ZLX question

[69SSZL1]

From page 150 of vintage "How to HotRod Big Block Chevys" in the Heavy duty parts list they show chevy part #3970699 as a partial engine assembly L-88 427: "430 HP L-88/ZL-X short block with 12.5:1 c.r. pistons for use with open-chamber heads, 4-bolt mains." I still dont know what ZL-X refers to.

[Schonyenko2]

I went and found my old copy of that book. Mine may have been an older edition as there was no mention of the ZL-X. But in the process of looking for it, I came across my old Nickey, and Berger catalog, and they both list it. Berger:1/2 engine assy/short blk, 0699 427/430 ZL-X 12.0 to 1 open chamber. 1/4 engine assy: fitted blk 8656 427/430 ZL-X 12.0 to 1 open chamber.
Nickey's reads: 9960 427/450 12 1/2 floating wrist pin, 4 bolt solid cam ZL-X L88 open chamber. I think they may have the part# backwards.
So it basickly is, with 026 open chamber heads, a cast iron ZL1.
It appears this was kinda the transition/ evolution to the LS7 454 crate motor.

[Geo]

I bought a ZLX in 1969. First I ordered the short block, and then I ordered the ZL1 Aluminum Open Chambered Heads which took 3 Months to get due to having to wait for them to be produced. The heads came bare so I had to get all the parts to complete plus I had them CC'ed. This engine is the same as the ZL1 except that the block is cast. ZLX is the ZL1 with a cast block. I put the engine in my 1966 Chevelle SS which I still have. The car has been stored most of the time sense 1973 due to me being stopped by the police. I used to street race and the car got to be known and that's when the police starting pulling me over just because they knew the car. I always run the engine every so often. I had the engine gone through installing all new bearings. It has maybe 1500 miles on the engine. When I ordered the engine Chevrolet called it a ZLX and that it was identical ZL1 but had a cast block.

[Geo]

Here is some info I found online about the ZLX 427

The most famous version of the 427 was undoubtedly the 1969 ZL1 engine. Developed for Can-Am racing, where it was very successful, the ZL1 had specifications nearly identical to the production L88 version of the 427, but had an all-aluminum cylinder block that weighed 100 lb less than a similar iron block. The engine was also fitted with the new open combustion chamber cylinder heads, a lightweight aluminum water pump and a specially tuned aluminum intake manifold, resulting in an engine weighing little more than a small block, but producing around 600hp in "street" tune and far more in racing tune. The 4718 dollar cost of the ZL1 option doubled the price of the 1969 Corvette, but resulted in a car with exceptional performance. Just two production Corvettes (factory) and 69 Camaros (non-factory option COPO 9560) were built with the ZL1.

Chevrolet capitalized on the versatility of the 427 design by producing a wide variety of high performance, "over the counter" engine components (marketed as "heavy duty" or "extra capacity" components to mask their intended racing application), as well as ready-to-race "replacement" engines in shipping crates. Some of the components were developed to enhance the engine's reliability during high RPM operation, possibly justifying the use of the description "heavy duty." However, most of these items were racing parts originally designed for Can-Am competition that found their way on to dealers' shelves, and were meant to boost the engine's already impressive power output. As a result of this activity, the 427 quickly became dominant in drag racing.

The version of the 427 produced from 1966 to 1969 was fitted with essentially the same cylinder heads as used with the 396, a type often referred to as the closed combustion chamber design. Starting in 1969, the highest performance models were fitted with the new open chamber cylinder head, which along with design improvements in crankshafts, connecting rods and pistons adopted from the Can-Am development program, resulted in an engine with substantially increased performance and reliability. This development culminated in a specialty version of the engine called the ZLX, which was essentially a ZL1 engine built with the L88 engine's sturdy, four bolt main bearing iron block (it has been suggested that "ZLX" was a code name for ZL1 crossover). The ZLX, available as a short block assembly or complete "replacement" engine in the crate from a few dealers, was a resounding success and became a best-seller by after market racing components standards—the closest thing to an all-out competition engine ever offered to the general public. Chevrolet gave all 427 engines except the ZL1 a torque rating of 460 ft·lbf (624 N·m).

[copo-2]

Motion Performance shows different options for the ZL-X from their 71 catalog?

My 2 cents... [img]<<GRAEMLIN_URL>>/wink.gif[/img]

I went through my old Chevy Special Equipment manual (the green page book) with a publication date of 3-9-72. I couldn't find any mention of the ZLX. There is, however a part number for the cast iron open chamber rectangular port heads, and of course, a part number for the second design L88 (when combined would obviously make the ZLX). My take on this has always been that Joel &amp; Company @ Motion coined the phrase, advertised it and the rest of the people in the biz picked up on it. In the end, I think it was pretty clever. I'd still like to get one for $1995 though...L-O-L

Wayne [img]<<GRAEMLIN_URL>>/beers.gif[/img]

[SUSQ]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hotrodsled</div><div class="ubbcode-body">My 2 cents... [img]<<GRAEMLIN_URL>>/wink.gif[/img]

I went through my old Chevy Special Equipment manual (the green page book) with a publication date of 3-9-72. I couldn't find any mention of the ZLX. There is, however a part number for the cast iron open chamber rectangular port heads, and of course, a part number for the second design L88 (when combined would obviously make the ZLX). My take on this has always been that Joel &amp; Company @ Motion coined the phrase, advertised it and the rest of the people in the biz picked up on it. In the end, I think it was pretty clever. I'd still like to get one for $1995 though...L-O-L

Wayne [img]<<GRAEMLIN_URL>>/beers.gif[/img]

</div></div>

Adjusting for inflation using the Consumer Price Index, in today's dollars you could pick one up for $10.784.65. Money well spent, indeed!

[Citation_sp]

In engineering terminology &quot;X&quot; usually means cast iron. so ZL-X could just be GM's way of stating cast iron components.

[Tracker1]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Citation_sp</div><div class="ubbcode-body">In engineering terminology &quot;X&quot; usually means cast iron. so ZL-X could just be GM's way of stating cast iron components. </div></div>

I don't believe GM/Chevrolet ever used ZL/X in their sales pieces. As mentioned, it isn't in the green sheets book. I agree it's a Motion term that was popularized by Chevy parts guys in the know.

[EZ Nova]

So WHAT intake would be considered &quot;correct: for a ZL-X motor? I see above, the 600Hp 427 is a tunnel-ram, so what would the other 4427/550Hp motor come with??? GM or aftermarket intake?