ZL-1 Joe Lucia

[John M.]

Joe, Is the engine in the car yet? Are you driving it? What did you do about springs and stabilizers? SB, BB, other?
Curious to know the details and outcome.
John 30025

[Joe L.]

Re: ZL-1 Joe Lucia

John-----

The engine is long-since installed in the car but the project is not completed yet. Why? I have no good excuses at this point so I'll have to admit it's just due to my own laziness. It would take about 2 or 3 8 hour work days to completely finish the project and have the car running and on the road (barring unforeseen problems).

All 1969 ZL-1's were originally equipped with F-41 HD suspension. But, suppose that HD suspension was not required; what suspension would they have had then? Well, the reasons for differences in the big block suspension system versus the small block were solely because of the additional weight of the big block engine and for no other reason. The higher rate front springs were due to the extra weight, the larger diameter front stabilizer bar was due to the extra weight, and the addition of the rear stabilizer bar was due to the extra weight (by the way, keep in mind that the rear bar was NOT part of F-41, but part of the big block option).

The total engine weight of the "ZL-1" and peripherals installed in my car will be about 15 pounds LIGHTER than the small block that was originally installed there (and, which someday will return there). That being the case, if Chevrolet had built any ZL-1's with standard suspension, I figure that they would have used exactly the suspension that I have in the car now. In any event, the handling characteristics, ride height, etc of my car should be just about exactly the same with the "ZL-1" as it was with the small block. I was 100% satisfied with the suspension as it was, so I'll be right where I want to be.

Of course, I could have changed the car to HD suspension, too. I have more than enough sets of all the NOS components required to do so. However, there are 3 reasons that I did not. First-and-foremost is that I DO NOT WANT the ride quality of F-41. For me, the ride quality loss would not be worth the handling advantages. I would rarely, if ever, use the improved handling in a street driving situation, but I would suffer the ride penalty all of the time. VERY poor trade-off. Also, keep in mind that the harsher suspension would, over time, take more of a toll on the body of the car, ESPECIALLY a 38 year old fiberglass body.

Second, if I were to change the suspension system now (i.e to F-41), I would have to change it all back when I someday re-install the original engine. I'd rather avoid that. As strange as it may sound, the "germ" of my "ZL-1" idea was the ability to install a big block in the car without the need to change suspension (either to F-41 or standard big block).

Third, as I've mentioned many times before, I am in NO WAY attempting to build a ZL-1 "clone". While I am using virtually all original GM parts or reproductions thereof, I am configuring it to my own specifications. If my only option was to build a ZL-1 clone, I would never have entered into the project, at all.

[John M.]

Re: ZL-1 Joe Lucia

Thanks Joe,
All very interesting stuff, including your reason for doing it; because you could. I asked the question because we hadn't heard if you were driving it yet and also because I've been dreaming of building a street ZL-1 to install in my 67 which now has a cast iron BB. Probably would have to remove some of the BB suspension stuff. But your dreams almost there so finish her up so we can hear how it runs and how much you like a little extra BB torque.

[Roberto L.]

Re: ZL-1 Joe Lucia

Great update Joe. You say that your car will be a little lighter than an SB car. Were those few real ZL1s lighters than common SBs?

Saludos, Roberto, NCRS #30019, RMC

[Joe L.]

Re: ZL-1 Joe Lucia

Roberto-----

From a weight perspective, they should have been very close to the weight of my car with the "ZL-1". So, that means that they should have been very close to the weight of a typical small block-equipped 1969.

[Roberto L.]

Re: ZL-1 Joe Lucia

Very interesting, so the advantage of that big Al engine was more than I suspected. Similar weight distribution than an SB car, best of both worlds. I always supposed ZL1 in between the heavy iron BB and "light" SB.

Thanks!

[Mark #28455]

it's your money

Total weight savings is about 300# for about $5000 for the block alone. You can save about 75# to 100# just by using the aluminum heads on an iron block. In addition, the aluminum blocks do have a nasty glitch called thermal expansion - aluminum expands more than iron when the temp goes up. If you are going with an aluminum block, make sure to use an engine builder who commonly builds them, you have to make sure the main bearing crush is right on (more than a few engines were replaced in the camaros and the yellow ZL1 under warranty due to main bearings).

The difference in weight distribution is negligible between an L88 or L89 vs. the ZL1 (51/49 vs. 50/50) as for handling, the L88's were kicking butt in the early 70's. My L89 with F41 handles GREAT, the real limiting factor in the handling is the tires, not the suspension.

As for the "gee whiz" factor of the aluminum engine, I can't argue with that, but you could also drop in a 400 HP LS series engine with overdrive trans for less $, still have the "cool" factor, and get 28 MPG.

Just my 2 cents,
Mark

[Clem Z.]

GM published weights for bare blocks

ZL-1 110#,cast iron SBC 180#, production 502 BBC cast iron 269# i have weighted a all aluminum BBC race engine and a SBC race engine with cast iron block with aluminum heads with all the same equiptment and the SBC race engine weighted 5# MORE than the all aluminum BBC engine

[Mark #28455]

It's like the VISA commercial!

Weight savings SB vs. aluminum BB - 5#
Iron BB vs. aluminum heads BB - 75#
Fat girlfriend - 200#

Girlfriend who likes Corvette - priceless!!!!