Colonel

There's a HUGE difference in 725 HP and 725 RWHP. That might be 600 at the ground. You'll still need a ~200 HP shot of N2O to get you to 750 RWHP.

I'm never one to say that something is impossible, but 750 RWHP...even 700 RWHP, would be one heckuv'an expensive and very frustrating goal.

Out2GetU

Queso,

You never mentioned that it had to be a ls1 based motor, right? I will send you a PM. I know a guy that can build you a motor that will fit in your car that will make that, and I know a guy selling a motor that makes 900 hp. It should make 750 rwhp easy. Check you mail.

queso

Sounds like we've got two camps.

Camp #1 says blow it/juice it or it can't be done.

Camp #2 says it can be done but not on a LS1 bottom end. Prolly a 502 crate for a base and then build up top end. Question is: will it fit the 2002 4th gen f-body frame when it's done?

Here's the kicker. I just stumbled onto a $20K inheritance. It has no strings attached and I want to keep it like that until I can figure out the answer to the initial question (How do you get to 750RWHP?). This isn't merely rethorical. If it can be done naturally aspirated, I'd like to build it.

I'm looking to you guys to help put this recipe together 'cuz for sure, many of you know a hell of a lot more that I do (sincere thanks for the interest & help folks).

Does anyone have ideas about bottom end, crank, rods, piston combos that would server as a good base to a high compression top end?

Out2GetU

No 502, and it will fit in your car. I will send you a PM with my cell #, give me a call and we can go over the details of what it will take, and if you are really willing to make that step let me know.

RyanJ

Here's my question...why 750rwhp. Why not shoot for 1000fwhp. 1 kilo-horsepower sounds cool.

NO LS1 will get there NA. Go buy a 422 w/ a direct port...you will be where you want to be....WAY to much for the street.

redz_02

iTrader: (4)

if i had money to spend like that i would run a resleaved all bore 383, i just love the numbers on these all bores, plus they are a tad cheaper than the big strokers, and see how much boost i could put into it, maybe try to max out a custom made t-trim kit.

Hitman#1

iTrader: (1)

$20,000 isn't near enough to do it with an LS1 based engine. Not naturally aspirated it isn't.

Here's an idea for you. Why don't you contact Ken Duttweiler, and see if he'll take on the project. I haven't seen his name associated with an LS1 yet, so he may give you a break on a big power Turbo engine just to get back in the magazines with a newer engine crowd. Tell him you've got $20,000 to spend, and maybe he'll just charge you for the parts and not the labor just for the LS1 market exposure. IMHO it's worth a try. It won't cost you anymore than just a little time and a phone call.

Pro Stock John

iTrader: (34)

Figure that some of the N/A bruisers like Mikey and BeaSSt are making like 600rwhp or so, I'd think with CR5 heads, big throttle body, and a lot of compression like 14:1??? you could get there.

Car would not be streetable.

You are talking about 8 second power.

Hitman#1

iTrader: (1)

He could have 17:1 compression and he still wouldn't get there. Compression is one of those items that are covered by the law of diminishing returns. You make more power, but as you go higher, the gains become less and less.

Those C5r heads had better move over 400cfm of air for this to even have the remotest chance. 600rwhp is a LOOOOOONG way from 750. You guys that are wrapped up in N/A power have to have more realistic goals. There are easier and cheaper ways to make this kind of power. Just my $.02

BYBYC5

2 words
DIRECT PORT

queso

Thanks for the interest. Out2getU, I got your PM and I'm keeping your phone# handy, just in case.

Well, I'm dead serious. Budget stands at $20K, and it's sitting in the bank. But, I'm flexible if more is needed and for a damn good reason. I'm still collecting info and trying to get input from as many knowledgeable people as I can, before making a decision.

I insist on aspirated, cuz it needs to last and be low maintenance (don't want to be replacing motor, valves and sh*t every three months).

Hopefully, little or none of the money will have to go into the chassis, tranny+clutch, or rear-end. It happens I've have been building up the car already, but going in incremental steps. I'm only heads away from taking stock motor to it's bolt-on limit (car has FLP Longtubes, MTI C2 camshaft, Whisper airbox + K&N induction, SLP LM exhaust at the moment). By the time I get around to start spending the $20K on the new motor, I'll probably have already taken care of the rear-end and chassis.

That new motor capable of putting 750RWHP to the pavement is what I'm searching for. I don't want to rush it, nor is the money burning a hole in my pocket. I'm determined on taking my time and do it right. The car is a 2002 Collection Edition (the yellow ones) Trans/AM M6 and was purchased brand new, exclusively for this project.

This car is one of the last ones and it's gonna become something special.

Hitman#1

iTrader: (1)

I assume when you say "aspirated" you mean Naturally Aspirated?

As for a 750rwhp Naturally Aspirated power plant, low maitenenance is exactly what it wont be. You'll need a BIG spring killing solid roller, high compression, and you'll have to spin this engine to well over 8000 rpm. Think dry-sump oiling, aluminum rods, low-tension rings, big tube headers, etc., etc., etc...

You'll hate this thing if you're going to do any street driving. Very expensive parts maintenance...

66ImpalaLT1

If you want a low maintenance street machine I'd probably stick in a big motor around 500rwhp. I have never heard of a streetable, reliable NA engine of any kind over 600rwhp.

Chicago Crew UnderBoss

iTrader: (1)

I AGREE 1000% with the above statement. There is NO WAY you could have a ***** OUT RACING MOTOR like this and have it low maintenance. It would be the oppossite and nothing but headaches and a money pit.

I suggest you get ALOT more relistic about your goals and focus on big cubes 422 plus with direct port nitrous if you want those power levels and the most realiability out of the set up. ARE is selling their direct port N20 422 CID motor out of their SS for around 20K and i would focus on something like that which will give you all the power you can handle on the street N/A and when you want to go radical and go for an 8 second time slip simply fire up the direct port N20. Otherwise, go with an iron block bored 4.030 with low compression and set up to handle big BOOST via turbo or supercharing if you are really hung up on 750RWHP. Otherwise, you won't see 750 RWHP on a N/A LSX motor and if you must stay N/A at won't budge off your HP Goals then have someone build you a BAD BUT small block chevy, non-LS1, like a couple of builders here have offered. I know the MOROSO C5 that runs 8s on motor only is running a bad *** small block racing motor (non LS1/6 motor) and i have seen that bad boy yank its C5 wheels 3 feet of the ground and run into the 8s all day. Just don't expect this to be a street car and more than likely it would have to be a 100% dedicated drag car.

BEST OF LUCK TO YOU and move slowly, patiently, and GATHER ALL THE INFO YOU CAN!!!!

robertbartsch

...what about the More Performance Inc. natually aspirated 427 motor that is discussed in the November issue of GM High-Tech Performance?

It makes 725HP at 7,500rpm and 570 torque at 5,700rpm. No blower, No juice - just motor!

The motor is bored and stroked to 427CI; it has a 12-to-1 compression ratio and has a sheet metal intake, aftermaket CPU, aftermarket igintion, etc.

Chicago Crew UnderBoss

iTrader: (1)

YEAH ROBERT the more performance motor would be perfect for this guy but the only problem is that the more performance motor makes 725HP at the crank and this dude wants to make 750 at the rear wheels and its just not going to happen N/A on a LSX GEN III motor.

Realistically the more performance power levels is what he needs to shoot for in a naturally aspirated LSX motor and said motor will cost between 25 to 30K in my opinoin if you go to a major tuner like More Performance, MTI , ARE, etc!

Colonel

When you get to spinning them up high and making big numbers, there's a HUGE difference between FWHP and RWHP. 725 FWHP is not even a good start when your goal is 750 RWHP. Seriously, that's not even in the ballpark...heck, it's not even in the same town as the ballpark!

"Figure that some of the N/A bruisers like Mikey and BeaSSt are making like 600rwhp"

PSJ, someone other than me has made over 600 RWHP NA on a Dynojet? I haven't heard about that if that's the case.

B-MAN

You have one hell of a challenge comming your way if you think that you are going to achieve that kind of power out of a N/A motor with no nitrous.
Good luck to you in your endeavor.

Cal

iTrader: (1)

All this reminds me of a story I head about a guy that won the lotto in Cali: He won more money than you're getting, several million. His wife divorced him and took half of it, but he still had a couple million so he bought a Viper and did every mod to it known to man; I think he doubled the HP or something. Anyway, at that point the car was such a PITA to drive, he bought another Viper just to have around as a daily driver!

grb

We've pretty much done everything within reason to my C5R 427. The C5R .090 heads seem to be the best power maker so far. Mine will have longer intake runners and a straight shot from the MAF to the intake. I'll post some numbers when it's done. BTW - we are going with titanium valves because it won't be a daily driver but decided to stay away from a solid roller.