It will probably cost more to go turbo but you will also have WAY better behaved car because of the smaller cam and gears used in turbo cars and also better MPG.

As for going 10s you thinking high mid low 10s big difference? 500rwhp is more than enough to get you in to the 10s with the right mods for traction(tires, suspension).

 

400 rwhp on a mustang dyno (about 440-450 dynojet) will get you into the 10's, with a somewhat lightened car.

AND FWIW, I never said anything about building a motor AND buying a turbo kit.
You can run a stock truck motor at 10-12 psi on a safe tune for a VERY long time. and swap em out for cheap if they do fail. if I had to do it again; I'd do a stock 5.3 short (or 6.0l), 6.0l heads. upgraded springs and maybe a cam. 60# injectors, and a safe tune. and then run the **** out of it. when, or IF, it pops, get another 700$ shortblock.

You could probably do this for around 1500(6.0l, springs, cam) +the turbo kit. a truck manifold single thats what? 3000, less? so your at 4500-5000 and have 7k for a rear, suspention, trans, converter, fuel system, and a tune. very doable.

I put 45k miles on my car with no issues related to boost. made 520rwhp on a mustang dyno at 9psi, and turned it up to 11.5-12 psi on a cold day. running 132 mph at 3900lbs. It wasn't dyno'ed at that boost level, but I;d guess it to be close to 600 or more.

The only thing that went wrong was the factory cam had a porous lobe that eventually broke a piece off and ruined a lifter. I already had a forged shortblock ready to go, so it got swapped when we took it apart. otherwise, a new cam and lifters and I'd still be running the stock motor.

I'd suggest you figure out exactly where you want to be. a 600hp motor costs a LOT. a car to run 10's, maybe not so much. If its LOW 10's your after, on motor, your budget might be a tad low.

 

good stuff dude hoping to the same with my friends car

 

And he's not exagerating either I'm very familiar with the car. The factory shortblock is out in my shed.

 

Maybe I missed it, but do you want 600 at the crank? or at the tires?

Our basic 408 package makes 500 at the tires, making more is not difficult, but drivability suffers as you increase the hp per cubic inch much past that point. As was said earlier, an LS2 block or larger is highly suggested for this not only for the cubic inches, but for the airflow afforded by the larger bore unshrouding the valves

I'm doing a 427 big bore stroker for a buddy right now with the Darton sleeves and LS3 heads - looking for mid 550 on that one.

 

Build a stroker in this range - 4" stroke and around 4" bore - is the best deal in LS motors. You can put stock LS3 heads and make near 500 to the tires with the right cam. Get an iron block, and it will take pretty much everything you can throw at it (if tuned properly of course). Plus a used iron block is cheap, and you can start at 4.005 and get a rebuild or two out of it.

-Geoff

 

Yep - the LS3 heads are a great value, ~$700 + a valve job they'll support 500+

I do prefer the aluminum block for the weight savings though.

 

I liked Aluminum until my buddy split two of them with his turbo kit (making sick power but still). They ended up going with an iron 5.3 and bored it out to 3.90. Haven't had an issue since. If I was going out of the 500's I would go iron.

-Geoff

 

Yeah, for heavy boost or nitrous, the iron block's rigid cylinder walls are better - I have a couple 6.0L iron blocks set aside for these types of builds.

 

600 hp at the motor flexplate/flywheel is 500-520whp. This is doable on stock 346 cubes. This can be run on the street on pump gas. This will be a wild little motor but it is doable. I'm not sure the issue here? Should not be anywhere NEAR 20K or 10K. you can buy a crate LS7 with bolt ons that will do near 500whp for much!

It will take a great set of heads, good rotating bottom end because it needs to spin 7K+. I'd say a good ported EFI single plane, or MAYBE a fast 102 for the rpm. I've just know the single planes have done it.

Could do it with a hyd roller cam, just suggest Morel lifters to handle the spring pressures needed to turn 7K plus with an aggressive cam.

If you can start with a 4" bore block, this will open up the availability of larger valve heads for more airflow...making it abit easier to make power.

Pat G did 500whp on stock cubes many years ago. Things have gotten better these days.

If you can do a stroker, that will make it 10x easier and be near same cost. Figure you need new crank/rods/pistons anyway, and most cranks cost the same even tho stroke length changes. So might as well go longer stroke to get some cubes. Cubes will move things down inthe power band more and make more torque...all important on a street car. More cubes,sub 7K rpm power, 500-550 is easily doable at the tires.


For those that mention turbos....my friend has done several stock truck motor bottom ends into the 600+ whp range. Nothing more than rod bolts and camshaft, some with ported heads/ls6 or ls2 intake. Iron 4.8L with heads/cam 702whp at 7500 rpm on 16psi...stock bottom + rod bolts. Iron 5.3L, cam only, arp rod bolts, 676whp at 6500 rpm 12psi pump gas. Aluminum 6.0 LS2 with ported 317 heads/cam, 811whp on 11psi E85 on a stingy mustang dyno. Stock bottom just rod bolts

Dont overlook a boosted bottom end...dont need much to handle big power. Cheaper and faster if you can fab a turbo kit yourself than goin all motor

 

The issue is that he wants 625hp+ The cost to rebuild the stock rotating assembly is only a few hundred cheaper than buying a 402/408 shortblock. The stroker will make the power he wants without issue, and will do it with off the shelf parts. The 346 will need everything setup perfectly to make that kind of power with lots of attention to detail, it will be run near it's limit, and it won't be cheap. The top end expense will eclipse the savings in the rebuilding the stock shortblock.

And I simply cannot believe you're recommending a single plane for a street car You should know better!

 

I love me single planes.. dont worry about low end, just gear/converter it til it works. Properly prepped single plane will eclipse a Fast above 6500-7000 rpm Thats where power is made on little motors

My turbo car uses one no issues I may do one on my LS1 car if I build it up a good bit. Seems to be cheaper than fast intakes....

 

Orr89rocz, the issue I took was that he wanted 600+ hp (unsure of flywheel or rwhp). Can be a big difference netween the 2, I know. AND he wanted 500+ tq. which I feel is the somewhat hard part, especially if rear wheel.

Post #5 "Power goals are somewhere around 625HP, 500+ Torque.... AND keeping it on pump gas."

I haven't followed stroker builds for a while, but Im willing to bet 625/500+ on pump isn't cheap. at least not 12k cheap for the whole build. especially when you have to factor a converter, rear, trans, and tuning to make it live.

Thats why I posted what I did. LOTS more options with FI to get what the OP wants, and keep it street friendly, on pump gas.

here is an example I just read about a 408. Its 10K just for the motor, and makes 550/508 flywheel. So its close. maybe its not quite the stretch I thought.

http://www.gmhightechperformance.com...ice_total.html

I guess the question is, how much more $ is the extra 50+hp gonna cost? and if the OP wanted rear wheel numbers, thats probably another 75+hp. I bet it starts to get pricey from here.

 

So you recommend trading 50-60ft/lbs torque from idle to 6000rpm for a 10hp gain above 6500rpm only? On a street car? I guess you suggest he runs a 5.13 gear with a 6000rpm stall torque converter, right?

You have a SBC in your car, not an LS engine. They respond differently. You need to do some research on the LS engines and single planes because you're giving bad advice!

And to rod442: I have that GMHTP issue and remember reading along as they built that 408. That 408 was a joke!

 

I dont know about that. Thats why I said properly setup and if using a small cube motor that wanted to make high peak hp, no issue there with running more gear and stall. It wouldnt be that excessive as you mention but it could work. Just going by what my cam guy tells me. He's done some single plane 521+ whp 346 cube setups. It has beat the Fast 90 intakes. Now I'm not sure how the 102 works on a all out setup. But a single plane without an elbow type TB does make power when properly setup up and matching cam. It takes a different cam than what works with FAST.

Stroker build should be considered here for the torque and hp.