Greg Gore

the LT5 is a special limited production piece so unique that you would only expect to find something similar under the hood of an exotic. I would think it makes little sense to hotrod one due to other platforms being more readily available at lower cost with more potential. For example, one could start with a 2001 or 2002 Z06 and build a 1000hp LS7 for it with little to lose if you mess it up.

84 4+3

I agree, 40lbs seems reasonable. What does a camshaft weigh and multiply it by 3. Even though the block is aluminum it was quite a bit bigger iirc.

There were shipping weights somewhere a while back for the full pallet weight... I would imagine the weight difference would be <100lbs GenI/II vs LT-5.

MatthewMiller

The heads are ginormous compared to OHV heads, and someone above mentioned 21lbs worth of head bolts (!). Then there's the big cam drive system on the front end, and that dual-runner intake is probably heavier, too.

Zak2018

But with all that, doesn't it look awesome? It looks so exotic. Very few engines are so nice to look at. It really looks like an engine you would find in an exotic car. Then it makes good power and even with the extra weight it's faster than the normal C4, C5 and even C5 Z06 it seems. I don't really need more.

But it was very interesting and educative to learn from you guys why the car is heavier and the ins and outs of it.

pologreen1

How much heavier is a callaway?

84 4+3

The intake is a big difference I think. I think the cooling system was larger too wasn't it?

Zak2018

What about the LT4? It's basically an upgraded LT1 right? Is it heavier than the LT1?

And can a LT1 be upgraded to LT4 and does it even make sense?

84 4+3

There should be no meaningful weight difference between the Lt1 and Lt4.

MatthewMiller

Now that you mention it, I'm sure the cooling system is bigger and holds more water; although I doubt that's counted in the "dressed weight" specs. And IIRC, the LT5 held 9qts of oil and it may have had a cooler as well. Just a number of little things tend to start adding up when you make a lot more power.

Zak, it was a hell of an engine for GM to sell, especially back 28 years ago when it first came out. And some folks here have punched them out to bigger displacement, ported heads, cams...the works. And those can get pretty righteous. Overall they are better cars than the LT1 and even the LT4, but not without drawbacks. The extra weight doesn't hurt it's acceleration very much, but it is a negative for cornering and braking, especially since it's mostly over the front wheels. Overall though it's obviously still a very cool and fairly collectible car.

As already noted, they should be within literally a few ounces of each other. They are the same engine, only a slightly different cam and slightly better ports in the heads and intake. As for upgrading, sure, you could slap LT4 heads/cam/intake on an LT1 and get the same performance. However, if you're going to go through that much expense and time, then it would make more sense to go further than that. You could easily make more useful power than the LT4 without hurting street drivability.

FAUEE

Ported heads, a hot cam and you're basically there of not a bit further. I dunno if you even need to port the intake.

Zak2018

I get it that the ZR-1 may not be ultimate track C4. I guess if that is the intent a standard C4 with a LS swap or a prep'ed LT1 would fair better. But as far as road C4s I think it's the ultimate one.

It is similar with the C6 it seems. In so many reviews I saw comments that the C6 Z06 was actually the better handling and balanced car and the ZR1 was more bonkers and fun.

About the LT4 it's looking like it's not a necessity at all to go LT4 then? How much power can be gotten out of the LT1 in NA configuration before it starts idling like an old race car and is not really streetable? I like smooth engines.

To be honest I would be more than fine if I could get the ZR-1's 405 bhp out of it. I don't think you need any more. To be honest you don't really need more than the stock LT1 300bhp. But you know...

FAUEE

The c6 zr1 was the top c6. Anything you read about the z06 being better handling or balanced or something like that is utter nonsense. The only advantage the z06 has is slightly lower weight, and a higher redline. You could argue it's more thermally efficient, but the c7 zr1 didnt overheat on tracks like the c6z does.

There are no shortage of 400hp lt1s that idle like stock. A h/c/I 383 would have no issues there. You could probably do it without the 383 stroker too.

Paul Workman

When it comes to driveability (i.e, smooth idle, stop and go city traffic, etc.) coupled with higher (NA) output, that is where the DOHC architecture advantages really begin to shine! Architectural differences and advantages result in significant WOT performance advantage (per cubic inch displacement) w/o sacrificing drivability or fuel economy.

Note: Just why GM has been so reluctant to extend their fabulous DOHC V6 performance to their 6.2L V8s...is a friggin mystery!!!

A 508 HP 5.7L LT5 with stock cams, TB, bottom end...tends to mitigate any weight differences.

cv67

Cant really tell much difference throwing one around its minimal.
Back then 3400 lbs was almost considered heavy for a car;today many sports cars weigh a whole lot more than that.
Never cared much for the FX3 system but as said it was more of a "bells and whisltes" car.
The windshield and ac compressor are supposed to be lighter to help make up for it. Those cars never seemed to catch on-expensive in the beginning and not many know about them/how to work on them today.
Remember more of them being trailered when new to shows than seen on the street. Bet those owners regret it today!

Zak2018

Ok. I never drove the C6 Z06 or ZR1. Was just going by reviews I have seen.

I'm getting the impression a LT4 is more of a novelty than a necessity over the LT1. Good to know.

Zak2018

Nice sound.

The impression I'm starting to get about the LT5 is that they are very complex engines ,difficult to work on and expensive to maintain and repair. If that's the case, is it really recommended to mess with them to increase power? Especially if parts availability is lower than with LT1s and LS1s. And given they are special things, which may be one more reason to leave them stock. I'm just asking.

Greg Gore

They make better collector's items than hotrods. Replacement engine parts can only be sourced from other collectors who've accumulated a stash and prices are high.

81c3

That isnt true. There are on line stores like Jerrys that sell pretty much every part you can ever need for the LT-5. Prices for some things are higher than what they would be for a regular 5.7 Chevy block....for obvious reasons... BUT, very seldom are there engine failures with the LT-5. I would encourage and challenge you or anyone else to do research and find out how many LT-5 engine failures there have been on this forum or the Net Registry in the last 3 years..... Also, once you become part of the brotherhood of the Beast, you will find that often times, they will just give each other parts for shipping costs.... I have never once had a problem finding a part I needed for the 92 LT-5 I had or the current 90 I have.

Zak2018

Oh really? I wasn't aware of that. That also might explain why the low price, considering all the car is and has.

OK. So that probably closes that door for me.

If I would buy a ZR-1 it would be to drive and not to be a garage queen. But driving and enjoying a car where you can find no parts for the engine is not really possible.

Dang! There it goes out of the door.

Zak2018

Ok, now you guys are just messing with my head!