ZL-1 & L-88 head design clarification
 

Hello,

I am doing some research into building an L-88 engine for
a project. I know the L-88 in 1967 used a different head,
but I'm not sure what it was. I'm trying to determine
which heads were used in the 3 year L-88 program, which
heads were used in the ZL-1 program, and how the cross-over
between the L-88 & ZL-1 programs worked ( if at all ).

I've been told the L-88 ( 68 through mid-1969 ) may have
used the '842 closed chambered heads. Sometime in mid-
1969, the ZL-1 came into being as did the '074 open
chambered heads. Is this where the cross-over happened?

Here are some questions:

1) Were all L-88's equipped with aluminum heads?
2) The ZL-1 was open chambered, but when did the L-88 go
that same direction? Was it also mid-1969?
3) Where does the whole LS-6 program fit into all of this?
4) Does anyone have an example of a closed chambered L-88
piston, open chambered L-88 piston, ZL-1 piston that they
can post pictures of?

I thought this would have been easy to figure-out. https://www.yenko.net/ubbthreads/imag...emlins/eek.gif

Steve

Re: ZL-1 & L-88 head design clarification
 

The L-88's all were aluminum heads from the factory. The 69 switch over from the 842 closed chamber design to the 074 open chamber design was around serial # 21,000 (if my memory serves me well) But as a side not the L-89's did not change to the 074 they were all 842. Hope this helps, Rich.

Re: ZL-1 & L-88 head design clarification
 

Also the L-S6 for the Corvette was the 454 version of the L-89 but they had aluminum open chamber design heads.

Re: ZL-1 & L-88 head design clarification
 

The L88 head was also made in steel as a parts replacement item.
If you went to the parts counter at a Chevy dealer and ordered an L88 long block, it would come with the steel heads. I have a CE stamped 512 block, and on the inside of the head is stamped L88.
The casting # for these heads is not listed in all of the Chevy parts books, like Colvin's.

Re: ZL-1 & L-88 head design clarification
 

[ QUOTE ]
The L-88's all were aluminum heads from the factory. The 69 switch over from the 842 closed chamber design to the 074 open chamber design was around serial # 21,000 (if my memory serves me well) But as a side note the L-89's did not change to the 074 they were all 842. Hope this helps, Rich.

[/ QUOTE ]

Rich,

The L/89's refers to 67-69 - correct? Would an L/89 454 in
1970 have the '842 heads? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Steve

Re: ZL-1 & L-88 head design clarification
 

[ QUOTE ]
The L88 head was also made in steel as a parts replacement item.
If you went to the parts counter at a Chevy dealer and ordered an L88 long block, it would come with the steel heads. I have a CE stamped 512 block, and on the inside of the head is stamped L88.
The casting # for these heads is not listed in all of the Chevy parts books, like Colvin's.

[/ QUOTE ]

Andy,

What was the casting number for the steel L-88 heads? I've
never heard this before. Love to know more. Also, what
made them different from any other rectangular port big
block head of that same production period?

Steve

Re: ZL-1 & L-88 head design clarification
 

The L-89 in '70 was only for the 396. The L-S7 that never made production would have had the open chamber aluminum heads. (Which over the counter could have steel heads also.) The L-S7 was to replace the L-88.
P.S. The L-89 in 70 was closed chamber.

Re: ZL-1 & L-88 head design clarification
 

Steve, I wish I had taken photos of the casting numbers when the covers were off. The "HI PERF" is there, and the dates are March and April of '69.
They also have the "half moon" casting mark, indicating a closed chamber, square port application.
Difference between them is the amount of grin on your face at WOT. https://www.yenko.net/ubbthreads/imag...ns/naughty.gif

Re: ZL-1 & L-88 head design clarification
 

Here is the casting mark.

Re: ZL-1 & L-88 head design clarification
 

They are not just 840 heads? I would think they would be since 842 and 840 are vitually the same save the material.


Jason