LT1-LT4 Modifications 1993-97 Gen II Small Block V8

What is a 355?

Thread Tools
 
Search this Thread
 
Old Apr 19, 2017 | 03:50 AM
  #1  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default What is a 355?

As the title says, what is a 355 and what exactly do you need in order to build it? I've been searching but haven't found a definitive answer on any forum, and I can only find 383 stroker kits on eBay.

Perhaps someone could take the time and explain this to me in layman's terms?


I bought my dream car - my Formula LT1 - because I wanted something to tinker with and spend some time on, and after countless hours (years) of browsing I think I have finally found what I would like to do with it, and that is to build a 355! I'm not talking about starting this build today, but somewhere down the line I would like to do it. For now I would just like to know what a 355 is and what you need for it. All info is appreciated!

I have zero experience of any kind of engine work and I haven't done anything like this before (well, I did Pacesetter LT's last year lol), but I bought this car with the intent of learning. My car is my hobby and I have been a car guy for as long as I can remember. Cars in general, and f-body's in particular is my life!

Looking forward to answers!

/E

Last edited by ErikFormula; Apr 19, 2017 at 03:55 AM.
Reply
Old Apr 19, 2017 | 04:18 AM
  #2  
myltwon's Avatar
TECH Addict
iTrader: (1)
 
Joined: Jul 2004
Posts: 2,965
Likes: 7
From: Palm Harbor, FL
Default

The bore and stroke on a stock lt1 is 4.000" x 3.480"

This means the diameter of the cylinder bore is 4.00" and the amount the piston travels up and down the cylinder is 3.480". A 355 is when you remove 0.030" from the cylinder walls for a rebuild but still retain the stock length of stroke. A 383 is when you remove the 0.030" from the cylinder walls but also change the crank to one that has a stroke of 3.750".

the reason why you don't see 355 kits really is because it just requires a larger diameter piston where as a 383 requires different pistons, rods, and crank.
Reply
Old Apr 19, 2017 | 04:43 AM
  #3  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by myltwon
The bore and stroke on a stock lt1 is 4.000" x 3.480"

This means the diameter of the cylinder bore is 4.00" and the amount the piston travels up and down the cylinder is 3.480". A 355 is when you remove 0.030" from the cylinder walls for a rebuild but still retain the stock length of stroke. A 383 is when you remove the 0.030" from the cylinder walls but also change the crank to one that has a stroke of 3.750".

the reason why you don't see 355 kits really is because it just requires a larger diameter piston where as a 383 requires different pistons, rods, and crank.
This is exactly the kind of answer I was looking for, thank you very much! So a 355 build only needs a larger piston? It sounds so easy, why go through all the trouble for that? What kind of gains will I see from it?
Reply
Old Apr 19, 2017 | 07:14 AM
  #4  
myltwon's Avatar
TECH Addict
iTrader: (1)
 
Joined: Jul 2004
Posts: 2,965
Likes: 7
From: Palm Harbor, FL
Default

Originally Posted by ErikFormula
This is exactly the kind of answer I was looking for, thank you very much! So a 355 build only needs a larger piston? It sounds so easy, why go through all the trouble for that? What kind of gains will I see from it?
truly 355s are done mostly for the point of rebuilding when the cylinder walls of a block become damaged to the point of needing to be enlarged to remove imperfections from the bore.

cubic inches increase the potential for power since more space inside the cylinder can equal more power with the proper compression ratio and supporting parts like a larger camshaft and better flowing cylinder heads. Changing the piston allows you to run a different design to influence the compression ratio like more compression for a naturally aspirated build or one using higher octane fuel or lowering the compression ratio for forced induction.
Reply
Old Apr 19, 2017 | 08:36 AM
  #5  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by myltwon
truly 355s are done mostly for the point of rebuilding when the cylinder walls of a block become damaged to the point of needing to be enlarged to remove imperfections from the bore.

cubic inches increase the potential for power since more space inside the cylinder can equal more power with the proper compression ratio and supporting parts like a larger camshaft and better flowing cylinder heads. Changing the piston allows you to run a different design to influence the compression ratio like more compression for a naturally aspirated build or one using higher octane fuel or lowering the compression ratio for forced induction.
Damn, I have learned more today than I have in weeks googling about 355 builds, thanks again friend!

So if I buy a LT1 rebuild kit with a new crank and some new larger (forged?) pistons, and a mail order tune, is that all I need? My car has 77k miles on the clock btw.

How much money are we talking about?
Reply
Old Apr 19, 2017 | 08:51 AM
  #6  
Shownomercy's Avatar
Man-Crush Warning
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Jun 2009
Posts: 3,196
Likes: 129
Default

Buy this before spending anything else
https://play.google.com/store/books/...FRZHDAodObYCoQ

Read it a few times, then start planning a motor build.
Reply
Old Apr 19, 2017 | 08:59 AM
  #7  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by Shownomercy
Buy this before spending anything else
https://play.google.com/store/books/...FRZHDAodObYCoQ

Read it a few times, then start planning a motor build.
Very nice, I definitely need that. I'll order it next week! Thank you!
Reply
Old Apr 19, 2017 | 09:07 AM
  #8  
craby's Avatar
Teching In
 
Joined: Aug 2013
Posts: 33
Likes: 0
From: Tokeland
Default

if lookin to get more power and you got long tube headers already then head and cam would be a good place to start. with 77k on the block it should be in great shape. that is as long as its not been abused. le2 head job from elliotts with a custom cam from him is a good path to take. if you dont have one i would recommend you pick up a factory service/shop manual for your year.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Apr 19, 2017 | 09:32 AM
  #9  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by craby
if lookin to get more power and you got long tube headers already then head and cam would be a good place to start. with 77k on the block it should be in great shape. that is as long as its not been abused. le2 head job from elliotts with a custom cam from him is a good path to take. if you dont have one i would recommend you pick up a factory service/shop manual for your year.
Yeah I've been looking at the LT4 hot cam kit since I bought this car so a cam swap is already part of the plan! The reason for the hot cam kit is because it seems to include everything that is needed.

After doing the LT's I swore that next time I do anything I will pull the engine, and if I do that I might as well give the block some love while it's out in the open. Thinking about it still gives me chills along my spine.. it took me 6 weeks to do the headers, not one weekend as the people here on the forum said lol!

Thank you for your answer, I will search eBay for a shop manual!
Reply
Old Apr 19, 2017 | 09:38 AM
  #10  
Shownomercy's Avatar
Man-Crush Warning
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Jun 2009
Posts: 3,196
Likes: 129
Default

Word of advise, stop looking for one stop purchases.
Reply
Old Apr 19, 2017 | 10:07 AM
  #11  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by Shownomercy
Word of advise, stop looking for one stop purchases.
Meaning?
Reply
Old Apr 19, 2017 | 10:23 AM
  #12  
craby's Avatar
Teching In
 
Joined: Aug 2013
Posts: 33
Likes: 0
From: Tokeland
Default

hot cam setup is not all that great. doing the lower end is not as easy as it sounds, lol, and can cost a pretty penny. check around your area machine shops and see what they charge to bore your block. building an engine, its not hard to spend 5k real fast. about 1700 bucks for elliotts le2 job, cam and port intake. probly lookin at about 2500 for these and the gaskets, 1.6 rockers, pushrods and various parts.
Reply
Old Apr 19, 2017 | 10:43 AM
  #13  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by craby
hot cam setup is not all that great. doing the lower end is not as easy as it sounds, lol, and can cost a pretty penny. check around your area machine shops and see what they charge to bore your block. building an engine, its not hard to spend 5k real fast. about 1700 bucks for elliotts le2 job, cam and port intake. probly lookin at about 2500 for these and the gaskets, 1.6 rockers, pushrods and various parts.
Yeah I believe you, but as I said before - this is not something I will start doing right away. This has been my dream car since I was 14 and I plan on keeping it for a long time. It's a never ending project to me!

First of all I'm gonna build the rest of my exhaust, and when that is done I will move on with the suspension (probably Koni STR.T or KYB AGX). After that I will move on with the body and rims. I'm about to be a father in a few months so the car is pretty far down on the list. ^^
Reply
Old Apr 19, 2017 | 10:59 AM
  #14  
craby's Avatar
Teching In
 
Joined: Aug 2013
Posts: 33
Likes: 0
From: Tokeland
Default

kool, being a dad is so overwelming at first. yah i picked up some used heads and found a new crate short block to build while i drove the car. once engine was ready i just switched engines, well engine and trans, picked up a nice setup from patc. it was about a year process but could have drug it out for more with no issue.
Reply
Old Apr 19, 2017 | 11:34 AM
  #15  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by craby
kool, being a dad is so overwelming at first. yah i picked up some used heads and found a new crate short block to build while i drove the car. once engine was ready i just switched engines, well engine and trans, picked up a nice setup from patc. it was about a year process but could have drug it out for more with no issue.
I was also thinking about having a spare engine on a stand that I could build while driving the car, and swap them when I'm done. A nice little project when I want to get away from the family for a few hours!

Anyway, thanks a lot for the help, and btw your car is badass!
Reply
Old Apr 19, 2017 | 05:39 PM
  #16  
myltwon's Avatar
TECH Addict
iTrader: (1)
 
Joined: Jul 2004
Posts: 2,965
Likes: 7
From: Palm Harbor, FL
Default

Originally Posted by ErikFormula
Meaning?
conveniently packaged kits, though not always, are usually underwhelming in quality or value. Unless you're looking at advanced inductions or lloyd elliot, pretty much all the LT1 "heads/cam" kits are pretty underperforming. The same can be said with alot of the rotating assemblies (pistons, rods, crank, etc.).

When looking at rotating assemblies stay away from cast cranks unless using a GM crank. Hypereutectic pistons are fine unless you're planing a lot of compression, forced induction (turbo/supercharger), or nitrous.
Reply
Old Apr 19, 2017 | 06:29 PM
  #17  
RealQuick's Avatar
TECH Junkie
iTrader: (14)
 
Joined: Feb 2004
Posts: 3,970
Likes: 15
From: MA
Default

Do a heads/cam swap as mentioned... 77k should mean the bottom end is in good shape and not in need of a replacement.

Doing a heads/cam swap will gain you alot of valuable experience in disassembly/re-assembly and how the motor goes together. Depending on the setup, you should end up between 350-400rwhp realistically, which will equate to a fun street car. Once you get bored with that, figure out the next steps. Some people move on to nitrous or forced induction (supercharger or turbo).

At that point, start considering what bottom end to run.
Reply
Old Apr 19, 2017 | 06:44 PM
  #18  
myltwon's Avatar
TECH Addict
iTrader: (1)
 
Joined: Jul 2004
Posts: 2,965
Likes: 7
From: Palm Harbor, FL
Default

Do a turbo setup, I hear a guy on here makes really bad *** kits.
Reply
Old Apr 19, 2017 | 11:29 PM
  #19  
ErikFormula's Avatar
Thread Starter
Teching In
 
Joined: Jun 2016
Posts: 23
Likes: 0
Default

Originally Posted by myltwon
conveniently packaged kits, though not always, are usually underwhelming in quality or value. Unless you're looking at advanced inductions or lloyd elliot, pretty much all the LT1 "heads/cam" kits are pretty underperforming. The same can be said with alot of the rotating assemblies (pistons, rods, crank, etc.).

When looking at rotating assemblies stay away from cast cranks unless using a GM crank. Hypereutectic pistons are fine unless you're planing a lot of compression, forced induction (turbo/supercharger), or nitrous.
Ah yes, now I understand!

Originally Posted by RealQuick
Do a heads/cam swap as mentioned... 77k should mean the bottom end is in good shape and not in need of a replacement.

Doing a heads/cam swap will gain you alot of valuable experience in disassembly/re-assembly and how the motor goes together. Depending on the setup, you should end up between 350-400rwhp realistically, which will equate to a fun street car. Once you get bored with that, figure out the next steps. Some people move on to nitrous or forced induction (supercharger or turbo).

At that point, start considering what bottom end to run.
After I'm done with the suspension I will start looking for a cam. Maybe even a complete H/C package from Lloyd. Can you swap the heads and cam while the engine is still in the car?

I forgot to mention that I live in northern Sweden so ordering parts are very expensive with import charges and all that. My Pacesetter LT's and y-pipe sat me back close to 500 bucks in additional charges.
Reply
Old Apr 20, 2017 | 05:01 PM
  #20  
leadfoot4's Avatar
TECH Veteran
20 Year Member
iTrader: (1)
 
Joined: Sep 2005
Posts: 4,621
Likes: 11
From: Webster, NY
Default

Originally Posted by ErikFormula
.... Can you swap the heads and cam while the engine is still in the car?
Yes. The head removal will be somewhat easier than the cam, because after you remove the intake manifold and valve train parts, the heads will then lift straight off. The cam is a little trickier, as the radiator and a/c condenser have to be gotten out of the way. The radiator isn't too hard, but you probably don't want to evacuate the refrigerant from the a/c system, so getting the condenser out of the way could be tricky. Keep in mind, the camshaft is basically as long as the engine is, so you need that much clear space in front of the engine, in order to remove it.
Reply



All times are GMT -5. The time now is 01:28 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE