Arao has been building hemi heads for SBC engines for years. They are really pent roof, 32 valve rather than true hemi http://www.araoengineering.com/chevysmb.htm
"Most of the exotic SBC head development efforts went into overhead cam conversions. But the simple fact is that the SBC is a near perfect design, and hemi heads did not offer much improvement." That's really a hard one to swallow...hemi heads aside, the SBC is hardly a near perfect design. What it is is the engine which has had millions of hours of development put into it over 50+ years. There is no other engine that even comes close. The new LS series is proof of that - it shares very little in common with the SBC and outperforms it in every way.
Cool stuff but - here's how I see it ... If you really want a Hemi style combustion chamber, and you think it is the best chamber design, there's plenty of mopar hemis to chose from. Hemis aren't cheap compared to a SBC but a built hemi engine is going to be cheaper in both initial cost and long run than a built SBC with exotic conversion head and associated parts.
First generation small blocks fitted with the latest aftermarket heads and cams are quite formidable.Yes,not as formidable as an LS, but..... I would like to see on such an SBC and a similar cubic inch Mopar hemi built for street use compared on a dyno..
But that's the point - they aren't stock anymore. The aftermarket pieces show significant changes from stock, not just minor changes. I think it's been shown that neither the wedge shape of a Chevy nor the true Hemi is going to do best, but rather the pentroof shapes of the most modern engines (and lots of older motorcycles).
The Chrys 426 HEMI was a Hemi head retrofit for the RB engine and not clean sheet of paper design, Pushrod angles are really messed up.
Don Ferguson makes a hemi head for the Chevy, cant remember if its a modified Ardun or the Lyons head. About 10 years ago the Lyons patterns were still around in SoCal and there were talks of them coming back. This is my M/T hemi head for the SBC, though its a DOHC.
Well, there's surely some monkey motion going on there, but it seems to have not held them back much. I like 'em.
Mickey Thomson made hemi heads for about one of everything at one point, I don't doubt that he made some.
I was told that Don Ferguson purchased Leo Lyons patterns etc. from Walt Austin. Production to follow????? I am also friends with the person that cabriolethiboy mentioned. His detective work and persistence paid off and he obtained a very rare piece!
I wish I could but I promised him I would not let out any of the details until he tells me it is OK. Sorry
Ron Still from Delaware ran a Top Fuel car in the late 60's with the Lyons hemi SBC heads. I believe that he has all the pieces today. Should be some pictures out there somewhere? Chase
I am pretty into 302's I have a pretty wild one myself and also am fairly knowledgeable on their history, but NEVER have I seen the factory hemi heads....really cool stuff!
Go visit the engine room at the Corvette museum in Bowling Green. They have some really cool "one-off" engines that you would kill for. I am not a chevy guy, but whoa....some of those engines are incredible. Hemi's, 3 valve, pent roofs, 4 valve etc. Wild stuff.
I've seen the Chevy/hemi deal at Walt Austin's shop...story I got while there was that Walt worked fairly long and hard to get the pattern and tooling and that it was a recent procurement for them. As far as production, I don't recall if any comment was made.
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