Hey folks

Im planning to pull my Stock 350 in favor of a zz4, what kind of HP could i expect from a zz4, with a superram and some SLP headders and a 6al ???

 

Why not just buy a cam and heads?

 

With the SR, SLP headers, good chip, new injectors, 280-320hp and 360-400ft/lbs.

I did the ZZ4 because my 91 had 145k on it and I wanted the 4 bolt mains, forged crank, PM rods, and all the other good stuff.


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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,ZEX nitrous,Walbro 255lph f-pump,Accel AFPR,Random Technology catback,!cats,and mutch more.

 

I thought the ZZ4 was worth 355 horse & 405 TQ, at least thats what it says in Jegs. With all those improvements, thats all the HP i could get ? It seems more worthwhile to go buy a used Ls1 for the price ??

 

I just posted this a little bit ago. This guy has dyno numbers and a zz4 shortblock:
http://www.eecis.udel.edu/~davis/z28/

 

a guy i know has a ZZ4, slp headers, and other mods in his 91 RS. i think his rear end and tranny are sort of dying but his best 1/4 was 13.9.

 

The same person that owns that web site with the ZZ4 dyno data ran a 12.01 NA with a ZZ4 bottom end and AFR heads and a HOT cam. The HP figures that Jegs shows are with a carb setup, because of the way the TPI flows it make giant TQ and not much HP but that doesn’t mean it's slow. With the setup you talked about you should hit a 12.

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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,ZEX nitrous,Walbro 255lph f-pump,Accel AFPR,Random Technology catback,!cats,and mutch more.

 

That's its "gross" rating, meaning no smog equipment, air conditioning, power steering, etc. The ratings you see on passenger car engines like the LS1 is "net" ratings, and that means the engine in the car in full street and smog trim. The bottleneck in a ZZ4 engine is the heads. They are the same as the Corvette L98, and their technology is over 15 years old. I'm only still using them because I got them for a great deal and ported them myself. The ZZ4 engine is great for a 13 second car, but if you want more, you'll need better heads and cam. In my car, I made 280 RWHP and 380 RWTQ. Adding an LT4 HOT cam and SLP 1 3/4" headers gained me the numbers in my sig. Now if I could just get traction I'd be in the 12's.



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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

So does it seem to be more cost effective just to rebuild the 350 in my car now, i mean it kinda seems a waste now to go for the zz4, im just not sure about all the diffrent combinations of heads, cams, plus the miniram, and headders, how can i possibly make good descisions about what to buy ??

 

kevin91z,

how is the streetabily comapre between the zz4 and the hot cam??? I am not going to use the l98 heads (I'm using some gm performance cast iron 64cc head shaved with thinner gaskets)... I am retaining all the emmisions components on my application as I have to deal with a two speed idle tail pipe test (and a visual, fuctional test) for HC and CO... if you have any advice on parts choices and info for the prom I would appriciate being pointed in the right direction...

zroc

 

The engine with the ZZ4 cam ran fine on my stock chip. The LT4 HOT cam required a custom chip, and thats when I got into my own prom burning. But it should pass emissions with no trouble, its just a matter of tweaking the prom.

 

A friend with an 88 IROC has a ZZ4 with a miniram, and runs 13.30 @ 109 mph. With the right chip tuning, he could pick up another 2 mph. ZZ4 heads and cam.