All,
I’m considering doing a few performance upgrades to my 1994. It’s a bone stock LT1 FX3 MN6 Z07 car. It idles as smoothly as a Japanese I4. I’d like to keep it that way. I drive this car every day to and from work. I would love the lope of a racecar on a racecar but not for daily driving.

Please advise me on the following:
1. Open air box + K&N.
2. TB by-pass surgery.
3. Roller cam, rockers, pushrods, etc.
4. Polish and port heads.
5. Replace heads with LT4.
6. Long tube headers.
7. Better flowing cats.
8. Ford 24# injectors.
9. MSD ignition and MSD replacement for the optispark. (Is that just a plug in direct replacement for the opti?)
10. BMW trany fluid in the ZF
11. Transwarp drive to replace standard warp drive. J/K
12. NGK Iridium plugs and thicker wires.

Thanks in advance.

 

If you want to have it idle smooth and not spend x anmount of $ for mods that won't give too much power... Sell it and buy a c5.

 

if you go with lt4 heads , you will need a lt4 intake. just port the heads you have.

 

Without going with a cam/head package or nitrous or a blower...
I would say port your LT1 heads, 1.6 rockers, a rear end gear swap and a good tune of your PCM would give you a boost in performance that you would really notice. You will see somewhat of a gain with long tube headers but not enough for the $$, They are really good for other mods. The shorties headers flow barely better then stock, but may be lighter and in ceramic coated could help with under hood temps. The stock system flows really well for those light mods. With these mods you should sound and idle like your stock Vette and should run with the LT4 (maybe a little quicker with the right gears) Let us know what you do and post results PLEASE!!!

 

You like a stock idle and a quiet car. Why do you want info on cams, headers and high performance exhaust? I don't think you will like the results. I installed 1.6 RRs and a better flowing exhaust and intake. I like the extra HP but it doesn't sound or idle like a stock C4.

 

Your list is gong to cost a fair amount of cash to do even if you will be doing all of the work yourself. Is the current motor to the point where it's going to need rebuilding??

#1 is easy to do and while it won't provide much in the way of power, it will sound nice.
2 is also easy but for a DD, it may not be worth it.
3 and 4 will require a lot of work to swap out the cam (it's already a roller) and your choice of cam will determine how lopey you want at the expense of driveability. You can go with 1.6 roller rockers for some HP increase.
5- why replace the heads if you are doing a port and polish? The factory LT1 heads flow decently if massaged. LT4 heads will flow even better but they are around $750 each assembled but without rockers.
6- long tubes will give you a power increase but you don't list a cat-back exhaust system?? A good cat-back system is worth about 10HP alone. LT1 shorty headers will do a good job too.
7-the factory cats flow pretty well and if you go with shorty headers, you won't need to replace the cats. Also some shops will question cat replacement if there is noting wrong with the existing ones.
8 the 24lb injectors may only be needed with a larger cam and/or more displacement. The stock injectors should support what you are listing.
9 MSD CD unit like a 6A or 6AL is a good add-on if you're going to run the motor to higher RPM's. Do a search on MSD Opti to see what others think about this piece for the money. It's $500 at JEG's; the MSD cap and rotor alone is $150
10 The "BMW tranny fluid" is a specific weight Castrol motor oil designed for certain BMW motors. It's OK for the ZF if you are putting heavy demands on the tranny but the stuff is expensive and I think it's only available at a BMW dealer and some dealers may even ask you for the VIN of your BMW before they sell it to you.
11 I saw that episode and it looked like transwarp drive was never proven. Guess Warp 9 is about all we're gonna get
12- I used the NKG Iridiums in my 92 and it got me a couple of MPG extra!! I also installed MSD 8.5mm SuperConductor wires.

The one thing you don't show is your location. Emissions testing requirements may cause you grief with the cam and heads. If you have to do a visual inspection, the long tubes could also be an issue along with relocated cats.

After doing all the mods you've listed, you are probably going to need a custom tune to make it all work together. You could see a drop in fuel mileage if you go too big on the cam so that needs to be factored in too.

 

Thank you all for your replies. As always this forum is simply the best.

I was interested in a cam only for the change to rollers not for changing the profile at all. I know now, thanks to c4cruiser, that the cam is already a roller cam. I don’t know the right way to ask this but here goes: What would I need to change out to make the valve train all rollers?

I meant to ask before about the difference between LT4 heads/intake and port & polish LT1. Based on your responses I’d stick with the LT1 and just have them massaged. If the stock exhaust will flow freely with this light weight mod then I’d not go with headers. Maybe I’ll run across someone selling his shorties someday. That would preserve the stock cats and cat location right?

I think I’ll start this project in March. By then I hope to have a used 80 series Landcruiser as an alternate daily driver.

In the near future I’m going to need to replace the slave cylinder in the ZF. I’ll read up in the Helms and see if it’s something I should tackle on my own.

Thanks again!

<EDIT> Oh I know you're right about selling it and getting a C5. That would be the practical thing to do. When it comes to this car I choose not to be practical though.</EDIT>

 

Install a set of Comp Cams Pro Magnum RRs along with push rods, guides and little stronger springs.

 

If you mean roller rocker arms, they are available but you will probably have to grind off the drip tabs on the underside of the valve covers. Not a big deal to do with a Dremel. Use either the 1.6 ratio Crane Gold, Comp Cams Pro Magnum, or Harland Sharp roller rockers. Some folks have installed only the exhaust rockers and that seemed to provide power increases.

The factory lifters are rollers and that makes for a quieter and longer lasting valve train.

Shorty LT1 headers will allow you to keep the factory cats in their original locations. There's not a lot of room under the car for relocated cats. Also, you can replace the factory resonator with an X-pipe for improved exhaust flow. The factory mufflers are somewhat restrictive but you can use muffler eliminators to improve flow and get a much better sound!

 

I would polish and port the heads and do the full aluminum roller rockers springs etc. The free mods are fine. If you need a tune-up go ahead with plugs wires etc. After that is done you can start making decisions on the exhaust.

 

I doubt youll get a quiet idle with a C4 especially modded. I dont think I have ever heard a quiet C4. Has anyone?

 

You sound like your on the right track to get what you're looking for. I'm sure once you get a taste of a little more power.....you will be in BIG trouble..just like most of us

 

[QUOTE=94z07fx3;1558235838]All,
I’m considering doing a few performance upgrades to my 1994. It’s a bone stock LT1 FX3 MN6 Z07 car. It idles as smoothly as a Japanese I4. I’d like to keep it that way. I drive this car every day to and from work. I would love the lope of a racecar on a racecar but not for daily driving.

Please advise me on the following:
1. Open air box + K&N.
2. TB by-pass surgery.
3. Roller cam, rockers, pushrods, etc.
4. Polish and port heads.
5. Replace heads with LT4.
6. Long tube headers.
7. Better flowing cats.
8. Ford 24# injectors.
9. MSD ignition and MSD replacement for the optispark. (Is that just a plug in direct replacement for the opti?)
10. BMW trany fluid in the ZF
11. Transwarp drive to replace standard warp drive. J/K
12. NGK Iridium plugs and thicker wires.

Thanks in advance.[/QUOTE

It sounds like you overstated your concern for a smooth idle and you didnt say anything about sound. To make some real HP, I would do LTs and free flow cats, some mild head work (LT4 heads are not really necessary), upgrade the ignition with a Delteq or LTCC (still uses a portion of the Opti), select one of Comp Cams new Extreme Fuel Injection cams (260XFI or even the 268XFI) with 1.6 ProMagnum roller rockers, Beehive springs, magnum pushrods and matching retainers, and a tune (PCMforLess is a good choice). If you dont go crazy with the head work and cam, the car should idle decently (not as smooth as a stocker but no worse than a stock C5 Z06). This should put you at about 400+ Hp at the crank.

I have Exotic Muscle (EM) LTs (1 3/4) random cats, Corsa Exhaust, a tune from PCMforLess, and K&N filter on my 95 LT1 6sp and it idles as smooth as it did stock (slightly louder). I just purchased Comp Cams 1.6 ProMagnum roller rockers, Magnum pushrods, Beehive springs, and matching retainers. Heads and Cam are next. Hopefully then, my LT1 will run with my stock Z06.

 

Now I for one based on what I've read, believe that the stock cat back system is rather non restrictive until you're trying to push more than 400 hp. I wouldn't worry about an aftermarket exhaust on your 94 at all. It's much different that what's on the L98.

Why not just go for the LT4 hot cam kit($550-$600) made by GM and sold by GM as well as places like Summit Racing which include the cam as well as roller rockers.

After that consider a set of long tube headers with which you will need a set of aftermarket cats such as RT high flow cats with these changes you car will not be much louder than stock but with the long tubes it's going to sound deeper and throater than stock.

The only change to my 95A4 Z07 FX3 is long tube headers and RT cats. The LT hotcam kit will come next Oh yea, mine's a daily driver.

Oh and if that's not controversial ....... I say forget # 1 & # 2.

 

It sounds like you want to accomplish pretty much what I did on my 94 vert. You can check out what I did and my results here:
http://forums.corvetteforum.com/show....php?t=1305555
Roy