LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

94 z28 stock lt1 to 383

Old 04-16-2019, 09:07 AM
  #1  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
94 z28 stock lt1 to 383

Hello all,
I am new to the whole car thing in general. I was a mechanic in the navy and worked on gigantic steam engines and turbines and all sorts of equipment on a nuclear aircraft carrier. My girlfriend is a super car nerd and basically got a 97 z28 as her first car, and now she has 3 and is a UTI graduate and a Mercedes Benz drive graduate (first female to graduate from drive) and knows everything there is to know about cars, except what I want to know... whether she actually doesnt know or is just a butt I dont know.
So my question is about my 94 z28 I just got about a month ago. The transmission was allegedly rebuilt 10k miles ago, and the engine is standing at 199966 right this second, trying to snap the pic of the big 200k! And I will hopefully have a good paying job starting next month, and I've been trying to compile my wishlist for this car.
I want to buy the monster in a box 4l60e ss kit rated at 600hp and rebuild this transmission,
I want to get a Ford 9 inch with maybe a 3.5-3.7 gear ratio, but I would like you guys to correct me if I should get something more appropriate,
I want to put either 17 or 18 inch rims, 10 wide on the back and probably 8 on the front,
And i want to convert my lt1 to a 383, and I am sure I can find a kit online, but I also want to know what size fuel injectors, what size spark plugs, what size fuel pump I would need with the kit to complete it, and what AFR would be best. (i also know that the heads need to be sent to a machinist along with the block so the cylinders can be bored i believe 0.030 over to 4.030 and all that, so I'm thinking of finding a engine shop nearish to me and paying them one price to rebuild it and do machining work and conversion as that will probably be cheaper than buying a crate engine and buying the kit and sending the heads and block off, I've read several forums so far and this is just my thought I could be wrong)
And I am also wanting opinions as to whether a blower would be appropriate. I dont want a turbo, and I'm not opposed to a supercharger because I love the look of a big blower, but they are really expensive and im not looking to race this car really, maybe take it to the track every once in a blue moon, but I want this to be my beautiful weekend car. So I want around 500 hp, not too much and not too little lol.
Any and all info/opinions/ideas I greatly appreciate. I have just completely sunk into the car world now, staying up until 3am watching all sorts of videos.

My 94 z28 beasty

Last edited by doritoboy100; 04-16-2019 at 09:29 AM.
doritoboy100 is offline  
Old 04-16-2019, 09:32 AM
  #2  
Super Moderator
 
Injuneer's Avatar
 
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 67,230
Re: 94 z28 stock lt1 to 383

Lots of questions, we'll try to help answer them. But first I'm going to move your post to a more appropriate forum, where you are more likely to get the help you need. “Drivetrain” is only for the parts that come after the engine - clutch, trans, driveshaft, rear axle.

To clarify one of your points - you indicate you want a “blower”, but would also be open to a “supercharger”, but prefer the blower. They are both the same thing. There are different kinds of superchargers, including centrifugal and positive displacement. Is that somehow related to your idea of the differentiation between a blower an a supercharger? As a general rule, centrifugal supercharger kits are readily available for the LT1, while a positive displacement (like an Eaton) would pretty much be a one-off, custom build.
Injuneer is offline  
Old 04-16-2019, 10:02 AM
  #3  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

Originally Posted by Injuneer View Post
Lots of questions, we'll try to help answer them. But first I'm going to move your post to a more appropriate forum, where you are more likely to get the help you need. “Drivetrain” is only for the parts that come after the engine - clutch, trans, driveshaft, rear axle.

To clarify one of your points - you indicate you want a “blower”, but would also be open to a “supercharger”, but prefer the blower. They are both the same thing. There are different kinds of superchargers, including centrifugal and positive displacement. Is that somehow related to your idea of the differentiation between a blower an a supercharger? As a general rule, centrifugal supercharger kits are readily available for the LT1, while a positive displacement (like an Eaton) would pretty much be a one-off, custom build.
Thank you very much! I actually edited the post before you replied and removed the blower/supercharger part and fixed it, I didnt mean to write it like that, meant to say "I'm not opposed to a supercharger because I like the way a blower looks but I'm not trying to build a straight drag car" lol, and I thought the drivetrain was the name of the engine and transmission bundled! But it makes perfect sense after you said it like that! Thank you. I told you I'm new at this Haha. But what do I need to do to move the discussion? And which would be more appropriate?
doritoboy100 is offline  
Old 04-16-2019, 11:00 AM
  #4  
Registered User
 
Join Date: Mar 2018
Location: Atlanta, GA
Posts: 19
Re: 94 z28 stock lt1 to 383

WHAT IS YOUR BUDGET?

I want to buy the monster in a box 4l60e ss kit rated at 600hp and rebuild this transmission,
Ok, good idea. The 4L60E is not exactly stout in stock form.

I want to get a Ford 9 inch with maybe a 3.5-3.7 gear ratio, but I would like you guys to correct me if I should get something more appropriate,
Why? Why not just build out the factory 10-bolt? Unless you're planning on making a drag car or something with loads of power, this is an unnecessary expense. People bag on the 10 bolt a lot, but built properly with good parts - they can take a lot of abuse. For the A4, 3.73 is a nice compromise between performance and hwy mpg.

And i want to convert my lt1 to a 383, and I am sure I can find a kit online, but I also want to know what size fuel injectors, what size spark plugs, what size fuel pump I would need with the kit to complete it, and what AFR would be best. (i also know that the heads need to be sent to a machinist along with the block so the cylinders can be bored i believe 0.030 over to 4.030 and all that, so I'm thinking of finding a engine shop nearish to me and paying them one price to rebuild it and do machining work and conversion as that will probably be cheaper than buying a crate engine and buying the kit and sending the heads and block off, I've read several forums so far and this is just my thought I could be wrong)
Or you can just purchase the entire engine, assembled from Golen. Karl Ellwein is pretty much the best LT builder out there, but I don't think he's building as many now. The rest of your questions all require proper selection of your cam and heads. Anyone that tries to tell you what injectors, plugs, etc before a cam has been spec'd is a fool. Get the shortblock built, and then go to Lloyd Elliot (http://elliottsportworks.com/) to get the heads and cam sorted out.

And I am also wanting opinions as to whether a blower would be appropriate. I dont want a turbo, and I'm not opposed to a supercharger because I love the look of a big blower, but they are really expensive and im not looking to race this car really, maybe take it to the track every once in a blue moon, but I want this to be my beautiful weekend car. So I want around 500 hp, not too much and not too little lol.
Crossing over into the forced-induction ballpark is an entirely different thing and your budget just doubled. At least. You can easily get 500 hp (crank) without going FI so you should carefully weigh the pros and cons of this decision.

You made no mention of a converter, and you'll definitely need a custom tune - preferably a dyno-tune.

1995_LR is offline  
Old 04-16-2019, 11:15 AM
  #5  
Super Moderator
 
Injuneer's Avatar
 
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 67,230
Re: 94 z28 stock lt1 to 383

HP GOAL:

First, you indicate you are looking for 500 HP. Is that at the engine's flywheel, or at the vehicle's rear wheels? The 4L60E/drivetrain will lose 15-17% of the power by the time it reaches the rear wheels. 500 HP at the flywheel is maybe 415 - 425 HP at the rear wheels. It is possible to make 500 HP at the flywheel without a power adder (S/C. turbo, nitrous) or increasing the displacement to 383 cubic inches. Making 500 HP at the rear wheels (~600 HP at the flywheel) is possible, without the power adder or additional displacement, but that isn't going to be a friendly car for the street.

Added displacement (383 ci) makes it easier to make HP, and provides added low end torque, The larger displacement, the milder the cam required (and the less radical a large cam feels), and fewer issues with surging, tuning, etc.. A S/C on a stock displacement 350 ci LT1 engine (but not stock internals) can easily make 500 HP at the rear wheels. Buddy of mine did a Vortech S/C on a 383 displacement and made 1,125 HP at the flywheel.

How fast do you want to go..... how many $$$$$ do you want to spend.

From personal experience, 425 HP at the rear wheels is a fun car to drive on the street.
Injuneer is offline  
Old 04-16-2019, 12:01 PM
  #6  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

Wow! So much I don't know! I will go ahead and cross off the FI route as I am not really that interested in doubling the cost (quick search proved that), and also to clarify my mistake, I am looking at 500 hp at the flywheel, not making a race car, just a badass car lol. I would like to spend $10k on this, less is better obviously, but this is my list that I'm going to be knocking out over a period of time when I start my career hopefully next month, so more is also okay.
I like the idea of building on the stock rear diff, I just read that the 9 inch is about the toughest you can get, but I've found that they are pretty pricey, so how would I go about upgrading this? Better aftermarket 3rd member with 3.73 ratio? Better Axles?
And for the engine I will probably end up buying a built one since mine has such high mileage, so for the crate engines should I be looking more for a Carbureted engine? To my knowledge they give about 10HP less than fuel injection, but I am finding a bunch of them from various sites and they are fairly cheap, from $6-9k. I also found an LT1 383 on Golen rated at 500HP for $7499 at https://golenengineservice.com/lt1-p...-block-engine/
And this is the long block, but the image has no intake and the specifications don't mention one. So my question about this is: will I need to get a new intake? could I use my old one? or will I need a carburetor for this? And would it be smart for me to have custom long tube headers made? I'm not sure if the 383 will have more exhaust than the stock lt1 and if new long tube headers would help that and improve performance.
Also: 1995_LR mentioned something about a converter, I don't know what this is. And would this be a necessary item for a crate engine, or only if I were to do the conversion to 383?
Thank you both so much!
doritoboy100 is offline  
Old 04-16-2019, 12:13 PM
  #7  
Registered User
 
Join Date: Mar 2018
Location: Atlanta, GA
Posts: 19
Re: 94 z28 stock lt1 to 383

$10k to do all of this will be a stretch unless you are doing some of this yourself.

Converter - torque converter. AKA stall converter. You're probably going to be looking at a 3200 stall, and a good one is about $700-$900. Yes, you will need one.

Rear end: New differential. I run a TruTrac and love it to death. Good gears (AAM is about the best) and new axles and bearings. You're looking at about a grand in parts and another $500 to assemble everything and set lash on the gear.

Engine: No need to carb it. The stock intake is 100% fine for what you want to do - and well beyond. If you get the heads and cam from Lloyd, have him also handle the intake. A complete port-matched system will knock your socks off.

You also make no mention of brakes. All that go-fast stuff needs to go-slow just as quickly.
1995_LR is offline  
Old 04-16-2019, 12:33 PM
  #8  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

Originally Posted by 1995_LR View Post
$10k to do all of this will be a stretch unless you are doing some of this yourself.

Converter - torque converter. AKA stall converter. You're probably going to be looking at a 3200 stall, and a good one is about $700-$900. Yes, you will need one.

Rear end: New differential. I run a TruTrac and love it to death. Good gears (AAM is about the best) and new axles and bearings. You're looking at about a grand in parts and another $500 to assemble everything and set lash on the gear.

Engine: No need to carb it. The stock intake is 100% fine for what you want to do - and well beyond. If you get the heads and cam from Lloyd, have him also handle the intake. A complete port-matched system will knock your socks off.

You also make no mention of brakes. All that go-fast stuff needs to go-slow just as quickly.
Oh! Torque Converter! Duh lol. Yes, Monster in a Box has the Thor brand I was going to get with the kit, I forgot to ask what stall I needed for the 383, and you answered that! Thank you very much for that!

As for the heads if I get them with the Golan crate engine they will be done up and pretuned I believe, so I guess all I would need is to have my intake done

As for the brakes, I am looking into C5 brakes, but yes I will do that as well as I do enjoy stopping Haha.
doritoboy100 is offline  
Old 04-16-2019, 12:50 PM
  #9  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

I found a 2800-3200 lock up one for 4l60e that's only $400, for the torque converter would it be recommended to go the extra mile and spend more on a better one? I dont know if this one is bad per se, but just want to get everything right the first time.
https://www.monstertransmission.com/...l#.XLYU2DcpCdM
I'm probably going to start with the rear end, upgrading 3rd member and the axles, upgrading the brakes, getting bigger wheels and tires and then I will save up and buy the engine and transmission rebuilt kit and torque converter, and have the intake sent off. Then I will put it all together at one time and throw it in.
doritoboy100 is offline  
Old 04-17-2019, 08:53 AM
  #10  
Registered User
 
Join Date: Mar 2018
Location: Atlanta, GA
Posts: 19
Re: 94 z28 stock lt1 to 383

A $400 converter will do little other than add a lot of heat to your ATF, and perform poorly. I have run a Boss Hogg (another $400 converter) a Yank as well as an Edge converter. The latter two were about $900, but both introduced less heat than the cheap one, and both performed almost like stock until romped on. I threw out the 3200 RPM stall based on my assumption that your cam and gear would be close to mine. Once things start being built, that may change. Your engine builder and your sales consultant from Yank or Edge can further guide you.

I would strongly suggest that you throw the brakes on and learn a lot more about what your options are and the implications of the choices you are making. A car is like a body - you can't change one part without affecting the whole so your choices need to be made from a holistic viewpoint. IE: increase the horsepower and you'll increase heat. This means you now have to upgrade the already crappy cooling system in the f-body. Increase stall speed and add heat, so you'll have to add a trans cooler. More gear means more torque so you'll probably have to upgrade your mounts, driveshaft, and brakes. More cam and heads means better exhaust. More cubes, cam and heads also means more air required and bigger injectors. All of those mean a custom tune is mandatory. Now that you're tuning, what else needs to be done to the tune? Lower fan turn on temps? Adjusted shift points and firmness? Less timing for a more conservative (city-friendly) engine? And down the rabbit hole you go. Since you're kind of new at the game, there is a LOT of potential to be relieved of money that you normally need not spend.

This forum is ok, but kind of dead. Go over to LS1 Tech and the LT1 subforum and do some reading, and then head over to the Impala SS forum and read some more. LTx Tech is yet another one - and Lloyd Elliot himself regularly posts there.
1995_LR is offline  
Old 04-17-2019, 09:17 AM
  #11  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

Originally Posted by 1995_LR View Post
A $400 converter will do little other than add a lot of heat to your ATF, and perform poorly. I have run a Boss Hogg (another $400 converter) a Yank as well as an Edge converter. The latter two were about $900, but both introduced less heat than the cheap one, and both performed almost like stock until romped on. I threw out the 3200 RPM stall based on my assumption that your cam and gear would be close to mine. Once things start being built, that may change. Your engine builder and your sales consultant from Yank or Edge can further guide you.

I would strongly suggest that you throw the brakes on and learn a lot more about what your options are and the implications of the choices you are making. A car is like a body - you can't change one part without affecting the whole so your choices need to be made from a holistic viewpoint. IE: increase the horsepower and you'll increase heat. This means you now have to upgrade the already crappy cooling system in the f-body. Increase stall speed and add heat, so you'll have to add a trans cooler. More gear means more torque so you'll probably have to upgrade your mounts, driveshaft, and brakes. More cam and heads means better exhaust. More cubes, cam and heads also means more air required and bigger injectors. All of those mean a custom tune is mandatory. Now that you're tuning, what else needs to be done to the tune? Lower fan turn on temps? Adjusted shift points and firmness? Less timing for a more conservative (city-friendly) engine? And down the rabbit hole you go. Since you're kind of new at the game, there is a LOT of potential to be relieved of money that you normally need not spend.

This forum is ok, but kind of dead. Go over to LS1 Tech and the LT1 subforum and do some reading, and then head over to the Impala SS forum and read some more. LTx Tech is yet another one - and Lloyd Elliot himself regularly posts there.
Thank you very much, very knowledgeable. I do understand the holistic standpoint and know that every action I take will have reactions elsewhere, and that's why I came here in the first place, to understand what the elsewhere contains. I am going to put a ton of research and thought and time, and hopefully just enough money into this that it's perfect for what I want.
Thank you very much for the links, I'm going to continue reading more on those forums. I've read some of every section on this one already.
doritoboy100 is offline  
Old 04-17-2019, 01:09 PM
  #12  
Registered User
 
Join Date: Feb 2019
Location: Iowa
Posts: 18
Re: 94 z28 stock lt1 to 383

My $0.02,
Do the rear end & gears/tires first. Easy to spend money here. I've not had good luck with the 7.5 rears but others have, YMMV.
Grab logging/tuning software like eehack/tunerpro and DIY the speedo/trans calibrations. Get familiar with the software.
Install trans temp, oil psi, and WBO2 gauges
Make sure brakes/suspension are up to snuff then worry about upgrading the drivetrain $$$ etc...
Read lots.
Rhansen is offline  
Old 04-19-2019, 08:13 AM
  #13  
Registered User
Thread Starter
 
Join Date: Apr 2019
Location: Warrenville, sc
Posts: 24
Re: 94 z28 stock lt1 to 383

Originally Posted by Rhansen View Post
My $0.02,
Do the rear end & gears/tires first. Easy to spend money here. I've not had good luck with the 7.5 rears but others have, YMMV.
Grab logging/tuning software like eehack/tunerpro and DIY the speedo/trans calibrations. Get familiar with the software.
Install trans temp, oil psi, and WBO2 gauges
Make sure brakes/suspension are up to snuff then worry about upgrading the drivetrain $$$ etc...
Read lots.
This is exactly what I want to do. My main goal for the start is convert front brakes to c5 (and eventually all 4) and replace the shocks and springs, as it's a 25 year old car and I know it needs them lol.
I want to put 17 or 18 inch rims, 8 inch wide on front and 10 on back, but that can come later as I'm sure I'll spend over 1k on rims and tires.
I want to rebuild the transmission with the monster in a box kit and go ahead and do a shift kit on it while I have it apart and I feel like that alone will increase performance, as I'm having some negative thoughts about this transmission right now. When I get up to 50mph i hear what sounds like a shuttering sound, and when I let off the gas it immediately goes away, and when I am on the brakes slowing down coming to a stop light, right when it finally stops theres a clicking noise, the only way I know to describe it in words is that it sounds like plastic cracking I guess. Just one click though. And twice now it has slammed into reverse, and then it does it againwhen I go back into drive from that reverse.
So I just wanna make sure it's done right, he said it was rebuilt 10k miles ago and he had to have him do it twice because it wasnt running right the first time so my guess is crappy mechanic.
So my next questions would be: aside from rims tires brakes suspension that I plan to do, would I need a new torque converter when I rebuild my transmission (monster site says I do, but if I'm not increasing engine power do I really need one? And if so what stall would be best for stock lt1, and non lockup or lockup? I don't fully understand the stall/lockup parts. I believe the lockup would be better for heat reduction, but worse for top speed and gas mileage. Please correct me though.
And lastly, what should I do exactly as to upgrading my rear end? I'm sure I can leave it as the stock 7.5 10 bolt for now, but I know I'll need a stronger one for a bigger and badder engine, so would I have to completely change the rear end to change to either a 12 bolt or to a Ford 9 inch? Or could I just get pieces parts, like get better axles and the gears themselves and then a different housing? I doubt it just looking at them.
Thanks again. Sorry for having a lot of questions, and I'm trying to answer them myself with research, I just have little time right this moment as I'm working full time and in school full time in evenings so just asking for general information from you guys first.
doritoboy100 is offline  
Old 04-19-2019, 09:00 AM
  #14  
Registered User
 
Join Date: Mar 2018
Location: Atlanta, GA
Posts: 19
Re: 94 z28 stock lt1 to 383

The best method in building a car's driveline is back-to-front, so you are on the right track. The 7.5" is unfortunately a grenade when pumping anything more than 400 tq. Why they put that POS in the Z is beyond me. Luckily, us ImpySS/Caprice guys got the 8.2 & 8.5. There are options other than the 12 bolt and 9 inch. The 10 bolt 8.x is stout.

Here's a good, but pricey option that is bolt-in:
https://www.hawksmotorsports.com/haw...-end-assembly/

The Ford will be even more expensive. They are cool though with the fast ratio-changes.

I would not bother with the stall selection until you've got the engine sorted. Ideal stall speed is a combination of your engine's powerband and your gear.
1995_LR is offline  
Old 04-30-2019, 09:34 AM
  #15  
Registered User
 
Join Date: Jun 2003
Posts: 862
Re: 94 z28 stock lt1 to 383

doritoboy...

you have a long list.

Golen makes a good motor. I bought a 383 4 bolt forged short block from them and have about 35k mi on it now. Call them and speak with Chad about your goals.

Have Lloyd Elliott do heads/cam package and port match the intake.

Tuning....need to source someone. There are still a few ideally someone on this site can recommend. I used Ed Wright but not sure if he is still doing them anymore. If so it would be mail order as I know he sold his shop years ago. Your tuner will advise on injector size based on what cam/heads you go with. Likely something of 30-36 lb

Gearing. For a A4 3:73 is as low as I would go. If its not going to be a drag car than 3:43's would get you lower RPM's at FWY speeds. There are online RPM calculators you insert tire size and rear gear and tranny 411 and it will give you RPM at x speed

Torque converter. Absolutely replace if rebuilding the tranny. Stall will depend on cam selection. Don't cheap out on the stall. Get a good one. Edge and Vigilantly have good reputation. Absolutely plumb in a external trans cooler.

Rear end...the 7.5" is fragile behind power AND hard launches with a tire but for just driving it will hold up. Obviously going 9" will be a huge upgrade but if you are not going to drag the car the 7.5 should hold up
Chimera96 is offline  

Thread Tools
Search this Thread
Quick Reply: 94 z28 stock lt1 to 383


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.