67Riviera

Hello all, I recently picked up an all stock 1996 LT4, 144k, F45. Not pristine but in good shape, paid $6250. My goal is to build a car that serves as a combo DD/road rally/autocross car. The car that comes closest to what I think I'd like is the green LT4 built by Z07Josh over on LS1Tech.

Current issues that need to be addressed:

-Ball joints. I'm up in the air as to what I should do here. New ball joints or go with all new everything? The SPC control arms look good and seem to have a fair bit of positive feedback around the forums.
-Shocks. One front shock is leaking a bit of fluid. I don't care to retain the F45 system, but there seems to be a lack of consensus regarding replacing these with coilovers vs. DRM Bilsteins with new high-rate monosprings.
-Rear main seal. This one probably exceeds my skill level. I've familiarized myself with the process, but I've had some difficulty finding anyone willing to tackle it. My go to local guy doesn't want to take it on, and the dealership flat said they wouldn't do it either. I assume that it would make the most sense to do clutch/exhaust and maybe a ZFDoc short shifter at the same time. Any shop recommendations in the Pittsburgh/East Ohio area would be appreciated. [Update: Sun Chevrolet quoted me $900.00 labor and is willing to do clutch/exhaust with customer supplied parts. Anyone with experience know if this is a typical bill?]

Goals after these have been addressed:

-Power. I'm coming to this car from a lightly modded C6 with right around 400whp. I'd like to get at least that out of this setup. Reliability is a top priority.
-Brakes. I think it has 13" rotors (I'd go check but it's not in the driveway at the moment). I've heard good things about switching to C5 rotors along with a bias spring to even things out, would this improve braking performance significantly?

Those are the main points, more to come as things progress.

pologreen1

Well, enjoy the project. You could have bought one done the way you describe for about 7500-8K.

Cam, 1.6 rr's, headers, tune, etc will get you more power. Gears will help. I would do coil overs, I am not happy with vbp at all.

67Riviera

All the things I listed for 7500-8k? If I remember correctly, the LT4 build I referenced (Z07Josh) sold recently for 14k. Maybe I've been looking in the wrong places, but this was the cheapest LT4 I've ever seen that wasn't a basket case.

What cam are you running in yours?

96GS#007

You don't have FX3. '96s that had the adjustable suspension had F45 Real Time Damping. It's unique to 1996, the shocks are not rebuildable, and replacements are next to impossible to find and will be used.

If you want a friendly 400rwhp, you will need to think about a stroker....key being friendly. You can get there with a cam, headers, ported or aftermarket heads, etc but it'll certainly have an edge to it.

$900 to swap a clutch and replace a rear main seal is pretty good. An ace mechanic can do it in 4-6 hours but most will need a full day. Add in 20 years of wear/tear/corrosion and they are bound to have some struggles.

67Riviera

Any idea if the F45 parts would be worth selling?

I've looked at a few stroker build threads, none that I've seen have given out a number on what it cost. I know an engine build can be very subjective, but a ballpark estimate would be nice.

QCVette

It looks like a fun project.

Before you do the rear main seal, make sure that is really what is wrong. Frequently the LT1/LT4 cars leak at the back of the intake manifold and the oil runs down and looks like it could be the rear main seal. If it is the intake leak it is much easier and could be a do it yourself project (not that hard).

Good luck.

96GS#007

Here's the thread on my 383 build. On a Mustang dyno it was over 400 at the wheels, it was right at 450 on a Dynojet at the wheels, both of which are pretty consistent with the rules of thumb that are out there for a ~500-525hp (at the crank) engine build. Whether people believe the chassis dyno numbers or not, the car was damn fast and the engine itself had very mild street manners. It was built for street/track day use (hence the cam selection), and I enjoyed using it trouble free until I sold it in late 2012.

Like all builds, the age old rule of "fast, cheap, reliable.....pick any 2" applies. It was fast and reliable, but it was not cheap. This was a $10k build with me doing almost all the work (except some machining and short block setup). I also did the tuning. If paying someone for all the labor....add another $5k. If you want to reduce the cost significantly, reuse your old block, have the stock heads ported, reuse your old intake and port it, don't buy lightweight rods, go with cheaper pistons, etc. Excluding labor a decent stroker can be built for $5k-$6k. If it's still mild mannered, it'll be down about 50hp from the one I built. Go radical on the cam and lose the street manners and you can regain that power. Mine idled like a stocker and passed tailpipe emissions testing.

Regarding the F45 parts.....there does seem to be a small market for them and the people into originality will pay a premium. However, you'll likely need to be patient with the sale. As mentioned before, F45 is one year only so the audience is very small....I think a few thousand cars were so equipped.

96GS#007

This is a very good point. Run your fingers along the front and rear edges of the intake. It's not unusual to find dampness from an oil leak.

The intakes on the LT1/4 are dry....no coolant running through them. If you have basic mechanical skills, you can R&R the intake in about 90 minutes. No need to disconnect the fuel lines, simply remove the 4 bolts that hold the fuel rail and injectors to the intake and the electrical connectors from the injectors, flip the assembly backwards onto a towel on the windshield, remove the throttle body, a few misc lines and connectors (all easy to access in seconds), and then the intake bolts. Pop the intake off, clean everything really well, apply "The Right Stuff" to the ends of the block, install the new gaskets, and commence reassembly. Let the car sit overnight before starting. It really is as easy as it sounds.

67Riviera

Great advice, thanks guys. I'll check that first - I've also had someone recommend that I run dye through it so I can be sure where it is coming from.

67Riviera

I'm well acquainted with that rule haha. I won't say cost is no object, but I'm just fine paying for quality. $10k is probably a tad outside my budget for just the motor. I do like the sound of a radical cam, but I know most of those make their power higher up the band - I won't be drag racing. I wonder if it would be easier to piece together a new engine from used parts, build it, then drop out the current engine and sell it. I can do some assembly work myself, but I'll need a reputable machine shop.

Great build thread, a lot of the ones I looked at had broken image links.

QCVette

I wouldn't recommend that.

The LT4's are worth keeping. They have a lot of good things like higher compression, bigger valves, bigger head ports, bigger intake ports, roller rockers, better timing chain, stronger cam, better crankshaft, etc. Even if you are starting to build an engine, most of these parts can be used with better results than using LT1 parts/engines.

My $0.02

mtwoolford

first of all that's a nice car and the price was right.

now, how much of your money are you willing to let us spend? Hey, just asking....

pologreen1

Lt4= lt1 with a hot cam and rr's to get to 330 hp. The value is the build numbers not the power.

My cam is 296/302 .650 lift

My point is you can buy a built car for 8k, not an Lt4 but it's an lt4 not the GS with the LT4.

67Riviera

Thanks! I drove it from Baton Rouge back to Pittsburgh, so it's good to hear someone opine that I didn't get completely shafted.

My initial all-in budget (not including the car) is right around 10k. I went from a C6 to a C4 so I could do what I want without the exponentially higher cost of entry. That said, I've also eliminated a pretty hefty car payment, so I have no issue spending more over the long term to get it dialed in.

67Riviera

Numbers for numbers, which would yield the best power for the dollar, building an LT4, or selling the LT4 and building an LT1? Forgive my ignorance, I'm reading as much as I can - somewhat knowledgeable on LS platforms, but very new to LTx.

pologreen1

Car resale in mind then keep Lt4 stock. If not build it. Your lt4 is an lt1 for real with a cam etc from the factory is all. Do what you want.

Let your wallet be the judge how wild you want to go.

Either lt4 or lt1 need major changes to make power.

350 sbc as is with heads, cam ,headers, exhaust will get 425hp. Same parts on 383 becomes 500hp.

I did not buy my cars for future, they are just toys to me and I don't have to worry about hacking it up.

67Riviera

I don't particularly care about the resale value. I have other cars that might (hopefully?) gain value, but this one isn't it. Supercar-ish performance at brand-new Altima pricing is what I'm after.

67Riviera

At the risk of bringing up a polarizing topic, I'd even be willing to go a bit nutters and try running e85. I'll qualify that by noting that the only way I'd do that is if I could easily reflash between a 91/93 and an e85 tune. I don't see many topics addressing this in any of the C4 forums. I used to own a stock turbo stock internals Mazdaspeed3 that ran a 50% e85 mix at 360whp/390tq, so I'm somewhat familiar with its use, but definitely not with a Corvette, which I'm sure is very different. I know there are several C6 guys doing this, but most seem to be of the opinion that you don't gain much in an NA application.

mtwoolford

[QUOTE

Current issues that need to be addressed:

-Rear main seal. This one probably exceeds my skill level. I've familiarized myself with the process, but I've had some difficulty finding anyone willing to tackle it. My go to local guy doesn't want to take it on, and the dealership flat said they wouldn't do it either.

[Update: Sun Chevrolet quoted me $900.00 labor and is willing to do clutch/exhaust with customer supplied parts. Anyone with experience know if this is a typical bill?]

-Power. I'm coming to this car from a lightly modded C6 with right around 400whp. I'd like to get at least that out of this setup. Reliability is a top priority.

-Brakes. I think it has 13" rotors (I'd go check but it's not in the driveway at the moment). I've heard good things about switching to C5 rotors along with a bias spring to even things out, would this improve braking performance significantly?
[/QUOTE]


First off, except for dealing with removal of the C beam, and a slightly more cramped tunnel, replacement of the rear oil seal isn't any different than any SBC made since 1987.

But there is a significant amount of labor involved; and no a $900 labor bill does not seem excessive; it boils down to how much of the old stuff do you want to reinstall. Unless you're very concerned about (presumably) a small oil leak, I would put off that particular job until it was time to do the clutch also.

yes your car does have the J55 13 inch brakes on the front, which besides being larger in diameter are also thicker than the standard brake package. It's fairly cheap to replace the rotors (if needed) and upgrade the pads; aftermarket, even C5 brake conversions, are considerably more expensive. I'd hold off here until I felt I really needed a brake upgrade.

I had ZFdoc do a shifter mod on mine, and here's the best part, if you detach the entire shifter assembly, which isn't hard with the trans out of the car, he will rebuild the whole thing, (in addition to shortening the shifter). He did this to mine, and I can't say enough good things about how well it worked out.

If you want more power out of an LT4, start with cam and work out. The factory designed the LT4 Hot Cam to be a drop in for these engines, and the dyno tests from back in the day put LT4 engines so equipped well within the power levels you aspire to...and...this may or may not be an issue for you...but mine passed California smog without any problem.

The significant issues I had with my 96 LT4 which required immediate attention were:

rear spring delaminating; replaced it with a VBP spring, 480 inch pounds, they would only suggest a max of 500 inch pound for street driving; this was a significant increase over even a factory Z51 spring;

new tires (naturally);

new brake pads on the front;

all new U joints, six total;

key stuck in the ignition tumbler and the column was loose, replaced with a new OEM column;

new Opti...believe me someone got their money's worth, and mileage out of the old opti;

new water pump;

found some bad lifters in the rear of the engine, of course those cam lobes were trashed; hence the LT4 Hot Cam, new lifters, new timing chain and new seals for the timining chain cover.

bushings were original..read worn out...all new poly bushings for the rear end.

found the original MultiTech injectors to be leaking; replaced with new Bosch III injectors...this was mandatory;

But the real place to start, is as with any old car, is a complete filter (especially the fuel filter) and fluid change and a ignition tune up (at a minimum, rotor, rotor cap, ignition wires, spark plugs); clean the throttle plates and the idle air control valve; check all the vacumn lines, ESPECIALLY the ventilation harness for the opti (mine was cut and deteriorated) and the vacumn lines (mostly cruise control) in the vicinity of the battery.

I've done a bunch more stuff, but I think the above list is pretty representative of what needs to be initially addressed on one of these cars. I hope you enjoy your LT4 as much as I've enjoyed mine, and yes working on the beast is part of the enjoyment.

96GS#007

There is no way in hell that the HOT Cam gets him to 400 wheel hp which is what the OP stated as a rough goal.

In general, with tuning and stock heads we all ran around 330hp at the wheels with the LT4 and the HOT Cam, less on the LT1 cars. With head work that bumps LT4 cars to 350-360hp at the wheels. With headers, big time ported heads, a bigger cam, a lot of tuning, and an aftermarket exhaust, the best I saw out of a stock bottom end was ~380hp.

That last 20 will come from a cam that's not enjoyable on the street or from cubes.