Chevy hemi's?

Can someone please explain to me the Chevy hemi? I have seen numerous racers online that have a "Chevy hemi". What is this? Is this what is known as a wedge head? Who are the primary manufacturers of them, are they worth it, and do they require a special type of BBC or just the standard bore spacing types?

Thanks guys,

 

The new Chevy Hemi is built by Sonny's out of Va. It is 5 inch bore spacing (I think) it looks like Boss Ford heads on a KB block GM block

 

NICK ARIAS DEVELOPED A 3 PUSHROD HEMI HEAD FOR THE TALL TRUCK BLOCK CHEVROLET, THIS WAS FURTHER REFINED TO THE ARIAS 8.3 LITRE ENGINE. MANY OF THESE ENGINES REMAIN IN COMPETITION. THEY WERE/ARE VERY POPULAR IN TRACTOR PULL AND DRAG BOAT RACING APPLICATIONS. I'M SURE THIS INFO WILL BE REFUTED BY LES, BUT HE REALLY DIDN'T INVENT IT.

 

I had the three pushrod Arias hemi-Chevy in an altered in the late 1970's and early 1980's. It had a filled cast iron block with Nick's heads and manifold. Put about 260 runs on it with no problems.

 

There are several hemi chevrolets. The benefits are wider bore spacing for thicker sleeves or larger bores. With the larger bore, you can get a larger valve (Newberry and Brad have recently went to large valve set ups like the Fontana). Not to mention BBC bottom ends. The original Arias, the Fontana, and Sonny's new pro stock engine. The Arias has already been discussed but the Fontana powerplant is the evolution of the Arias engine. It is one of the best engines out there and several are in the top running alcohol funny cars out there (i.e. Gasperelli etc.) Sonny's engine is 5.0" b.s only (correct Bob). It is based around the boss 429 head. If you can't beat the Ford - copy it. It uses a Ford intake with a chevrolet style exhaust port. It is only available in a casting.