Okay, I am working out the upgrade plan on my Z. I finally have it running well (smooth idle at just under 1000 rpm and smooth acceleration) so it's time to start thinking about the finished product. What I want is a good street machine that can take (I don't need to walk away, just beat them) any stock domestic (Mustang Cobra/Steeda/Roush being my main target).

What I have is a bone stock TPI 350 with the auto tranny and stock rear. The exhaust is a cat back system, not sure which one. I know what I want to do for the rear and the tranny, but I'm not so sure about the motor. I'm going to go with 4.10 richmond gears in the rear. It's my understanding that I have a limited slip unit out there, so I'll probably rebuild it as I go to keep the wheels spinning. For the tranny it's going to be a TCI Holeshot converter (should stahl around 2800 RPM) and I'll add a manual valve body to enhance that.

With the motor, I have been looking around, and I guess the L98 is a strange beast to say the least. I'd like to get a head/cam combo so that it's matched, but I have yet to find one that is specific to the TPI motor.

I am also looking into a 150 shot of nitrous, but doing it with the motor is what I really want.

So what suggestions do you all have? Anything would be appreciated. I'd like to stick with the TPI motor, for some reason no matter what I own, I try to stay true to the production parts on the vehicle.

 

If you plan on keeping the stock TPI then well you are limited in cam choice, since the tpi really doesnt make any power above 4500 rpm. So that being the case i wouldnt go with anything bigger than 220 duration @.050. Heads are your choice, wouldnt go with anything above a 195cc runner tho on a 350 ci motor. AFR 195s are beastly, however if moneys tight vortec heads have mid lift flow like crazy and can be had relatively cheap. However once again ur TPI wont bolt up to it however SDPC2000.com makes a tpi intake for vortec heads. LT4 hot cam and u should be good. When it comes down to it the TPI will hold you back, its a nice daily driven thing cuz of how much torque it gets downlow but itll choke the cr*p outa ur motor up top.

 

I hate to say this, because it's only relatively true, but money isn't an object.

Will the TPI bold to th AFR heads?

With the heads and cam, will I be pushing enough power to be a decent street machine / weekend warrior? I don't want to go out and embarass myself by pulling up next to a steeda mustang and get ripped. I bring this guy up because he has been taunting me (don't they always taunt you when they are just driving by?) and I don't want to run him and get smoked.

Thanks!

 

If moneys not an object toss that TPI and get something else.

 

^Correct. If money isn't an object like you say, do these mods and I guarantee you will tear that Steeda a new a$$hole.
1.) Holley Stealth Ram.
2.) New set of heads.(your choice, I will leave this up to other board members to figure out)
3.) New cam. (again, your choice but I will leave this open to the other board members to figure out)
4.) FULL exhaust. Headers, y-pipe, some 3" tubing all the way back, no cat or if you NEED a cat get a Catco hi-flow race cat...
5.) Tires. Wider and stickier.

 

Okay, so:
Holley Stealth Ram - $300
Holley Twin 58MM throttle body - $400
Trick Flow matched Head and Cam setup - $2000

Exhaust is a given no matter what.

In all actuality, the price isn't that bad. The next question is, is it worth it? If I am pulling it down and replacing the top end, would it be wiser to go with a swap? Moreso, am I limiting myself by sticking with the L98?

 

If all you want is a weekend warrior,semi-close to factory appearing than a heads/cam setup is fine for you...Adding a good intake is even better but 4.10 gears in an automatic car is kinda overkill is you ask me but its your car.

How many miles are on the engine you plan on building? More than 75-100,000? I'd rebuild it,bore/stroke it,or get a new engine.

The L98 IS definately worth modding...especially when the TPI is taken off

 

Like Ricer Killer said, the L98 is DEFFINENTLY worth modding as long as that TPI comes off. Also how many miles are on it? I would rebuild it (actually come to think of it, I *did* rebuild my 305 when I decided to do some modding to it ) just to be on teh safe side

 

Keeping it simple and stock appearing can be really fun. I imagine keeping the stock engine where it is right now since it sounds like you worked hard to get it running correctly. I'd do 3.42 gears, new Posi, NEW built 700R4 trans, Vigilante 2400rpm lock-up 9.5" converter, 26X10.5X16 ET Streets or 255/50/16 ET Drag Radials(SWEEEET), and a 150 shot of spray properly tuned for spraying on every car encountered that looks pompus.

Off the shelf, simple, proven, GOOD parts. Headers, no cats, exhaust and a cold air kit, MAYBE minor portwork of the TPI parts if you get bored. 3.42 gears because a TPI car is breathing hard with 3.73's, let alone 4.10's. Same reson for the tight 2400 nitrous built converter. 150HP NX wet kit and TPI will make big torque at low rpm. More than enough to scatter an old stock trans and rearaxle. Maybe stock up on 1 or 2 more rear axles for when you break the current one. ET Drag Radials on stock rims will hook awesome and still not catch too many peoples eyes. Goodluck!..

And if money isn't an object..seriously...Have someone who knows what they're doing install something like a pump-gas, 600+ cube, big block with a big stage of spray, Deadenbear powerglide trans, 9" rear axle, Madman suspension out back, etc.

 

If money is no object, then LS7... but if we're being realistic a short runner intake, good exhaust, and a good head/cam package combined with the proper gearing and stall converter and tires of course and you'll be good. Just make sure that everything you get wants to operate in the same RPM range. That is a point that cannot be stressed enough.

 

This point CANNOT be stressed enough.

 

Okay, okay, okay....Money isn't an issue to a point. I'm not going to spend 20K on a musi rat motor, but with regards to a swap, buying a hopped up motor isn't out of the question. I didn't realize the 4.10s would be pushing it. In the past I had a 'bird with 4.10s that worked well, but it was also a carburated motor, and was built different I'm sure.

It sounds like a rebuild is the way to go, but AutoRoc has peaked my intrest with his post. The parts he suggested (headers, gears, transmission, n2o) can be resued after a rebuild.

If I were to go the route of adding the headers (probably true dual eliminating the cats since they aren't required here) upping the gears, replacing the tranny, and adding nitrous, will that get me to a place where I'm beating most stock rides? Not necessarily walking them, but staying in front. Once I get those upgraded, I can put together my rebuild parts. Having a sleeper is always fun, and having a third gen is a blast. Put the two together, and I think I'm in business!

Oh, and thanks guys, this is a great help to a 4x4 carb guy.

 

[QUOTE=DementedZ]
If I were to go the route of adding the headers (probably true dual eliminating the cats since they aren't required here) upping the gears, replacing the tranny, and adding nitrous, will that get me to a place where I'm beating most stock rides? Not necessarily walking them, but staying in front. Once I get those upgraded, I can put together my rebuild parts. Having a sleeper is always fun, and having a third gen is a blast. Put the two together, and I think I'm in business! [QUOTE]

To be honest, NO. You NEED more. Gears will only hold them off for so long until you run out of gear (due to having a auto tranny) and steam at 4500rpm (due to having a TPI intake). Nitrous? Ya.. sure.. if you go to the drag strip. Replacing the tranny? Not gonna do much.. a 4spd TPI is a 4spd TPI either way you go.

 

If you want exact parts, here ya go.

SLP 1-3/4" Headers+Y-pipe (NO AIR)
Ditch the AIR Pump+ pipes, run a shorter belt
3" or 4" Exhaust of your choice
3" QTP Electric cutout if you do 3" exhaust
3" diameter intake pipe with cone K&N filter(Ditch the stock snorkel)
Pro Built(brand) Limited Street 700R4 Trans(Tell Dana we said HI!)
Spohn Steel Driveshaft
Spohn Lower Control Arms
Spohn LCA Relocation Brackets
Driveshaft loop of some sort
Precision Industries 2400rpm 9.5" Made to order for nitrous use
Mickey Thompson 255/50/16 ET Street Radials
Nitrous Express GM EFI Wet Kit PN: 20920 (Pulls fuel from Valve on fuel rail)

Stock timing should be very safe with 93 octane but a colder spark plug and good ignition are reccomended. Going from 6 degrees base to 10-12 degrees base would work better off the spray also.


Funny how there are no engine parts but you're looking at over 5K. However, everything there would make the car quicker or it will help keep you from being stranded on the side of the road fromn breakage.

With a head/cam/intake swap, I don't reccomend anything mainly because if I did, I would also add in getting a Gen 7 DFI for tuning. Of all the local third gen cars that make big power, NONE use a stock computer.Everyone I know that tries to tune doesn't get very far. Way too many variables. One day I'd say do a monster cube, carb/spray combo, the next I suggest a RamJet crate engine with a 150 shot for the convenience factor. Ah well. Goodluck!

 

A company called Scoggin Dickey has tons of just TPI stuff. For heads and intake its a single part #. It comes with all the gaskets and bolts you will need. It converts you to Vortec heads. I would reccomend this and a HOT CAM KIT. The heads and intake are #SD8060RATPI. The cam kit is #12480002. Vortec kit= $1,269.95
Cam kit= $ 536.95
The cam kit comes with self aligning 1.6 rockers, cam, valve springs, retainers, locks, spring shims.
I would think this kit would add 80 HP.
The web site is SDPC2000.com