DOHC heads on a BBC

69427

69427

The Artist formerly known as Turbo84
Joined
Mar 30, 2008
Messages
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Clinging to my guns and religion in KCMO.
I was re-reading an old street rod magazine and it showed this guy's street rod where he put Porsche 928 heads on a bigblock Chevy engine. As with too many magazines, the technical depth was kiddie pool deep and there was darn few details about what it took to do it. I keep thinking about the bore centerlines and the headbolt spacing issues. If 928 heads weren't so rare it would be amusing to just mock this up to see what technical issues he had to deal with in this combination.

Anyone know the bore spacing on a 928?
 
Wasn't that a 4 or 5 liter engine? That sounds like a lot of fabrication work even if the bore centers are the same.
 
Although I think it would certainly have a "cool" factor about it, I'm not sure I see a real advantage. At least not $$$=hp. I know the 928 is a small displacement motor so it's capable of more RPM than the standard BBC. I mean, unless you just want to impress with your engineering ability (nothing wrong with that), I just don't see how you get any more performance with the 928 heads than you could with a good set of Dart or Edelbrock heads. And for the expense of the investment in 928 heads plus the engineering required to fit them, I'm thinking you could supercharge or turbocharge a BBC for some serious power.
Still I'll be curious if you pursue it. Might make a neat project.
 
I think that's a joke.

The only DOHC heads on a chevy block that I ever saw where the Mosers out of the seventies and i believe only six where made (SBC).

They sure looked nice though
 
Mike, I am one cheep bastard on this stuff, and even though never owned a BBC, I very curious what you find on this....

that shit just krazy enuff to work.....

and it wooden be the first time some product info was ripped off, or shared legit.....

:flash::mobeer::mobeer::mobeer:
 
Nick Arias heads, don't think they ever got further than the prototype stage? Batten had DOHC heads for a BBC at one time too.

The SBC ones were called Dominion heads. I mistakingly passed on a new set in Germany a couple of years ago.. They were not DOHC heads though but 4 valve heads, they were pushrod operated like stock.
 
Sonny Leonard is making Hemi Heads for Chevy or Pontiac Big Inch Pro Stock Motors, Really cool stuff,, would likely take tha budget of a small country to set up a motor to run this stuff.
 
69427 said:
I was re-reading an old street rod magazine and it showed this guy's street rod where he put Porsche 928 heads on a bigblock Chevy engine. As with too many magazines, the technical depth was kiddie pool deep and there was darn few details about what it took to do it. I keep thinking about the bore centerlines and the headbolt spacing issues. If 928 heads weren't so rare it would be amusing to just mock this up to see what technical issues he had to deal with in this combination.

Anyone know the bore spacing on a 928?
Click to expand...

Think it is 88mm
 
Custom Street Rod Build - Garage Scene
Pete Aardema
From the March, 2008 issue of Street Rodder
By Eric Geisert


The quest for more speed and more power will never end for some rodders. In a strange way, it never can, because there will always be another combination of engine and driveline parts that can be put to the test. Pete aardema (are- dee-ma) knows this fact all too well, as he's been chasing the dream for more than 20 years

A self-confessed tinkerer, pete's fascination lies in four-valve heads, single- and dual-overhead cams, and aluminum blocks-all key ingredients for a lower e.t. Or record speed. And though he has a weakness for dry lakes racing (one of his 196-cid, four-banger engines has a record at 153 mph), most of what pete has to offer is for the street.

Not afraid to try something new, pete will pull from any parts bin to make what he wants work. Porsche four-valve heads on a big-block chevy? No problem. A pair of subaru heads (with twin cams) bolted to a 200-cid model a motor? Already got one. How 'bout a simple overhead cam conversion for a small-block chevy? He's made more than 50 of them. And he's finally started to adapt the ford big-block fes with one of his single overhead valve kits, too.

By accident, we discovered that the bore center on a 928 is within .030” of a BB Chevy and with help from Arias, an all aluminum 4-valve double OHC was born. The Dyno results at Westech in Mira Loma were better than expected. The engine made an astounding 550 ft. lbs. of torque at 2500 rpm.
 
BBShark said:
Custom Street Rod Build - Garage Scene
Pete Aardema
From the March, 2008 issue of Street Rodder
By Eric Geisert


The quest for more speed and more power will never end for some rodders. In a strange way, it never can, because there will always be another combination of engine and driveline parts that can be put to the test. Pete aardema (are- dee-ma) knows this fact all too well, as he's been chasing the dream for more than 20 years

A self-confessed tinkerer, pete's fascination lies in four-valve heads, single- and dual-overhead cams, and aluminum blocks-all key ingredients for a lower e.t. Or record speed. And though he has a weakness for dry lakes racing (one of his 196-cid, four-banger engines has a record at 153 mph), most of what pete has to offer is for the street.

Not afraid to try something new, pete will pull from any parts bin to make what he wants work. Porsche four-valve heads on a big-block chevy? No problem. A pair of subaru heads (with twin cams) bolted to a 200-cid model a motor? Already got one. How 'bout a simple overhead cam conversion for a small-block chevy? He's made more than 50 of them. And he's finally started to adapt the ford big-block fes with one of his single overhead valve kits, too.

By accident, we discovered that the bore center on a 928 is within .030” of a BB Chevy and with help from Arias, an all aluminum 4-valve double OHC was born. The Dyno results at Westech in Mira Loma were better than expected. The engine made an astounding 550 ft. lbs. of torque at 2500 rpm.
Click to expand...



Cute, same # my 462 Pontiac made in my '70 Lemas/GTO convertible...:drink:
 
BBShark said:
Custom Street Rod Build - Garage Scene
Pete Aardema
From the March, 2008 issue of Street Rodder
By Eric Geisert
.....................

Not afraid to try something new, pete will pull from any parts bin to make what he wants work. Porsche four-valve heads on a big-block chevy? No problem. A pair of subaru heads (with twin cams) bolted to a 200-cid model a motor? Already got one. How 'bout a simple overhead cam conversion for a small-block chevy? He's made more than 50 of them. And he's finally started to adapt the ford big-block fes with one of his single overhead valve kits, too.

By accident, we discovered that the bore center on a 928 is within .030” of a BB Chevy and with help from Arias, an all aluminum 4-valve double OHC was born. The Dyno results at Westech in Mira Loma were better than expected. The engine made an astounding 550 ft. lbs. of torque at 2500 rpm.
Click to expand...

I was reading the latest issue of Hot Rod magazine and it mentioned how he got the 928 heads on a BBC block. He ordered the aftermarket block without all the machining done (no head bolt holes) and then drilled & tapped the block to match the head bolt pattern of the Porsche heads. I guess there was also a slight offset boring of the cylinders to better position things.
 
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