Tom400CFI

Yeah? yeah?? Well...your car is not "BAD TO THE BONE!"...like that LS6 in the vid says it is!


I agree w/the posters who said that you buy the LT5/ZR-1 for emotional reasons...not practical ones. I'm "bullish" for the ZR-1 in that regard. Most of us have a Corvette for emotional reasons...not practical ones. *I* HAVE a C4 for emotional reasons, not practical ones. As most may know, I had a C6, didn't like it, now have a C4. Practically speaking, or functionally speaking, the C6 out did the C4 in every objective measure (except gas mileage). If numbers is all you care about, the C6 is a WAY better, number producing robot.

The C4 is more fun to own and drive. If my C4 had 100 more HP, and 100 more tq, it would be a lot more fun. That is (almost) a ZR-1.

It's a personal thing, but *I* would chose a ZR-1 before a C6 because of the unique and interesting experience that the C4 ZR-1 provides.

.

Lloyd Smale

I wont argue that a ls isn't superior to a gen 1. But take a gen one put on the best heads sold for it. A modern roller cam and a computer controlled injection system to keep it running smoothly and your going to probably make within 25-50hp of an ls motor with a liveable idle and street manners. The main reason you get the gas milage and nice smooth running car is that computer on your firewall. It keeps timing at an ideal setting and your fuel air ratio perfect at all times. No your not going to get there with a holly carb and a single plane manifold and a roudy cam. you may get the power but your not going to get the streetability. My point is that when your comparing the ease of them making power your overlooking technologys other then the motor.

I measure a motor by hp per $. There an ls motor kicks but. They already come with a more advanced electronic package then the zr and the gen one comes with nothing. If you put a gen 1 carbed car a zr1 stock and an ls9 stock in front of me and gave me 2k to spend id bet a dime to a dollar the ls9 would be the hp winner. Same goes at 1000 bucks or even stock. But given enough money you can even make a ford fast! Another advantage to the ls is its going to make that power at a lower rpm. take two motors spin one at 6k and one at 8k and odds are the 8k motor is going wear faster.

MavsAK

Sorry but the SB2 isn't an SBC, no matter how hard you pretend it is.
Also, you do realize that racing bodies require engines of a specific type to be run right? You don't get a choice between LS, or SBC for your cars.
And that "article"

I suggest you step your education up.
1308 hp, on STOCK INTERNALS, right down to 160,000 mile rings. You aren't doing that on an SBC. Period.

Oh by the way, that was with ported versions of stock heads too, and stock displacement of 326 CI. It made 500 horses, with just a cam, porting the heads STOCK valves, lifters etc, headers by the way.

But hey, keep dreaming that the SBC is > the LS

Nah, GM totally put the LS in because it's inferior, and totally races with the LS platform because it sucks And everyone that's unbiased about engines, swaps the LS in because they want to gimp themselves.

1993C4LT1

Sorry 5abivt, but your z is dope

billy mild

If you think GM went with the LSx over the LT5 because of it being overall better, do your research. They didn't like the LT5 due to it not being a true "GM" design. Also they would have to make the newer vette models a little larger.

You can't compare a handbuilt LT-5 vs. mass produced LSx engine, from a cost standpoint.

pushrod-v8

No it doesn't.

It's $10K

http://www.zr1specialist.com/HAT%20W...20upgrades.htm

Still expensive compared to a traditional pushrod-v8 motor.

bb62

This is a true statement assuming everything else is equal. The problem is that all things usually are not equal. Chevrolet engines (and most competitive engines) suffered going into the 80s with tooling that was creating engines with bores that were generally out of round. This was cured by both GM and Ford by the introduction of CNC (Computer Numerical Controlled) boring facilities that supported the new engine architectures. This was one reason why engines of the 60s neither delivered the quality nor the power of their descendants. Another reason why a later engine spinning at 8k can last longer than an earlier engine at 6K is the high tech surface coatings found in the newer engines.

Interestingly enough, the one manufacturer that produced engines that were statistically in spec throughout the 80s to much higher levels of tolerance was Porsche.

JrRifleCoach

Your quoting the 510hp

I was quoting the 550 hp version

Lloyd Smale

true enough but the comparison here is between the lt5 and the ls motors and the ls motors are machined every bit as well as the lt5s and turn less rpm. Even by the time the c4 came along motors were no longer 80k propositions. Many l98s made 200 even 300k.

Paul Workman

This thread has been a good exercise, regardless of whatever opinion one has kept up to this point.

Performance aside, one of the undisputed attractions to the ZR-1 is its uniqueness; and the same could be said about the C4 GS as well. Just how much that is worth depends on the individual making the purchase. And, to be honest, buying any Corvette has that same appeal; to have something special, something unique among car owners. (In the day before the automobile, it was having a special horse...and still IS, among horse lovers!) It is a personal pride thing; to possess something special and (frankly) to show (whatever) off to one's peers, beit Corvettes, 4x4 pickups, or a stamp collection....

So, I ask myself: what besides being a Corvette was so attractive about the ZR-1 that people would pay practically double (or more, depending on the dealership) for this thing called a "ZR-1"? What particular aspects(s) was so unique to justify double the base cost then and now (relatively speaking)? Was it performance or because it was distinguishable as something unique...or BOTH?

At its introduction - well, it was both! It was unique especially when first introduced, on so many levels; both in its unique body design and performance wise which eclipsed the European cars in its class as well.

I don't believe that uniqueness was lost on GM marketing. However, the ZR-1 was beyond the traditional Corvette buyer's wherewithal, but unique does sell, on that there was no argument. So, (referring to Anthony Young's book, "Heart of the Beast") within GM the marketing group had reasons to mitigate the gap between the base Corvette and the ZR-1, and as Dave McLellan has said many times, the LT5 tweaked the noses of the engineers at GM Powertrain, instilling some personal incentives to come up with the power plant that would dethrone the LT5.

In their quest to mitigate the ZR-1's uniqueness, the marketing department first dealt a heavy blow to the ZR-1 in 1991. By adopting the rear fascia look they had removed the one distinguishing feature that up to then said, "ZR-1". That was the first nail in the ZR-1's coffin.

In the mean time, GM Powertrain engineers were desperately cooking up an SBC gen II which was clearly intended to at least narrow the hp gap between the L98 and the LT5. (As Dave McLellan has said in so many words, it (the LT5) got the engineers off their hands to come up with some real horsepower.) It was the combination of incorporating the ZR-1's distinctive body cues AND teaming with the engineers on the introduction of the LT1 that put the second nail in the LT5's coffin.

And, in case you don't remember your history, there was an economic down-turn in 1991 that culminated in the election of Bill Clinton who campaigned on that fact. (Remember Clinton's campaign adviser, James Carville's infamous slogan: "Its the economy, stupid!") Coffin nail #3.

The combination of marketing and engineering's concerted efforts to mitigate the distinction of the ZR-1, combined with the the economic slump making people reign back on extravagant expenditures especially, had taken their toll on sales numbers such that the LT5 project was cancelled in late 93 in spite of a 30 hp increase (to 405). The decision was made to spread the ZR-1 production out, using the remaining inventory of LT5s on hand until the C5 became available, or the supply backlog was exhausted. (This was in spite of the fact Mercury Marine had developed a gen-II of the LT5 that made over 475 hp. By then the C5 design was pretty well set with the smaller LS1 motor in mind to meet the performance and emissions hurdles Corvette was facing.

And there was more... Re-certifying another new LT5 for emissions and OBD-II compliance was just too insurmountable for financially strapped GM and its bean-counters. So, in spite of its stellar, record-setting performance, through no fault of its own, the legendary LT5 program was scrapped (save for the Northstar and a smaller version of it that powered the Aurora to fame both owing to the development efforts made in the LT5 project). Like a blindfolded prisoner that had just been shot while sitting on the edge of a grave pit, the final push into the pit for the LT5, was the LT4...(Well, maybe so - at least for the more naive Corvette buying public, sauteed in the concoction cooked up by the collective efforts of GM marketing in cahoots with GM Powertrain to dispel interest by the hapless public in the King).

But, the trouble with facts are they are stubborn things! The fact is, it took 11 years from the LT5's intro for GM Powertrain to match the (albeit only peak) hp of the LT5 had in '95; a fact not lost on those watching Corvette closely. The ZR-1 earned its place among the great Corvette icons, 'jewels in the crown of Corvettes' including the first Vette - the 53, the 283 cid fuelie '57, the 327 fuelie SWC of 63, the 70-71 ZR1s, the L88s, the Duntov racer, the 96 GS, the C5Z06, C6Z06, and the C6 ZR1. The C4 ZR-1 also 'put its flag in the ground, signifying it as an important icon in Corvette history, and continues to carry a vibrant support group to this day

For those who treasure the C4 ZR-1's performance distinctions, and are willing to pay for them, much has been accomplished in the years following its introduction to at least keep its performance relevant and competitive with the newer Vettes, even if road course handling is a "bridge too far". And, the DOHC architecture of the LT5 provides some significant advantages of its own, and accepts modifications extremely well in terms of power adders. The fact that the LT5 specifically was a very limited production motor adds considerable cost to such mods, compared to LS costs (i.e., a $5500 price tag for a stroker crank, and $2500 for regrind cams (to say nothing of billet cams!). But, for some enthusiasts, it is a cost worth enduring.

All that said, when you consider the fact that most Corvette drivers never run their cars on any track, much of the performance afforded by the newer cars is rather moot, in reality. So, depending on how much one can do his own work, the ol LT5 will still put up some incredible performance numbers at a reasonable cost, all the while providing that one thing that GM hasn't been able to diminish and that is the ZR-1's distinctive history and very respectable performance and unique (to Corvette) power delivery.

Long Live the King!

pushrod-v8

That power is available for stock 350 motors.

JrRifleCoach

Here ya go..

bb62

Lloyd, part of my answer was directed to the person who believes the old SBC architecture can still compete with today's technology.

But as to your comment. Consider that the high mileage L98s demonstrate "durability" which in automotive terms is very different that "reliability". They are measured differently. Durability was given a big boost by electronic fuel injection and computer control - something the old carb "powered" cars didn't have.

Consider too that wear on an engine is driven by many factors, not all by machining process - many wear factors are studied by NVH analysis. OHV engines, because of their much higher valve lifts and higher resultant stress on a key rotating mass within the block (the camshaft), actually causes higher torsional bending forces within the block - something an NVH engineer would call a resonant frequency. This resonant frequency, which results from the bending of the block under load, also impacts the crankshaft and the bearing surfaces. Unfortunately, the OHV design itself, causes the very wear on the bearing surfaces that an OHC design doesn't have (as much) to worry about. It's part of the reason why the LT5 is so smooth even though as a 90 degree engine, it is not a perfectly balanced engine (like an I6 or V12 would be).

The newer LS design counters some of these forces by better materials, roller tappets, and, lighter rotating masses (I believe that Chevy copied the Ford process of pressed on cam lobs). A lot if this type of technology was thrown at the LS to make it the successful product it is today. But in a nod to Paul's write-up, it would be interesting to see where the LT5 architecture would be if these same LS technologies were used in the LT5.

Nice write-up Paul!


I agree entirely. I bought my 95 ZR-1 back in 2008 (at a time when ZR-1s - especially 95s - were a bit more expensive) and could have purchased either a C5 Z06 or C6 Z06, but chose the ZR-1 for the legacy of the LT5 motor and what it represents to me. It IS a very personal thing. I respect and admire what the Corvette team has done with the following generations, but still felt like the ZR-1 was the stablemate I wanted to complement my 67 435HP coupe.

pushrod-v8

Not true. You can have the factory cams redone or buy aftermarket. Either are both prerty expensive for a extra ~30 plus whp.

B17Crew

Mr. Workman, your post was a quality read and I enjoyed the information.

B17Crew

Tom400CFI

Negative. That power is available for modified, 350 motors. Not stock, 350 motors. STOCK 350 motors made 375 or 405 hp. JrRiflecoach is right that the cost is kooky. Only way to make those mods worth it, IMO is port the whole top end yourself.

pushrod-v8

Stock block, crank, pistons, and stock heads and cams.

Of course cams and heads modified.

Next time I will be much clearer!

mike100

I can side with either end of this argument, but it is hard to convince people of the intangible properties a really premium engine has if they have never driven one of these cars.
I think about cashing out all the time for a Z06 or something, but I would really miss my 91. It is just too cool to drive around in.

MavsAK

But for the cost involved, is it really worth it?
Hell you could argue that in general for modding an LT-5, compared to any other platform, unless you do all the port work yourself.

It's not a bad engine, I don't want anyone to get me wrong there. Like I said, I want one, either a ZR-1, or just the engine as a display piece, because of the milestone it represents.
But when you make a BBC look cheap to mod by comparison, for a guy that mods his cars it's a steep proposition.

Paul Workman

Just for the record...

Excluding tooling purchased for the job. my DIY "500" package came in at $3570, excluding tooling. "All in, it was $5700 including tooling and a replacement head (long story). Best money I ever spent!

Far as costs to beef up the C4 for big power, a dual disc clutch ≈ $1200 from RAM, and 31-spline spindles from Mark Williams Enterprises is ALL that has been needed for the 427 and 441 LT5s that AES built and Pete/Bob assembled to date. (Both items were developed for and installed/tested before being presented by semi-pro drag racer Bob Gillig at C4 gatherings in Bowling green.)