N/A86

iTrader: (10)

hi, i need some help choosing valves and springs, and any other advice i can get for my 408/l92 engine.. its a N/A fuel injected build for a third gen that will see plenty of street time however most will be pounding on it, it will also have to make a 400mile road trip from detroit to buffalo a couple times a summer.

what i have

livernoise 408 iron short block
-should be 11.5/11.7 for comp
-ptv shouldnt be an issue, i had wiesco make a set of domed pistons with
valve releifs for the l92's
new L92 assembled heads
GM mls head gaskets, arp bolts
ls3 intake with stock injectors
comp cams upgraded lq4&Ls3 rocker arms
LS7 lifters
cloyes single roller ,billet i belive
2in long tubes

what i still need and could use advice with
camshaft-plan is the esp lobes and have Pat G spec it
valve springs- mabey brian tooley???
valves- mabey ls3 intakes and ???exh
oil pump- plan is ported ls6 from texas speed


any help and advice on what i have and need would be very helpfull, ive never done this before so im a new guy . im not sure if i should have the heads touched up or ported.. i noticed there are some sharp edges around some of the cc's and im also very curious to what i can make power wise(really hoping for 500 wheel)

also the car is a M6 car

thanks, Adam

lil john

Nothing on, watching ole Law and Order episodes.
Looks good don't try and think of cam specific's just ideas of what you like is sufficient, Pat G can make it to your liking 500rwhp wanted email him and a 500rwhp cam is no longer a question. After which Pat or Brian can set you up with springs, retainers... etc.
Hollow stem intake and exhaust factory valves work good. Brian on these also if my memory serves correct.
Melling high volume oil pump. Hope this helps. Looks good.



Ported heads really would wake things up throw in about a grand for professional porting.

Tuskyz28

Great build you got planned..I agree with John about having the heads ported tho. Just don't let anybody port them if you know what I mean. Everybody claim they can port these rectangular heads can't. A cam along the line of a 238/254 ...... on a 114+4 should put you there pass your goal with great drivability for long trips..

N/A86

iTrader: (10)

thank you, should i go with a stainless intake valve or a new LS3? and also as much as id like to have the heads ported in that range ( talking cnc i assume?) that wont be in the budget. i do however have a local engine guy that does our ashfault modifyed motors offering to hand port them for an affordable price, but he said for the gains id get i wouldnt feel the diffrence on the street and i should spend my money else where.... thinking ill pass and have them cnc'ed down the road

lil john

Hollow stem.

Dickspeed

iTrader: (3)

Sounds like a great project
Don't go too big on cam lift, limit to about 585 - 600 at the valve
GM Racing use PSI 1511 beehive springs with stock retainers an keepers for much more radical builds than yours....CV Products sell them
Use stock LS3 intake valves and the 6.0 truck exhausts which are Inconel material and will be much more durable.
A decent valve job on stock heads can pick up 7-8 HP especially on intake side and might do just as well if not better than someone hacking at the ports!
Have fun

Last C5

Sounds good, I would recommend some Smith Bros restricted flow push rods.

Tuskyz28

Last 3 guys posted all gave you great advice. I'm just kinda partial to btr 660 springs. They are great to have.

N/A86

iTrader: (10)

thanks guys, I was also leaning towards the btr 660's they seem affordable too. and so I may be better off using the factory ls3 valves, how about a ferrea hollow stem? my engine builder is really leaning on me to do a manley of ferrea 6000 idk if hes under qualified in the lsx world or just afraid of the hollow, but ive really never herd bad about the stock ls3

Havoc40

I don't necessarily agree with restricting the oil flow @ the pushrod. Engineers spend a lot of time achieving the proper oil flow from the pushrod seat in the lifter. This flow has a direct affect to the dynamic performance of the lifters themselves @ high RPM (i.e. SpinTron). When you restrict the flow from the pushrod, you're increasing pressure inside the lifter. Once this happens things can get out of control and cause valves to bounce.

I'm not saying that there is zero advantage to using these in some cases...but I'd want to see the testing to prove it works with a given combination before placing them inside my engine.

TurboBuick6

iTrader: (2)

I would run more lift. At least .620 closer to .650. Duration in the high 230's to mid 240's. Ditch the LS7 lifters for some morel drop in's and if you want to hit 500RWP you will need injectors to feed the air. Don't run restricted push rods either. That is how your valve train is getting oil.

Gray86hatch

iTrader: (83)

Restrict the push rods to keep from filling the valve covers. I have never seen issues with doing this.

Tim

N/A86

iTrader: (10)

im most likely just gonna go with a btr pushrod if im going for there springs, and as far as the lifters I already have the ls7's .. and im not sure what the lift will be , ill just go with what pat g says.. as far as the valves tho my engine guy wants to use a solid valve, I know the LS3 holds up but will it be ok with a large lift/ heavy spring yada yada at 7k for long periods of time? and not need a rebuild for a while? will the solid in valves actually hurt me? and still not sure on ferrea's competition hollow valve

Jason 98 TA

iTrader: (4)

We have PRC ls3 hollow stem valves in stock for ya. give us a yell if we can help in any way!!

TurboBuick6

iTrader: (2)

If you do decide solid valves you really need to ditch the LS7 lifters in order to run a set of PAC-1208X's.

N/A86

iTrader: (10)

I will be doing a solid ss valve on the ex side for sure, Why do you suggest against the ls7 lifters? I really am getting out of control on this build, I'm already closing in on $10,000 and still not close to the end. I've herd good things about the ls7's is there something I need to know? I'm leaning towards the hollow intake valves they seem to not have many issues I guess. I like the idea of the stronger solid valve but there 40 grams heavier... My engine guy says it will make no noticeable difference and that he has used both on 9k revving engines, However he is new to the ls world. He builds ashfault tour mod engines all of witch are gen 1 style and mostly 18 degree heads

N/A86

iTrader: (10)

And will there be an issue with the btr 660's? Everybody seems to love them and at 300$ they seem like a good choice to me I don't want to build a drag car here, it will barely ever see the track, I will have an aggressive cam but it's also a M6 car that will be street driven so I don't want a ridiculous cam I figured with the 408 ls3 combo through the manual I can reach my 500whp goal with out going too crazy

TurboBuick6

iTrader: (2)

GM lifters don't have great quality control. Some are good some are bad. I will never run a GM again. On the exhaust side I would go sodium filled if your worried about heat.

The patriots were the best thing since sliced bread until they went under. After that all you heard was how many failed and how horrible the were. Do some homework. You get what you pay for.

N/A86

iTrader: (10)

Hmm so a sodium filled may be more reliable than a solid stainless? I still have the stock new l92 valves

TurboBuick6

iTrader: (2)

My car is a summer DD. 60 miles a day and I run it hard to 6,800 every time it's on the road. That's at .650 lift too.