Early 69 186 heads, accessory holes?

[Joseph H.]

I am in the process of looking for the correct dated 186 heads for my early 69' 350/350. I have seen heads with and without the extra holes. I have seen some threads here for very early corvettes stating the holes should not be there. Is this true for my Sept' 68 build 350/350?

Thanks................

[Joe L.]

Re: Early 69 186 heads, accessory holes?

I am in the process of looking for the correct dated 186 heads for my early 69' 350/350. I have seen heads with and without the extra holes. I have seen some threads here for very early corvettes stating the holes should not be there. Is this true for my Sept' 68 build 350/350?

Thanks................

Joseph-----


I can tell you that an original L-46 built in early November, 1968 and with 3927186 heads had the accessory bolt holes drilled and tapped. Whether every earlier set of these heads had them I do not know. However, I'd say it's like this: if you find a set of heads that were cast about the same time as your block (assuming that you have the original block) or within about a month prior to the build date of your car if you don't have the original block, those heads could have been originally installed on your engine regardless of whether they have the holes, or not. So, when you find a set of correctly dated heads with dates that were the norm for engine build-to-car assembly for the period rather than the 6 month NCRS rule, then you will have a set of heads that "defines" what a correct accessory bolt hole configuration was your car.

[John H.]

Re: Early 69 186 heads, accessory holes?

Joe -

I'm not a C3 guy, but I'd think it unlikely to find 186 heads cast/dated for 1969 usage without the accessory holes drilled and tapped. That was the year all the passenger cars went to the new "long" water pump accessory drive with the alternator on the RH side and the A/C compressor on the LH side, and both the alternator and A/C compressor mounting brackets required the tapped holes in the end of the heads.

[Joe L.]

Re: Early 69 186 heads, accessory holes?

Joe -

I'm not a C3 guy, but I'd think it unlikely to find 186 heads cast/dated for 1969 usage without the accessory holes drilled and tapped. That was the year all the passenger cars went to the new "long" water pump accessory drive with the alternator on the RH side and the A/C compressor on the LH side, and both the alternator and A/C compressor mounting brackets required the tapped holes in the end of the heads.

John-----


Personally, I've never seen a set of these heads without the drilled and tapped holes. If any exist, it will be news to me.

[Patrick C.]

Re: Early 69 186 heads, accessory holes?

I have never seen 186's without holes, I have 2 sets, all 4 have holes. My friend has 2 sets as well, all have holes. Now mine are dated as follows. L-3-8, B-3-9, C-25-9, D-2-9. I don't know the dates for my buddie's. Also, all our heads came off DZ302's.