not race car.

I think the LG turbos are up to the job with a 427 not sure about 454. So see no need to stay with smaller engine. Bigger cubes give quicker spool up, more power on and off boost.Can't really see much downside to a 427 except for maybe even less traction.

But if it weighs like 300 pounds more than current iron block then might have to wonder if its needed.I don't really want to get into megabuck aluminum motors wanted to finish up my 99 and maybe pick up a c6 then c6,c8..

laughatrice

iTrader: (12)

I'm not sure on the exact weight it's definitely not 300lbs. I think it's around 50lbs over a LQ9.

MY99TAWS6

iTrader: (3)

Ok looks like its 225 pounds total with ls1 being like 95 pounds and the normal iron block being like 175 pounds or so. So another 75 pounds not too bad. Aready have lighter kmember could maybe get lighter a arms and actually kicking around taking out my air conditioning as really never use it that could take off bet 75 pounds or so.
I already have lighter kmember. If really cared about front end weight could also move battery to trunk.

MY99TAWS6

iTrader: (3)

Also wouldn't boring it to 427 or 454 lighten it up a bit too?

black98ws6ta

iTrader: (77)

So you care about making power but you dont care about weight? You do know those two things fight against each other right? If you can buy parts that will do the job and are lighter you will end up with a happier, faster car. You might have a couple thousand dollars more in a aluminum motor set-up for 6 bolts as compared to the LSX

The LG turbos may be fine on a 427 but they will still make more power and be happier on a smaller motor.

Not trying to talk you out of your plans, just giving you my opinion.

MY99TAWS6

iTrader: (3)

The lg can do 70lb min each which should be lots for a 427 build might start getting a bit tight on a 454 depending on how much rpm you wanted/needed to turn. Factory cars often undersize turbos to give faster spool up and to get more boost in streetable ranges at the cost of giving up some up at the top end of the rpm range.Course push them too hard past their limits and they can die prematurely.

And realize traction will be even harder to come by on a 427 or 454 setup.
And repeat 100 pounds don't mean much on an already fat car. I am not into autocross,not into 1/4 mile trailer to track type racing with this car either. Just fun street car.

I do have a very light talon race car and will be picking up a vette maybe within next year or two which of course is a nice light car. These f bodies really are pretty heavy pigs but aren't that bad compared to the fifth gen f bodies.

All depends what you want.Can take out bet 75 pounds just by removing air conditioning if really feel the urge to lighten it up.
And honestly a tenth or so slower don't mean much either but really all you do is dial up the boost. Way more power available then I can ever hope to use. Hp can definitely make up for weight.Handling..well..car handles pretty decent even with current iron block. And you do need better brakes for heavier car. Already swapped them for c5 brakes with aftermarket pads and rotors. Helped quite a bit.

03supercobra

iTrader: (38)

X2 Turbos like the short stroke and big bore, you don't need a alot of cubic inches to make alot of power with a turbo.

TurboS10

iTrader: (12)

This reminds me of the saying "Your eyes are bigger than your stomach"

For a street car, a TT427 is simply for bragging rights. -period-
TT346's will spin the tires at 70mph.
TT408's will make 800 rwhp at around 12psi if you have the right turbos.
Call up VA Speed and get a LS3 based 370 short block or even an iron version since you don't mind the weight. Add one of their cams for way more than enough for a street car.
N/A 427's don't hook with street tires in first or second.
From what I remember from your previous posts, you have about 60mm turbos. They are border line on your 408 and will be too small on a 427.
Not to mention you don't have enough turbine to support a 427 either.

If your current setup is too slow, it's something in the setup. Not the "little" motor. My guess would be the turbos and cam.

MY99TAWS6

iTrader: (3)

I have the bigger LG turbos now but not installed. They are 70lbmin .The smaller aps standard are 50lb/min. I am pretty sure the 70lbers can do a 427 according to LG.
I have a 408 so obviously know about traction and spinning at like 70mph.
But current 408 might be fubared not sure yet. So if yank it can rebuild it or go up to the LSX. I have a few ideas for traction. Have set of et street radials that can run 24/7 possibly and have ramping options on my boost controller can ramp by rpm,time or gear. For street would think gear based is best or rpm ramping. For track time based boost ramping maybe best but car won't see much track.

MY99TAWS6

iTrader: (3)

This guy on here seems to be doing pretty good with his 427 setup. Same rearend ,same gears,same trans,pretty sure similar sized turbos to the LG upgraded ones I have.
I would be very pleased with this time and his 60ft. He is also at higher altitude than me by think about 2000ft. Car weighs about same which makes sense since we have almost same hardware.

I don't really expect to beat many cars on the street anyway. Like you said even a 346 with decent setup is not going to hook up very good on pure street tires.

This guy also is doing boost ramping by gear.
https://ls1tech.com/forums/single-di...98-146mph.html

Now I know you can get these times with smaller engines and more boost. But I do like the powerband you get from the bigger engines especially off boost and a lot of my driving is off boost.

MY99TAWS6

iTrader: (3)

This guy has 427 and exact same lg turbos I have. Again they seem to work just fine on a 427.
https://ls1tech.com/forums/forced-in...1040-rwhp.html

Course agreed not hooking this up on normal street tires.

TurboS10

iTrader: (12)

70lbs at what pressure??? 35psi?
Twin 60mm will push 1k on a 355.....
Same amount of air to push 1k on a 427.
Big difference in boost and where the compressors run on the map.
The lower boost on the 427 will increase the E/I pr and should get a different cam.
Can't tell what turbine comes on them. But it's small for a 427 turning some rpm.
A 370 with your heads and a different cam would be a better balanced package IMOP.

Big_Bird_WS6

iTrader: (7)

just my two cents on weither to go with alum, like ERL, or iron LSX. you said you dont want to get maga bucks in an alum. well at the end of the day. it is all about the same. the ERL 427 is 2600. you supply block.

the LSX is 2000 and i have heard you need to do about 1k worth of machine work to make it great.

so the price is around the same. save the weight. you have a street car. so taking off ramps and corners is part of the street car game. with the heavy *** iron in there, it will suck. i know oyu have iron now. but change nothing bup iron to alum. you will see a difference in the car. plus better weight transfer. so when you launch it, it transfers and gives you better traction.

___________________________

amd just so you know. a gt35 will be avalible shortly for the APS upgrades. and a gt35 with a 454 would be ****.

MY99TAWS6

iTrader: (3)

Handling is not high on my list. I have iron block now and not a big deal at all to me. And as also said still could lighten up the car mabye take out air,don't use it much anyway and could get lighter a arms move battery to back maybe,might be a few other things could do as well. I have strange da in front and can get ride height back to normal
height with them. It did drop a bit before installed the strange setup.

ERL might be an option I guess. Have to do more reading about them. Money is not that big an issue I basically get what I want/need for this car. Car is pretty much finished up with trans,rear end ,turbos,etc so just want reliable engine. I am as said not 100% sure whats up with the 408 yet. It has been working fine for 5000 miles then all of a sudden the other day the oil light came on. Didn't drive it far like that was only few blocks from home and it still made pressure as long as you kept some rpm into it.
So maybe is sender, maybe its pump relief valve,o ring, cam retainer plate,front plug ?
Or maybe its bearings and engine.
I will of course try to fix it first if its simple reason But if it has to come out then of course would depend on damage and buddy does work at local machine shop .Just that always said if the 408 came out then was putting in a 427. Was going to go 427 originally but figured didn't need it and it would be overkill. My original goals for the car were always 1000 engine hp or around 800rwhp. Thus my liscence plate.
And know can reach 800rwhp with the current 408 and LG turbos and have spray for small shots as well but so far its only in the car for show and intimidation.

This week I should likely know a bit more about my 408 as test oil pressure with mechanical tester and maybe get front of engine off to look things over. Or might be another week or so if order some replacement parts like oil pump,cam retainer plate..

98Z28CobraKiller

iTrader: (17)

When you take it apart, look at your skirts and the corresponding areas of the cylinder wall. I bet they are beat up. A piston designed to handle 1000 rwhp MUST have tapper in it. When that long stroke comes out of the bottom of the hole, the piston will rock. Believe it or not, it's the easy street driving that beats up the skirt. For this reason, we don't do 4" stroke anymore. Do whatever you want but at the end of the day, this is a real problem that wont go away if you build another long stroke motor for daily driving.

WARPNOVA

iTrader: (3)

Hey MY99TAWS6, I just got done dealing with allot of this and maybe I can help some. I, like Big_Bird_WS6 opted for the ERL option as I wanted to keep weight down even for my car which will be a 99% street machine like yours.

LS7 lifters I believe are a no go due to the 6th bolt for the heads being in the way of running the lifter trays. I know it is that way for me on my ERL block and from what I understand the LSX block as well. This means you have to run a link bar lifter. I chose Morel lifters.

I called and spoke with LG directly about the turbos and they felt that a 427 shouldn't be a problem for a street machine but expect it to run out of steam at 1000 to 1100 rwhp depending on cam and how hard you are trying to spin it.

I believe the LSX does have a special rear cover much like the RHS block which I looked into but you have run other special stuff like a longer timing chain due to the cam being placed higher in the block and there were a few other things about the RHS, but don't remember all of them off the top of my head, would have to look over my notes at home. The standard LS2 covers for the front and valley do however fit for either the LSX or RHS.

The RHS block is an awesome block no doubt but at $4000 plus and all the machining and extras you would need I opted not to consider it. Now if I was maybe looking for a nothing but pure race car then it would be great perhaps.

The LSX block adds loads of weight and that doesn't include all the weight of a turbo kit already up front. I like you don't mind if my car is fat but I don't want all the weight on the nose. Kind of like you don't mind a little fat on a women just not all on her hips you know. I feel keeping so much weight off the nose will make for a better riding car all around.

Timing chain choices for the LSX are the same as any LS2 you can run double or single and the block already has provisions for the LS2 chain dampener if you opt to run it.

Cam, you run an LS2 cam setup either 3 bolt or single depending on what cam you use, I don't know for sure what the LS9 cam is but I thought it was a 3 bolt style. Yes you will need to do the LS2 conversion to your car meaning the cam trigger and knock sensors will need to be adjusted for. Plenty of sponsors have the necessary wiring harness extensions to move the before mentioned sensors. You still use your LS1 knock sensors they are just in a different location. The cam sensor is an LS2 sensor and the wiring harness you will buy not only extends it to reach the front of the block, but I believe it changes the plug style too. Might be wrong on that maybe someone else can chime in on that. Won't know myself till I get mine.

I believe Yella Terra non adjustable will be fine as long as you can get your preload correct on the lifters with custom length pushrods. Otherwise you will need adjustable as I believe the aftermarket link bar lifters of whatever brand are more sensitive to correct preload then say the regular LS1 style.

Although the Trick Flow heads are six bolt nothing changes as far as the kind of intake you run and what not. I will be running my LS6 intake on mine and I opted to use the TFS 235 heads on my setup as well.

As for Pistons and what not I opted for Wiseco and Total Seal Rings. Maybe a little extreme but you can also run the GFX ring pack that comes with the Wiseco pistons and be fine. Wiseco I feel are the best piston for boost and if the piston rock is small like it should be you shouldn't have any piston slapping noise and if you do very little on start up. However I have read where people say 2816 alloy pistons will cause more noise than others which is why Wiseco coats the skirts to help provide better wear and noise control.

Everything else about the LSX block is about the same as any LS series block in that the oil pump, timing chain, pickup tube, and internals like pistons, rods, and crank are interchangeable. The specials are rear cover plate and lifters really.

Hope this helps you, I know it was though deciding on all this for me so good luck to you. I am sorry to hear about your engine going south on you, that sux the big one. Hope things work out better for you. If I think of anything else from my experience I will try and let you know.

Here is a link to my build if that helps any also. https://ls1tech.com/forums/forced-in...ton-rings.html