What will the LT4 conversion actually put to the rear wheels? I know it is rated at 425hp. Want actual numbers or what i'm actually going to get.

ANyone have the conversion and what do you run for 1/4's?

 

I'am by no means sure on this but don't LT4 conversions (stock Lt4 heads, no porting) put down something like 300 - 330rwhp (depends on boltons) ? Personally, port your stock LT1 castings and add nitrous or a blower/turbo.

 

LT4s stock come with 330hp. the conversion is typically not a stock conversion. a different cam is added as a cam swap is necessary to make an LT1 an LT4. the cam thats usually included in the LT4 conversion kits is the LT4 hotcam. a ZZ9 cam works well too.

if going fast for cheap is the goal. modify your LT1 heads. if your building your engine in stages i would consider the LT4 heads simply because they will work well with any future mods.

 

when i purchased my z,it had a LT1 scanmaster box in the dash,the guy i got the car from really did'nt elaborate on its use? i mean i know it measures things going on in the motor but what exactly is it for? it also has a speedometer in it,,,,,thanks

 

Stock LT4's come with 330 flywheel horsepower. With the LT4 conversion kit (which comes with the hotcam) you can expect 330+ rear wheel horsepower with tuning.

 

The conversion gives pretty good power. Not the best bang for the buck heads and cam setup though. I haven't got mine tuned in perfect yet but I have been able to get a 12.7 @107 at Bristol with a DA of 2600.

 

i too am wondering about this myself..........................If they only make a little over 330 rwhp how can they advertise it making 425+ hp? I mean at a 15% drivetrain lose for an automatic 425 crank hp would be 361.25 rwhp.

So what does it really make???

Would you be better off buying the LT4 heads.....porting them.......then throwing in a better cam?? You could probably do all that for the same $$$$ and make more RWHP as well.

 

My LT4 coversion runs 109+ mph.....Only 12.99 with a 2.0 60's though. 325 rwhp on the dyno....

 

I think some of you guys are getting confused about two conpletely diffrent camshafts.

One is the stock LT4 cam. ( not much bigger than LT1).

The other is the LT4 HOT cam.

The LT4 HOT cam is huge compared to the stock LT4 and LT1 cams.

 

Yes, 425 is at the fly. MORE performance did a article on the conversion. It is a decent value but also consider the WHOLE package. Not only the HOT cam but also add the 1.6 RRs too. The ports are better on the LT4 than the LT1.

However, I also agree that it isn't the best bang for the buck. Lloyd Elliot or Advanced Induction can port your stock heads to flow much better than the LT4 heads then you can add a more aggressive cam versus the HOT cam and still be smog legal.