Ignition Shielding diff 65 vs 67 left horizontals

[Jim V.]

What exactly is the difference between the left side horizontal ignition shielding pieces (rounded stainless) between 63/65 and 66-67? All of the repro stuff delineates between the two.
Some photos would help!...

Thanks

[Wayne M.]

IMO, here's the difference

This is a set of LH '66-67s. I've stuck paper in the cutout area to represent the extra metal present in the '63-65 version.

I bought these off eBay and after I examined Noland's Vol 2, pages 172-3 and page 371, concluded I had '66-67 rather than the '63-65s that I needed. The only essential difference I can see in these GM engineering drawings is the cut-out area around the exhaust manifold collector; dimension 2.16" on the '66-7s versus 2.42" on the '63-5s, for both the front LH and the rear.

[Jim V.]

Re: IMO, here's the difference

Thanks Wayne...very nicely presented. The 2.5 exhaust clearly needed the added space versus the later 66-67 collectors. I am a bit confused by your photo however. The shields pictured appear to have the taller cut (2.42 versus the 2.16), so wouldn't they be the 63-65 version? Your white cardboard fill-ins would represent the small 66-67 2.16 height of cut out....correct?

Thanks

[Jim V.]

and oh...

Yep...after a magnified review of the NA pg 173 & 371 I understand your position. The later 66-67 shielding had the larger notch; 2.42 vs 2.16in cut further away from the engine block. Interesting...but why if the collector was smaller on 66-67?

[Wayne M.]

Re: and oh...

Jim -- I had the same thoughts as you did. But I've done a trial installation on my '65 L76 with 2_1/2" exhaust using those shown in the photo, and, as expected, no interference was encountered. But I suppose the main question is the flip side; why do the smaller notch '63-65 LH shields not interfere with the large manifold ?