What are they, what applications are they good for and bad for.
-Tom

 

The first ones appeared on about '63 fuel-injected Vettes. Everybody has called them "fuelie" heads, among other things, ever since.

In 67 they came out with the first ones that had the accessory bolt holes in the ends. In 69 they added the "squish" or "quench" area on the spark plug side of the chamber. The 69-up ones are the only ones suitable for most street applications because without that modification, detonation is a real problem on modern pump gas.

They are all about 64cc, some as little as 62cc but you can usually use 64 safely for calculation purposes. There are several varieties of them that came on various motors, as well as some that were over-the-counter service parts. As a groupl they are by far the best flowing stock heads for the SBC. Most of them can be made to flow enormous numbers; all the romantic talk about how fast the late 60s and early 70s Z28s and Vettes that you hear, all applies to motors with those heads on them.

Basically They are good any where that you need high flow and moderate chamber volume. They give about 10¼:1 CR on a flat-top 350. Nowadays though, the expense of taking a set of junk heads and working them up: better valves, screw-in studs, guide plates, cut the spring pockets, replace the guides and cut them for positive seals, port, polish, mill, valve job, etc., all comes up to very near what a set of brand-new Edelbrocks cost. And they still don't flow as well as the aluminum ones, which are also 40 pounds a set lighter.

I'm running a set of ones I've had for about 20 years on the 400 in my 83, that had most of that work done to them before the advent of CNC casting and resulting cheap high-quality new ones.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Perfect response.

I'll just add, years ago these were performance heads. Now with so much performance aftermarket selections the only real demand for double hump heads is for people racing in classes that require stock parts. As mentioned above, by the time you spend all the money to bring these 30 year old heads up to a good performance level, it would be cheaper to just buy aftermarket heads that already have all the work done to them and are usually better right out of the box.

As you can see below I have (had) a set myself but I also did most of the work myself so they didn't cost me as much to build up. They may go an a future 400 block.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
461 Big Block installed and ready for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

[This message has been edited by Stephen 87 IROC (edited April 19, 2001).]