looking for 700 rwhp in my 97 C5......... would a forged LS1 hold up on a safe tune or do i have to swap in an LQ9 ? really dont want the x-tra weight
up front from the iron block or not really wanting an LS2.
thanks,

 

A ls1 block with good pistons and rods will handle 700rwhp. I would use aftermaket head castings to keep the headgaskets sealed. What power adder are you going to use?

 

The extra weight is really not as big of a deal as most make it out to be, but if you're dead set against it the LS1 can be built to easily handle 700hp worth of FI.

 

was thinking about the a & a corvette T-trim supercharger. was gonna go 383 forged lower and a mild blower cam.....what heads work the best for FI ?
AFR , Trick Flow , PRC's ?

 

I have a Forged LS1 with TFS heads, comp cam and a P1SC on a "SAFE" Tune @ 14.4 PSI and I have:

701 RWHP
582 RWTQ

With plenty of room left

Thanks,Matt

 

Yeah 700hp on an ls1 block is way too common these days.. or at least it is on this forum

Call any of the big builders/sponsors and they'll help you out.. they're the ones qualified to make that call.. but I don't see why an LS1 block couldn't handle that or a little more.

 

now that sounds promising.....

 

Do the 8 rib belt upgrade while ordering the kit. This will help eliminate belt slip. All three of the heads you named will work great. I would personally get trickflows. I would use twin fuel pumps and meth injection at 700rwhp on pump gas. Better safe than sorry.

 

Got over 15k on my 347 forged setup, I have went over the edge now at 20lbs, I expect it to go south faster now, but after 4 years of 14lbs I was ready for more boost. So if you are looking for around 700 rwhp you will be fine with a LS1 and even 243 cast heads setup for a blower like I use

 

Give matt a call he will help you all he can, Very nice guy.

Steve will also has a nice set up and will help also.

 

Im using 243 stock heads and over 700

 

The LS1 will hold up not that 85# extra with an iron block is that big a deal.You're already adding weight with the supercharger.
Good luck.

 

Ya.... I figured 80 lbs. On the block and 80 lbs on the blower....that's a lot to add on the nose when people spend thousands on weight loss..... And would still have to have a forged lower..... Unless the stock LQ9 will hold 700 rwhp . I do have a 40k LQ9 sitting in my garage :-)

 

go with LS1. LQ9 being iron heavier and harder to cool.

 

I did a ton of research before doing my motor build. Asked long time motor builders lots of questions.

The LS1 block wasn't designed for more than 600hp, they just flex too much. That means less than 500 rwhp. Sure people have pushed these blocks much higher, but will they tell you when it breaks? Do they drive them hard, or just get the dyno numbers then sit in the garage? You have to ask why the LSX isn't made out of alum? After going through all the time and expense of a motor build, you want it to last for years don't you?

LS1 < 600 hp
LS2 < 750 hp
LQ9 < 900 hp
LSX < 2000 hp

If the weight is really an issue the aftermarket alum or C5R blocks are the safe choice. And also don't skimp on the lower end. Billet main caps to replace the factory cast units. Dowel pins are used on the mains to prevent main cap walk.

I think the perfect 800 hp FI engine would be a LS9 short block from GM is they ever put something like this out. It's lightweight alum and built to handle more than the LS2, but doesn't cost an arm and leg like the other alum blocks.


http://corvettemuseum.com/specs/2006/LS7.shtml

"doweled-in-place CNC-machined forged steel main caps"

http://www.corvettemuseum.com/specs/2009zr1/index.shtml


http://www.hotrod.com/howto/113_0504.../pictures.html

"Centrifugally supercharged street engines of 700 to 1,200 hp should consider the cast-iron 6.0L truck block, with 800-plus horsepower engines using dowel-pinned steel main caps in iron blocks."

"Also, on supercharged, turbocharged, or nitrous engines above 900 hp, a main-cap girdle should be used to stabilize the caps."

 

I've installed an iron block and the only thing I'm worried about is traction at the strip.Moving the battery to the back should relocate about 35#s and you could also give up Big Macs for a yearRelocating 35#s from the front to the back is like adding 70#s as far as traction goes.As far as all around performance.#100s is 1/10th in the quarter or 1 car length at the end.You could make that up with a little more boost.On the street most times you let it go you only go for about 1/8th of a mile so you are looking at maybe 1/2 a car length as long as you hook.If you make a full 1/4 mile pass on the street you are
(Who me?Never)
Now an iron block with a rear mount turbo/turbos and relocated battery,you've got it all covered.I think iron blocks are a good deal for the money.
Just my 2 cents.

 

Go iron block.....its repairable if something goes wrong. I went forged LS2 in the beginning and ingested my ECS meth nozzle in less than 500 miles. Cracked the sleeve and the block. You cant just bore out the cylinder and fix the block...you gots to resleeve at least one whole bank of cylinders. Had it been the LQ9 it would be a bore and hone job and move on. If your pushing serious HP the iron block wont weigh you down that much....hell buy a Braille battery and knock off 15 lbs.

 

Not sure who told you that but that is not true.
I have sleeved less than a whole bank on LS1, LS6, LS2 and LS7 blocks and have had no issues.

Several of them making over 750-800 to the wheels.