Ok here's the idea and I want to see what you guys think.

4-bolt LT1 block...either made that way or 2-bolt with splayed mains.

Scat Billet Crank

5.7" forged steel con rods

custom pistons for a 1.8" comp height with slight dish to hit 9.42 comp.

afr 227 LT4 heads

58mm T/B ported ( )

behind it will be a th400 with a brake and a 4500-5K stall

all going to either a 12 bolt or a 9 in. with a 4.11 gear

28x11.5x15 ET Drags

Front runners on Prostars

caged

all the other goodies

first is it good for 1K+ hp??

second what e.t. do you think I'll run??

oh yeah there will be a T-88 in an STS turbo kit mounted out back with Hooker headers running to a Mufflex intermediate pipe feeding my huge turbo.....max 20 Psi of boost on 114 octane.

Simulations put this motor anywhere from 1200-1700 HP. with an off the shelp grind from Comp.

Chris

 

How does that turbo respond back there?

 

Everything sounds good except the "turbo out back".Your program does not take into account the turbo is that far away from it's drive source and it might be hard to spool up that far away from the engine.

 

Thoughts:

If you mean 408 cubes, doesn't that require a 4.00 stroke and about a 4.03 bore? With a stock 9.025 deck that gives a 5.225 rod at zero deck. You probably meant a 1.3 compression height, right?

1700 hp from an LT1 block? Good luck. Maybe you hp estimates are a little high, like 40%?

Off the shelf grind for an absolute max effort engine? Strange economy, IMO.

If you only need about 975-1025 ponies, try a turbo'd Ecotech 4 cyl from GMPP. It's a bolt together easy 925fwhp and will live. That would really shake up the troops when you lifted the hood! About 100 kilos lighter on the front end also.

 

Sounds like Internet dreams to me. I am not sure what you are asking, but it sounds like you are building a drag car. Unless there is some damn good reason, you shouldn't even consider an LT1 for that purpose. If you don't want a big block, use a gen I or a C5R block if you pockets are really deep. If your budget is in the $60K range, it's approaching realistic.

Rich

 

Well First it's a customer's car...side job

Second he wants to go fast and still use an LT1 Block. and as for the turbo out back, that's only an option. We still may go custom headers into twins, or custom into a big single. We're still undecided until we hear back from STS regaurding a Kit to support everything.

And what the sims say are totally higher than my expectations....I'm guessing more in the 950-1150hp range. I plan on getting every bit possible out of this motor and I DON'T plan on using an off the shelf cam.... That was just from what the Sims said...I plugged my numbers in and HP#'s went up on ave. 100hp. This motor is still in the planning stages right now. The car will be a dedicated 1/4 miler with the once in a blue trip out on the road. There will be headlights, tail lights and even a horn. Race weight will be right around 3400lbs.

 

Well, here's my thoughts.

It will need a good set of heads and a top notch valve train. Pay a lot of attention to the exhaust side of the heads and the headers/exhaust system. It will be making a huge amount of combustion gases that need to be exhausted. Choose a larger exhaust valve at the expense of the intake as compared to an NA motor. Obviously, the cam choice will be critical.

I would avoid any more overbore than is absolutely needed. I don't know of a common bore and stroke combo for an OEM SBC "408". Is it a 4" stroke and 30 over? I don't think that extra displacement from a 4" stroke rather than the commoner 3.75" ("383") or 3.875" ("396") is worth it. The problems are both clearance for the big end of the rods and the extreme rod ratio needed. My choice is a 383, though a 396 can be made to work. In any case, go 10 over and not 30. This thing will make huge cylinder pressure and will have poor ring seal and be at great risk of a split cylinder at 30 over.

Get a set of billet rods. Olivers have great stroker clearance.

Rich

 

Actaully I was looking for a good set of rods and had yet to find one that I liked. As for dropping displacement that is most definately an option as We'll be getting the block this weekend and then decideing on machine work. I may still drop it down to the 383 as the 408 was just thought of to be different. And from looking at all logical standpoints the 383 will make more sense in the Comp. Height and Rod length areas. Especially planning on putting big boost through it. I'm really not comfortable with a very small...ie. 1.01-1.50 comp. height. So I'll have to talk with the customer and see what he thinks, but he doesn't really car as he really just wants a time slip. And that's not the hard part considering the car has run 12.17 on stock suspension, BFG drag radials, 2800 converter and shorty headers....oh yeah the Bailey electronice LTCC and 150 shot with 2 degrees of timing pulled out. So it runs pretty good so far.

 

Why stick w/ a 408 combo? Just seems like more trouble than it's worth. You won't gain that much over a 396 or even a 383 and it'll cost a lot more and probably wouldn't be nearly as durable. I can understand the whole point of being different, but is that really worth the extra $$$? I'm running a 383 w/ a 5.7" rod and AFR heads and a completely custom fabbed twin turbo setup and it's a league apart from being "different." The money saved by going w/ a 383 over a 408 or anything custom will be quickly devoured by the turbo setup ($3000-$3500 all DIY), fuel system ($2000-$2200 all Weldon and braided line) and drivetrain upgrades (TH400 & 12-bolt) necessary for the power it'll make (invest in brown underwear).

Also, just drop the whole rear-mounted T88 thing...that'd never work and be efficient...EVER. Scoop up some 1-3/4" mild steel and make the headers for a traditional single. I used 1-3/4" bends and donuts for the manifolds on mine, 4 1-3/4" u-bends for the wastegate piping, some misc. 3" tubing that was laying around the shop for the downpipes and a LOT of 3" and 2-1/2" aluminized pipe for the intercooler and cold side stuff.

 

Here is a guy that has a 1,000 horse procharged LS1 and has the plumbing going to the rear.

http://www.gmhightechperformance.com...s/0407htp_bad/

 

Little bit of difference in using a blower/normal turbo setup with an intercooler mounted farther back and trying to run a large frame turbo where the muffler usually sits. The supercharger will pressurize that pipe in no time flat, the large frame turbo will take more time to spool because the exhaust gas will lose alot of heat energy before it hits the turbo. FWIW, my friend runs a 240Z with a similar set (the intercooler is where the passenger seat once resided), the 106mm turbo is mounted up front, close to the engine and doesn't have any problems spooling. The car runs in the 7's and is occasionally driven on the street.

 

That plumbing is the IC piping. I believe it's going into the cab to a water/air intercooler and then back out to the motor compartment. Completely different situation

 

Couple thoughts that others have mentioned, but I will just repeat.

Go as little overbore as possible, .010 would be nice. Custom pistons to go along with this, made differently than the off the shelf kind.

Rods, oliver billet, or carillio (sp) are the only things i would run.

Crank... I disgress here from the crowd. I personally think a stout (callies/crower etc) 4340 crank would work well. You wont have the sudden "hit" of nitrous to worrry about flexing it, and dont have a supercharger pulling on the snout.

 

Big BIG difference between Ronnie Duke's car and an STS car. That's like saying a DOHC motor is the same as a pushrod motor because they both have pistons.

I think you'll be fine w/ a .030 overbore, but I'd definitely look into filling the block. Fill it up to the freeze plugs and you should still be able to drive it on the street every once in a while (wouldn't DD it by any means).

 

ok here's an update as of this weekend and talking with the customer...

Ci. reduced down to 383 for part availabilty and Comp. Height reasons.

Turbo is still going to be big but we have yet to decide on one or two.

Either way it will be mounted up front with an intercooler, best part is trying to find somewhere to put it As for the rearend we've also settled on a 9" for strength reaasons over the 12 bolt and the fact that gear changes will be a lot easier with the 9".

I'll most likely be making the headers and possibly the intake if we get crazy. The only reason I want to make the headers is for space constraints as well as I'd like to use little bit bigger pipes than the PTK Kit. I'll definately keep you guys posted as to how things are going..

Oh yeah the block we got had a spun rod bearing that ate the crank away a good .020 at least. (minor stroker right there ). We''l be getting this thing going here shortly and I'll even include some pictures for you guys along the way.

Chris