327 only from factory.
double hump heads
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Yes. The 186 castings were used on 1969- 1970 350's and had accessory holes. The 414 and 291 were also double humps with accessory holes (1969 or newer). These need work to flow well but can be ported extensivly and can be a very good head depending on how much money and time you want to spend. If numbers matching don't matter buy a set of good aluminum heads with modern chamber design.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
My info shows 3927186 - 3927187 was used on 1969-1970 corvette.
Also 3973414 used on 1970 LT1 370 HP.
Also 3991492 used on LT1. I think this was an over the counter or crate engine head.
All are double humps with accessory holes. I am sure the 186 was factory installed for Corvette and fairly sure the 414 was as well but I could be mistaken. My Corvette by the numbers book is at the shop.
Also 3973414 used on 1970 LT1 370 HP.
Also 3991492 used on LT1. I think this was an over the counter or crate engine head.
All are double humps with accessory holes. I am sure the 186 was factory installed for Corvette and fairly sure the 414 was as well but I could be mistaken. My Corvette by the numbers book is at the shop.
Team Owner
Joined: Jun 2000
Posts: 38,923
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From: Southbound
Cruise-In II Veteran
My bad. Nomenclature. I've been around long enough to actually remember 327 double hump heads. The 69 and later castings are different. The group I ran with did not call the 69 and later heads "double hump." We always used the casting number. 186, 291, etc. To us, "double hump" was always 68 and earlier.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Yes, I have been around long enough to remember those too. I have spent months of my life porting them by hand back in the day. That was all we had back then to make power and I was the grunt at the only performance machine shop within a hundred miles or more. I ruined more than a few dozen of these for use by the numbers matching guys.
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