What's Next?
 

First, a little background - I'm a younger guy, raised in a die-hard Ford family. My dad always had Mustangs, most notably a '69 428SCJ Mach and an '08 GT500. When we got internet at our house my mom said I'd be punished if I went on any "bad" websites; my dad replied "That's right, if I find out you've been looking at Chevy's..." ... but I digress. Naturally I followed his lead and didn't pay much attention to much else until my friend got an LS1 a few years ago.

I recently bought that same car, a '99 Z28. The car has a lot of work done and I suspect it has nearly reached the pinnacle of natural aspiration but as I'm new to LS1's and, in fact, Chevrolet I thought I would get some opinions on what my next steps should be.

I had a bad experience with nitrous - 150 shot sent a rod through the block in my Cobra - and overall just wasn't impressed with what I got for the hassle so I'm not interested in that at this time. I am however interested in turbos and working on the bottom end. Do a lot of people bore/stroke these motors? What kind of PSI/HP can the stock bottom end handle?

Here is what I'm working with. I look forward to your suggestions. The car made 452rwhp.

Whisper Air Lid
FAST 92 Intake/92mm TB
36# Injectors
Racetronix 255lph Fuel Pump/Harness
Ported/Polished PRC LS6 Heads
MS4 Cam
Pacesetter LT's/Offroad Y
SLP Underdrive Pulleys
Centerforce DFX Clutch
Ford 9"/Moser Axles
LCA's
Torque Arm Relocation

You could safely add a 100-150 shot to that setup

Welcome. I miss my '04 Comp Orange Cobra badly but I don't miss agonizing over saving $1200 up for cam(S). Enjoying being back to the simplicity of pushrods for a while. :)

Honestly, that is a pretty stout setup for a N/A street car. Like stated above; nitrous would be your best bet to get in the 600+ hp range, and the magic stick cams take to the juice pretty well.

Thanks for the replies! I guess these bottom ends are pretty solid then?

i would make sure you have sfc's , & check if rocker arms upgraded. just my one cent.

Thanks! It does not have sfc's. I was told it has LS4 rockers.

i like my BMR welded sfc's; do you have a safety loop? aluminum or even carbon fiber drive shaft? can be expensive but lowers rotating mass. just brainstorming sounds like a fun ride now get out there and burn a rubber road to freedom! ps do you know if they upgraded the timing chain? (ls2 chain cheap upgrade when changing cam)

Midwest Chassis subframe connectors

UMI for whatever suspension pieces you're missing.

As for your power, I think you're good. I'd put a 92mm plate kit from Nitrous Outlet (Nitro Dave) and let her eat. 150 shot no problem.

Speed density tune or MAF tune? You might have another 5-10hp there going full 4" intake tract. Are you seeing 100kPa at WOT on the dyno?

Chime back in

It does have a driveshaft loop, stock driveshaft. Timing chain is stock as far as I know. What is the advantage of an upgrade? Simple strength?

Looks like SFC's are up next. What suspension parts do you recommend? I have never had a car with enough power to necessitate them. The car doesn't hook up at all right now (tires are shot) but I have been impressed with how well it handles wheel spin. No wheel hop and it never steps out at all. Its hard to tell when you're even spinning in 2nd and 3rd.

It's speed density. I don't have much info on the dyno (just the numbers) as it was done by the previous owner.

Thanks for your replies.

Do you have a ram air kit?

I don't have ram air, great idea.

If you want to keep AC, there's the chrs1313 AC version, sold through Speed Inc. They have a non AC version as well, which I had, that is HUGE.

There's other ones as well. I'm simply speaking of the one I'm familiar with.

You won't see any big gains unless you go with a shot of Nitrous or F/I. You could go with a FAST 102 intake manifold and 102 TB, and TSP 1-7/8" headers with TSP true duals and you'll see 15-30 hp gains. You also need new fuel rails and injector spacers to swap to the 102 manifold. Then sell the FAST 92/92 intake/tb, headers, an cat-back exhaust to recoup some of the cost. IMO, nitrous will be your best "bang for the buck" just spend a little extra time and money to make sure it's set-up right.

How large is the difference between the AC and non AC versions? I've been contemplating on ditching the condenser and going that route.

There is also the SSRA as well. That's what I'm running, and they make a AC and none AC version too

It's substantial. The non-AC version could suck up a small child, let's put it that way. :jest:

Performance wise I've read there's a very small difference between the AC and non AC versions, but like dr_whigham has mentioned the mouth on the non AC one is huge compared to the other