I asked this on LS1tech, and surprisingly, I didn't get alot of the responses I was looking for. Some good, tho.

Looking for options for building on a turbo'd 408...H/C, rod length, Stroke.. All info is well appreciated.

I am in the market for a 408 short block in about 6-8 months. I just need H/C ideas.. I am thinking 500-600 fwhp NA/ it will eventually see a turbo.

113, 114 LSA cam, but I like a lope.. I guess I can't have it on a Turbo engine combo. 225 AFR or TF heads, I know that much. Shooting for 10:1 or 9:1 compression. -What do yall think? How much boost will I be able to run on that setup?

This will be done BY about mid/early 08... the 408 at least.. give the turbo another 6 months to save for. Need fuel system ideas too.. 48lb injectors good? I'm no to up to date on the fuel systems for some reason.. was looking at the racetronix system.

Plans so far..The rest of my suspension is about done, just need a K and sways.. Trans and clutch is done... This will NOT be a strip only car.

K member
408 Short block
225 heads (will I need bigger? 240?)
90/90 intake
Will take to TSP for tuning... or use the EFI Live Auto tuner to get w/in range.
New Sways to finish the suspension
Strange 12b w/ 3.73's or a 9"

What am I missing? I am doing my homework.

 

You can have a lope on a turbo combo if you are willing to accept the compromises. There are some seriously radical set-ups,not what everyone is after.

 

What are we talking about? Gen I, II, or III?

Rich

 

I would assume he would be talking about a gen III with him talking about a 90/90 intake. (not trying to be a smartazz)

 

^ yeah, it'll be for my 2000 Z28..

 

Just talk to TSP. I'm sure they have built hundreds of engines like you are describing.

Sounds like its gonna be a badass ride when you are done. Good luck.

 

^ I'm currently 'interviewing' vendors with another member. They are an option, tho.

 

Are you planning on building the engine yourself or buying one assembled? Also didn't see anything talking about a budget? Also you said not track only.. are you will to put up with some quirts till you get them worked out or is this your daily drive?

 

Make sure you check with Victory Racing Engines when looking at vendors.

 

Not a DD. I'll have a truck in a couple months. I was going to buy a built short block and bolt a set of heads and a cam myself. I can built to a certain extent, but building the bottom end is something I DO NOT want to mess up, I'll leave it to the experienced.

Budget for the short block, I've just decided, is no more then $7,000. I found a Forged 408 iron block from a Vendor on another site for $6300.
Specs:
GM 6.0L Iron Block
Lunati 4.00" crank - 4340 forged steel
Lunati billet rods 6.125"
Wiseco flat top pistons 4.030" bore size

I think I may have decided on a Vendor for the turbo kit, but it will be pricey. Engine and turbo will run me $16,000 in total....So far..



.. Remind me not to total things up again...

 

ya if you keep track of all the money you spend it will only lead anger/depression. do your self a favor and forget, I did am an only done with most boltons

 

in case some are wondering.. I have the supporting mods. I'll need a rear, a K member and sways to finish the suspension.

THis is what I have so far.. (I have a LOT more, but this is all that matters for the engine conversion.)
Suspension
Hotchkis Lower Control Arms w/ Polyurethane Bushings
BMR Chromemoly Adjustable Torque Arm W/ Poly Bushing
BMR Chromemoly Strut Tower Bar
BMR Chromemoly Tubular Subframe connectors
BMR Chromemoly Adjustable Panhard Bar
BMR LCA Relocation Brackets
Eibach Pro Kit Drop Springs
Bilstien Re-valved shocks
Energy Suspension Trans Mount

T56 Rebuilds M6
New 1-2 Slider, New 3-4 Slider, New 5-6 Slider, New Reverse Slider,
New Mainshaft, New 1-6 Gears,
Carbon Fiber Synchros,
3-4 Billet Keys,
New Mikronite Finishing on 1-4 Gear,
Mikronite Finishing on 1-2 Slider and 3-4 Slider,
Steel 3-4 Fork, Bronze Fork Pads 1-4 forks, New Bearings

McLeod Single Disk Clutch, Kevlar/Organic Disc
McLeod Adjustable Master Cylinder
2002 Slave Cylinder

Weight Reduction
Fiberglass hood shaves 30lbs.
A/C Delete -40lbs
A.I.R. Delete -7lbs.
EGR delete -5lbs
Spare tire and Jack -25lbs
Removed sound dedening material from sail panels and center hump.
Removed wiring harness for rear speakers. -Both about 5lbs.

 

I'm not sure how long a McLeod SD will hold under the power of a turbo 408. Just a thought -- plan on replacing that with a Street Twin when it wears out.

How much did you spend to have all of that done to your trans? I'd like to do something similar...

And the rear speakers still work after this?

 

You need to keep in mind what turbo you're going to use and what your goals are. For instance, the T76 won't work well with 408 cid. A 408 will need a much larger turbo to work right and the larger turbo doesn't fit well in the bay.

What are you goals? mph? rwhp? race gas? pump gas? idle quality?

BTW, no one has proven that lumpy cams with alot of overlap are actually bad for a turbo car. In actuality, the opposite has shown to be true.

Something that I've really been wanting to see is a setup optimized for the small T76GTS turbo. It would be something like 327-346 cid with AFR225 or L92 heads, cam in the 236/242-112 range, tubular headers, 3.5" downpipe, 4" exhaust, T76GTS .96 AR, water/air intercooler. I bet it would get close to 150 mph in the quarter on pump gas at the right weight and 160 on race gas.

Mike

 

Also, any kind of self-respecting turbo F-body will not need that much gear. I'm pulling 6400 rpm through the traps with a 2.73 gear in Drive.

Mike