Petey-Pop-383

I want to build a 408 nitrous motor based off a 6.0L Iron block. I will use the appropriate bottom end parts (forged crank-rods-pistons/main studs).
It will also be a carb'd motor with single plane intake, and I would like to use LS3/L92 style heads.
I want to run 8.60's to 8.80's @3200lbs, drag radials, glide with brake 1.80 gear set.

What other parts/requirements are required to reach my goal?
-I was looking at the Trick Flow GenX255 heads, would these be a good choice.
-Can I make the power I want with a hyd. roller cam, or should I be going to a solid roller?
-What compression is needed?
-Stock Rockers with Trunion upgrade or Roller rockers or Jesel/TD Shaft rockers?

Im open to all opinions and other peoples past builds and engine combos.
Thanks,

Dynospeed

iTrader: (3)

Well the more power you make na means you don't have to hit it with 400 to meet your goal. I ran a 8.6x last year @ 3180 with the same trans and tire. You didn't post up a budget so mise well go with a lsx block and get the 6 bolt heads and extra cubes. I love the Trickflow heads for a semi budget build. Also the 245's / 255's will really like the larger bore. Also go with the Super Vic over the Jr unless you have Mast intake $ then go with the Mast. Give us a little more info on what parts you are stuck on reusing and how much you have in your budget for the other parts.

87silverbullet

iTrader: (11)

Are you going to try this on pump gas? If so I would stay hydraulic if not then I would go solid.

Reason being is that with more compression you will need a bigger cam and that will end up turning more rpm in which a solid will keep the valvetrain more stable. If you stay pump gas compression, the valvetrain stuff has been covered from front to back and then some. There will always be a spring for whatever hydraulic setup you go with.

Just an FYI, there is no Super Vic for L92/LS3 heads. From what I have been hearing, it won't be until April before Edelbrock releases an LS3 super vic. Still, take that with a grain of salt.

Petey-Pop-383

I'd like to use the 6.0L iron block if I could. The way I look at it, if I go LSX then I would want to take advantage of the possibilities and go 440-460cuin, but then I need bigger heads, bigger exhaust, bigger intake, and the ball starts rolling...

So for this motor I would like to use a 408cuin (or around there) and the 6.0L iron block.
This definitely isn't a budget build and I'm not afraid to spend money on good parts, solid roller cam/extra CNC porting/lighter valves/etc if the gain is justified ie. performance or longevity.

I was thinking K1 or Callies crank and rods, a quality piston with pin upgrade for heavy nitrous use.
I have looked at the GenX255's and would be open to getting some work done to them so they are more designed towards nitrous use.

I was thinking either the L92/LS3 Vic Jr intake or the newer Super vic.

I would like to keep it hyd. roller if I can, and if the cam dictates that I need to upgrade from the stock rockers with trunion upgrades I will go to jesel's or T&D shaft rockers. Or possibly roller rockers, yella terra etc.

My thought process on this engine is that I have seen junkyard 6.0Ls with shaved LS3 heads, flycut pistons and decent sized hyd. cams run 5.90s @ 3000lb on a 150 shot.
So if someone were to build a 408 stroker with good internals and machine work, a set of 255 heads, aggressive cam, correct compression for the engine it should be able to run in the mid to higher 8's on a healthy dose of nitrous. 300hp-400hp. I'm I out in left field here?

Let me know if you need any more details to help me out.
Thanks Dynospeed and nice times with your car!

Petey-Pop-383

87SilverBullet I would use race gas at the track, but would still like to street drive it on premium pump gas. When I say street drive just cruz around, no nitrous or all out passes on the street. Maybe back the timing down on the motor.

I was thinking around 11:1 to 12:1 for compression.

lemons12

iTrader: (71)

Im 11:1.. Ls6 heads ported milled.. Fast 102 combo.. 1 7/8.... Aggressive cam..
400 trans..
8.8 rear...

Stand alone with full race gas and a mix in the tank..

Im shooting for 8.8s on a 300 hit @ 34xx race weight.. Im 175.

Im worried about the heads.. I will swap to a tfs 235 later.

I make around 515/490 on motor right now.. That was with a 4900 unlocked converter kn a mustang dyno. A 3500 is going in this time.

Carter01 is helping me achieve this.. Hope to see 8s at fest... Which would make me happy since usually everyone runs a little slower that usual at fest.

BSmiff

http://www.yellowbullet.com/forum/sh...023&highlight=

^^^Talk to this guy he went 10.0s on motor with a nitrous combo. I think he ended up going 8.60s with a single kit.

87silverbullet

iTrader: (11)

That car weighs 2890 with nobody in it and has carbon fiber doors. The 8 second passes on nitrous are with a 408 he built. Not the 383 he has in that thread. He is on tech but I forgot his screen name on here.

That 408 has some high end parts on it too. Mast intake and the compression is somewhere in the 13 range.

WhiteLTone

iTrader: (18)

It's all in the combo. Converter, cam, and nitrous kit are the important things. My 347 went 8.80's all day on a 300. 2950#
Make sure the cam aad converter are specd for the amount you'd like to spray

WhiteLTone

iTrader: (18)

Talk to steve at Legend. He's been building a bunch of nitrous lsx motors recently and has some great cam profiles.

(SS)

iTrader: (1)

Take that 6.0 and bore it .30 and make it a 370ci.Go forced induction and be very streetable and be a track monster.mightymouse comes to mind.

Petey-Pop-383

BSmiff - thanks for the Link

87SilverBullet - I'm going to try and use 11-12:1 compression and Edelbrock intake if I can.

WhiteLTone - Once the cam is selected, I'll get a converter to Match (PTC/ATI/Pro-Torque) and I understand it could need a re-stall or two to get it bang on.
I'm leaning towards a direct port kit from one of the well know installers/tuners.
Can you give me some more specs about your 347 motor, killer times out of 347cubes! I will reach out to Steve@Legend once I get a better Idea of what I want. What kind of services does he provide?

(SS) - I though about a boosted motor, but I just like nitrous cars better for what I am looking to do.

Thanks for the help and input so far guys.

87silverbullet

iTrader: (11)

Thats all still pump gas compression. You can run pump all the time and even race on it with that compression and then just get a standalone with c16 in it for the spray.

Petey-Pop-383

I have a cell in the trunk and a large fuel pump (Prostar 500) for both carb and nitrous fuel, so its not hard at all to empty the pump gas out of the cell quickly and cleanly into a fuel jug.

87silverbullet

iTrader: (11)

Well that makes it easier then.

I will tell you this though, it gets old quick to pay the price of race gas and then to try and find it or get some at the last minute.

StrokerTA

I am finishing a 408 build in a full weight 98 Trans Am, I fully expect it to go 8.60's or quicker..
It has a set of in house ported LSA heads, custom ground hydraulic roller, under 12:1 compression, and 2 stages of Induction Solutions nitrous..

And, it's a street car with a 12 bolt and a TH400...

I also am the one who built WhiteLTone's motor.

Petey-Pop-383

I'll reach out and contact you Stroker TA, did some searching on the net and your name/company came up a couple of times.

What options are there for nitrous pistons for the LS3/L92 style heads that are good for heavy nitrous use 300+?

Thnx,

87silverbullet

iTrader: (11)

Are you wanting to use LS3 heads for a certain reason? There are some good small bore LS7 heads out there that really shine on 400+ cubes. Something you might want to look into.

Petey-Pop-383

I have an LS3 Manifold I would like to use.

But I would be tempted to switch if the gains of the LS7 stuff justified the switch.
Are the Trick Flow GenX255 heads not based off of the LS7 stuff?

87silverbullet

iTrader: (11)

No its based off the LS3 port but the valve angle is like 13.5* compared the the stock 15*. The LS7 has a different port and the valve angle is 12*. People have made switches from ls3 stuff to LS7 stuff and made considerable gains on 400+ cubes engines