Hey all, I need some advice. I currently have a 97 Z (M6). I am tring to figure out if I should stay with my current Z-28 or trade it in and get an LS1 Z.
I know the LS1 will make alot more HP with bolt-ons and stuff. But is more worth to keep my current car to mod, with less then 2 years left paying on it? Or should I trade it in and get an LS1.

My goal is to have a Z with between 420-450+ RWHP, close to the same or more in TQ, and still be a stock block. Meaning not bored or storked. Thanks for any advice you all can give me.

 

well, like you said, an ls1 naturally makes more power, an seems to be a lil more fuel effecient. u can make both fast with bolt ons. i mean i've seen GMHTP magazine articles ith stock motored lt1's going 12.40's. of course they are pretty much race bound, but u get the point. i'd say it all comes down to money. if you're tight on cash, stay lt1 for a while. u can pick up some LS1 Z28's for pretty cheap now. I've seen the really nice ones with respective mileage go for $10-13,000, and then some 75k mile + ls1 cars go for $8-10,000. best thing to is not to rush into the craze of the ls1, cuz u can often trick yourself into thinking that a car is better than it really is. basically, don't stick yourself with a dud. i almost stuck myself with a dud, once i got rid of the iroc and cruised into the lt1 generation.

 

420 - 450 rwhp is pretty unlikely from either engine and remain streetable without a turbo or supercharger. You can get close with a 383 and ported heads but you can throw driveability out the window. How fast do you want to go? I am putting out about 320 rwhp and running 12.50's at 110 NA. 425 hp at the crank can put you in the mid 11's. That hp level is attainable from either engine and is really only in the heads. The LS1 head is a better head no question with its high port design, larger valves, 205cc ports, and 15 degree valve angle. To get power out of them, they take much less work than the LT1 head. If I were to do it again, I would go with a newer F body with the LS1. It is a better design all the way around- different head bolt pattern, better main caps, exhaust separated between intake ports, 15 degree heads, better intake and larger tb etc...That's not to say that you can't get power out of the LT1 though. Quite frankly, I am amazed at the power my engine is making with just a cam! My engine has over 100,000 miles on it!
The only problem I see for you is the fact that the LS1 will make you essentialy start over. Maybe you should re-think the power levels you think you need and how fast you really want to go.

 

My goal for time in the 1/4 is low 11s on motor. Then if I want faster then I will go to nitrous or a S.C.

 

Just going by your HP goals, your going to have to have a pretty wild LT1 to make 450 RWHP on stock displacement, and street manners are going to be out the window.

From what ive heard some stock headed LS1s are making near this, so with a mild heads and cam setup you could probebly be pretty close to your goal, and still retain some decent street manners.

 

Thanks for the info so far.

Would I be making around 420RWHP with this combo??

AFR 210 Heads
AFR Hydra-Rev kit (for extra insurance)
Matched LT4 intake
AS&M or Holley 58mm T-Body
GM Z06 M.A.F.
Custom Cam (similar to CC306 most likely)
GM (LT4) 1.6 RR
CC Cromoly Push Rods
CC R Roller Lifters
LT4 Timing Chain
Delteq ignitioin system
Custom Tuning

I plan on building a 383 motor down the road but it will be a couple years until then. So I to do what I can with my current engine.

 

all the bolt ons ported heads big stall and 4:10s and u only say low 12s for an ls1?...hmmm i think it would go a bit (meaning a lot) quicker

 

Mid 400rwhp is easier on a LS1.

230+ cam
Ported 5.3L castings (done by a good head porter not el cheapo)
bolt ons
full tuning

That's going to be the cheapest way to a lot of power. 450rwhp on a LT1 takes a LOT more than just heads, 230ish cam and bolt ons. Let alone that the LS1 has more TQ with 347 tuned cubes than a 383 LT1 will.


Bret

 

a stock cubed ls1 makes more torque then a 383????? what joker told u that

 

Do a search this topic comes up every month!!!

 

Some ls1's can hit very low 13's stock, so if you want a car that doesn't need many parts to get into the 12's there you go. LS1 with port and polished heads, LS6 intake, all bolt ons, A4 with big stall, 4.10s, etc. You'd definitely be around low 11's if you get traction.

 

couldn't be farther from the truth their are ls1's in my area makind 440rwhp and are totally streetable with heads and cam packages it is all in the tuning. heck my car is at 400rwhp and it is very streetable.

 

Ok, yea, 450 to the wheels and very streetable. Forget everything I said - I guess I don't know what i'm talking about.