LT4 Vs. LT1 - Auto-Trend Repairs and Service Information Forums

Administrator · $y$Op

LT4 Vs. LT1

Administrator · $y$Op

The diffrences between the LT4 Grand Sport and GM's LT4 Conversion Kit

Administrator · $y$Op

RE: LT4 Vs. LT1

Administrator · $y$Op

RE: The diffrences between the LT4 Grand Sport and GM's LT4 Conversion Kit

Administrator · $y$Op

GM Performance LT4 Conversion kit PART NUMBERS

Stellar007 · Member

I dont know that the new Edelbrock air gap manifold would flow as much as the original LT4. It seems that the portion that they hollowed out to make it an "Air Gap" would take away from the volume of air the box can store/intake. Thats just my thoughts. Anyone out there using the Edelbrock air gap? If so what do you think?

Date: 10:25 PM Mar 21, 2008

RE: LT4 Vs. LT1

Administrator · $y$Op

LT4 heads come on the LT4 engines only. Same with the red intake.

You can still buy the LT4 conversion kit but they no longer sell the intake manifolds. It kind of makes you wonder if the heads are not far behind! I mean if they run out of intakes, they must be getting close to running out of the heads. I should stock up but the price is still WAY up there.

Administrator · $y$Op

Also read this write up about the LT1 and LT4 intake manifolds. It sheads some more light on the subject.

http://autotrend.activeboard.com/index.spark?forumID=91042&p=3&topicID=14783164

SELLC · CERTIFIED POST WHORE

Whatever you do be careful about information you get on www.ls1tech.com we have found this forum to be very poor with regards to keeping factual information on hand. Just the other day someone there tried telling us that an LT4 intake manifold will work on LT1 heads. For the record this is NOT TRUE.

Big Angry Hillbilly · User

An LT4 conversion for the most part, is a waste of money.

You can make factory aluminum LT1 castings flow MUCH better.

The LT4 Hot cam is a DECENT cam, but driveability and the powerband SUCKS.

The valvesprings on the LT4 heads in the conversion kit are barely enough spring to maintain constant follower to camshaft contact at high RPM's.

I know a guy with a stock shortblock LT1 car, with worked LT1 alum heads and an aftermarket cam, in a 4400LB car, that runs 11.90's. This is with a JUNKYARD SHORTBLOCK and LT1 heads.

SELLC · CERTIFIED POST WHORE

I agree, the springs that come in the LT4 heads arent worth a damn. I do however dis-agree with what you are saying about the heads. Without spending a lot of time you would be hard pressed to make LT1 heads outfolw the LT4 heads. Then agian if you spent that kind of time on the LT4 heads, the LT1 heads would not hold a candle to them.

Just look at the cutaway's for both the heads. You can see they were made to allow more airflow.

I agree that more than enough power can be had from a properly built LT1, however do all that to an LT4 and you better watch out.

Big Angry Hillbilly · User

The main benefit of the LT1 over the LT4 is the powerband is drastically lowered, so you don't have to beat the piss outta the engine to make power.

SELLC · CERTIFIED POST WHORE

That sounds like moderation Hillbilly...

Are you turning a new leaf or something?

chandler330 · Rookie

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SELLC · CERTIFIED POST WHORE

What are these?

.xml?

Not so sure these links above are safe to click on... wish Rastus was still here, he loved clicking on this sort of thing.

Rastus · UNSTOPPABLE!

SELLC wrote:
What are these?
.xml?
Not so sure these links above are safe to click on... wish Rastus was still here, he loved clicking on this sort of thing.

LOL !

To answer the questions prior about the head comparison, there's really no straight answer, unless you have a vacuum device with instrumentation to measure flow...

The variables to flow are / will be port to valve size ratio, followed by determining at what lift of the valve, offers the best flow.

Intake manifolds for EFI are best sourced that have bell intake runners ( of equal length ) for each cylinder, whilst feeding-off a common plenum-chamber, that can have single or multiple throttle-plates.

The above set-up is a 50 / 50 blend of IR ( independent runner ) & plenum-chamber designs.

Full IR systems will have their own throttle plate per cylinder, & enhance low-end get-up-&-go dramatically, since each cylinder isn't fighting the other for close proximity to the throttle-plate in a plenum-design. And equal volumetric efficiency is experienced for each cylinder. Top-end power is enhanced too.

PowerStroker · UNSTOPPABLE!

Rex, how do you feel the 5.7 TPI compares overall to the LT1? I've heard people have had some dissatisfaction with the optispark and prefer having the distributor in the traditional place. Also how do you feel these compare to the Mustang 5.0? Having owned all of these you'd probably be a good person to ask.

SELLC · CERTIFIED POST WHORE

I guess I'd have to start by asking, why? Are you looking for or at a GM sports car currently?

In general the TPI is known as a GEN ONE, as they were the 1st year of the one peice rear main seal. GEN Zero was the 350 that spanned decades and came with wax rope style rear main seals, and then the two piece. GEN0 was mostly your 60's and 70's and were usually fitted with carbs... the real early ones got nickel treatment so they were very strong compared to the later G1 and G2.

TPI is not a bad setup, and has a really cool look... in 350 trim they had some power too (for the period)... but you have to be careful because they also made the 5.0 liter TPI engines and they look almost exactly the same. Lots of threads already in how to identify them.

The LT1 is a very limited engine and is considered G2 but most of them put out about 300HP or close to that due to their improved designs. The optispark is for sure more work than your regular distributor but it's only on the front of the engine to accommodate the F Body Camaro/Firebird's newer cab forward design. You can't get that look and still have a distributor in the back, the LT1/LT4 also in the 91-up Corvettes -- although the earlier C4 Corvettes also had the TPI engine too 88-90ish. They could allow for the distributor in the rear on the Corvette due to it's super long clamshell hood.

The Ford 5.0 engine is a really good design for the year, with lots of power right off the rip if installed in a lighter Mustang... the best part about the 302's were the fact there are LOTS of aftermaket support... bolt on's out the wazoo! But the 351W is also a nice powerplant too -- does not spin up like a 5.0 -- but has that flat powerband like a 350 Chevy.

I like them both! Out of the hole and up to the 1/4 mile the 5.0 Ford is a ripper... but once you get past about 100MPH, the 5.0 starts to fall off -- where the 350 is good until about 140MPH before it starts to lose it's breath. Sure you could install power-adders on both to fix this but 140MPH is cooking on a public highway... so unless you're at the track, it's not really something most people are looking for. Just for reference, Linginfelter was able to get a 1988 TPI 350 to 254MPH on a track with the help of some turbochargers! This back in the 1980's even!

https://autotrend.activeboard.com/t65228746/254-mph-sledgehammer-1988-c4-corvette/

So I guess I'd go back to my original question of, "Why do you ask?"

PowerStroker · UNSTOPPABLE!

I've been falling out of love with the Ford brand over, well, I guess the last 10 years. Now they don't make a single product that I want to buy. So I was curious about the path I didn't take. Curious about what the main competitor of Ford was making back in the days when I actually liked what Ford was producing. It's far too late for me to switch brands as a dealer technician at this point in my career. But I just was wondering what if I had taken the other path at the beginning. Would my life be easier now? And since you are fluent in the GM performance products of the day, and since you currently have a 5.0 Mustang and a C4 Vette, it seemed like a good way to answer my question. I've driven 5.0 Mustangs, and I've driven a 305 carbureted firebird. I've also driven a LT1 powered gen 4 F body which I think threw me back in my seat harder than the 5.0 Mustang did, but I was 18 at the time and can't really remember it that well.

And I'm looking to the future. I'm looking to a time when I no longer work for Ford and what kind of vintage toy I might want to add to my garage someday. Thank you for your answers!

Rastus · UNSTOPPABLE!

Yo,

You have skills PowerStroker, & it only takes a few-weeks to adapt to a new work environment. I'd go to Toyota if I were you. Generally speaking, the cars don't break, & the new water-powered car would be an enviable thing to learn about, & then fit an adaptor-kit to your 460 monster truck.

No fuel bill sounds good to me...

The job would be a walk-in with your history.

PowerStroker · UNSTOPPABLE!

It takes many years to learn all of the nuances of a brand if you want to play at the highest level. If I switched brands, I'd basically have to start over as a light duty technician. By the time I actually learned another brand and became as effective with their advanced diagnostic issues as I am with Ford, it would be time for retirement. I don't want to be the guy constantly asking questions, I like being the guy that other people ask.

Rastus · UNSTOPPABLE!

PowerStroker wrote:
It takes many years to learn all of the nuances of a brand if you want to play at the highest level. If I switched brands, I'd basically have to start over as a light duty technician. By the time I actually learned another brand and became as effective with their advanced diagnostic issues as I am with Ford, it would be time for retirement. I don't want to be the guy constantly asking questions, I like being the guy that other people ask.

Yo,

1. Generally at dealerships, you only work on warranty vehicles , generally less than 10-years old.

2. Swapping over is good, you start learning once again.

3. I've worked at a number of Dealerships & places that work on everything, & you learn more by default at the gas-station jobs per-se. You have no choice but to fix it.

4. You'll also meet new people too, some most excellent, some not -so-great.

5. If you don't like where you work, you can always move-on.

6. You can scale-down your tool-chest into an alround portable work-hourse, where only the regularly used tools keep working, not taking-up space.

7. This will set-you-up to work from home.

8. It seems that you need a change, but are too regimented. This is unhealthy. It's good to serve.

9. A place like Toyota is a retirement place, as the cars don't generally break. This means you can relax, focus on more important things whilst earning an income.

10. Your skill-set & knowledge will explode. This is unsettling & can be uncomfortable at times, but you will feel alive once again.

-- Edited by Rastus on Sunday 12th of January 2025 04:14:38 PM

SELLC · CERTIFIED POST WHORE

Toyota does indeed break... I fix quite a few of them here!

Not only that, the new V6 Toyota engine they released to replace the V8's is garbage and they are having problems with them to the point people are demanding recalls.

The only thing more pedestrian than a Toyota is you, Rastus.

PowerStroker would be a fool to walk away from his job and start over at somewhere like Toyota... not everyone is living on an island off their parents trust fund like you, Rastus.

Rastus · UNSTOPPABLE!

SELLC wrote:
T1.oyota does indeed break... I fix quite a few of them here!
2.Not only that, the new V6 Toyota engine they released to replace the V8's is garbage and they are having problems with them to the point people are demanding recalls.
3.The only thing more pedestrian than a Toyota is you, Rastus.
4.PowerStroker would be a fool to walk away from his job and start over at somewhere like Toyota... not everyone is living on an island off their parents trust fund like you, Rastus.

R1. Yes, at your place, not at a dealership...

R2. So PowerStroker might have something to do afterall !

R3. I doubt that.

R4. My folks are still alive. I made a shyte-load of money as a MEO at sea. But you know this already...Short memory...

SELLC · CERTIFIED POST WHORE

Wrong, Rastus!

A Toyota vehicle requires maintance just like ANY OTHER VEHICLE! Brakes, Tires, Oil Changes, Valve Cover Gaskets, Tune Up's, Timing Chain guides and tensioners, wheel bearigs, shocks, struts and everything else any other car requires! Toyota also has their fair share of recalls and "still new" problems -- I know you would like us all to forget about the Run-Away-Toyota's while they were still trying to figure out drive by wire.

Futhermore, trust fund babies don't have to wait for their parents to die in order to get structured payments from their parents interest... it's quite common... there is also nepotism, such that could allow someone who might not be quite a Captian to serve in a roll further down the trough -- where they get paid a shyte-load of money for being the kid of rich parents (ie: Hunter)... furthermore, most "REAL" Capitans of the sea will die at sea with a long grey beard -- a peg leg and hook for one of their hands... but you also have your daft bastards out there who don't know when someone is rattling their cage and get sucked up into their own game.

I'd put you somewhere around the latter. biggrin

Rastus · UNSTOPPABLE!

SELLC wrote:
1.Wrong, Rastus!
2.A Toyota vehicle requires maintance just like ANY OTHER VEHICLE! Brakes, Tires, Oil Changes, Valve Cover Gaskets, Tune Up's, Timing Chain guides and tensioners, wheel bearigs, shocks, struts and everything else any other car requires! Toyota also has their fair share of recalls and "still new" problems -- I know you would like us all to forget about the Run-Away-Toyota's while they were still trying to figure out drive by wire.
3.Futhermore, trust fund babies don't have to wait for their parents to die in order to get structured payments from their parents interest... it's quite common... there is also nepotism, such that could allow someone who might not be quite a Captian to serve in a roll further down the trough -- where they get paid a shyte-load of money for being the kid of rich parents (ie: Hunter)... furthermore, most "REAL" Capitans of the sea will die at sea with a long grey beard -- a peg leg and hook for one of their hands... but you also have your daft bastards out there who don't know when someone is rattling their cage and get sucked up into their own game.
4.I'd put you somewhere around the latter.

LOL !!!

R1. Whatever...

R2. No shyte !...The last dealeship I worked for, was owned by the Launceston Motor Group, & they had dealerships all around the state. We would have monthly meetings that discussed the efficiency of all the many & varied brands. Toyota was always 100% efficiency as professed by the general manager, Pete Brown. Take it up with him for further debate. His words indicated that Toyota was a cruisy place to work, since there was obviously limited down-time to get that efficiency month after month.

R3. Whatever...I worked hard, & I earned a shyte-load of money...And I have more coming too...I did indicate for you & or your son to take a job-at-sea, but it seems that a MB dealership (which is where I came from originally) was all he wanted, & what you wish to continue doing yourself. Too bad. I also indicated that the mines are great for earning big-bux, but you were too scared to take the jump into better fortunes for some reason. You wouldn't be in debt now for the rest-of-your-life if you listened, but laziness & lack-of-vision / incentive seem to be your modus-operandi sadly.

R4. To be honest Stellar, when my folks do pass-on someday, it will be a curse to inherit the wealth, as I'm so-well-off now. The added wealth rises me too high on the ladder, & I 'm forced to become a capitalist, like Mr.trumpdt...And who want to be like that ???...

Nb. Lots of typos from getting used to new lap-top.Wndows 11 is shyte.

-- Edited by Rastus on Sunday 12th of January 2025 06:33:17 PM