Ethan's running!!!

[egon]

Uhg- The low octane rating required a low compression ratio and lead to delay the ignition of gas in the compression cylinder so there was a controled combustion process rather than a detonation.

With the hemispherical combustion chamber you can have a higher compresion ratio with a lower octane rating than with the standard wedge type the manufactures went to. The hemi is more expensive to produce because of the valve requirements.

Many of todays engines [ those with overhead valve trains ] are again tending towards the hemi configuration. It's just more efficient combustion wise but more costly to produce.

Egon

[CJDave]

Ergon, it sounds as though you have more than a casual relationship with the famous double-rocker Chryslers. Hardly anyone knows about the high scrap rate on the head castings; or the high cost of machining those big chunks of extraordinary volumetric efficiency. [img]/forums/images/icons/tongue.gif[/img] If boondox has the stock engine (315), it's the type they called the polyspherical, which was not quite the hemi, but close. Only one rocker arm assembly per bank; I THINK on those, the pushrods alternated side to side to connect to the intake and to the exhaust rocker.....it's only been thirty years.....I could be mistaken. [img]/forums/images/icons/crazy.gif[/img] [img]/forums/images/icons/crazy.gif[/img]

[egon]

I got just enough knowledge to really know nothing about anything but enough to be dangerous with everything.

Egon

[Boondox]

Dave -- Yup, it has the poly V8 with the single rocker arm and the funky scalloped valve cover. Sure is a lot quieter now that the pipes are hooked up to the manifolds! [img]/forums/images/icons/laugh.gif[/img]

I was trying to make do with a manifold that fit that engine in a car. Unfortunately, that led to a choice between some custom exhaust work or finding the manifold that actually fit. I found the truck manifold. And bummer, the location of the generator bracket was different on those two manifolds, so the bracket I had fabricated for the car version didn't work for the truck. So back to the shop and the little MIG welder to make a better version! Since the "ears" the alternator would bolt to had to stick up four inches, I used 3/8" steel with a reinforcing plate halfway up. Rock solid, and about as ugly as the rest of the truck! [img]/forums/images/icons/wink.gif[/img]

Fingers crossed, today I'll see if my measurements were accurate. [img]/forums/images/icons/crazy.gif[/img]

Pete

[fivestring]

Pete,
How 'bout some pictures of Ethan?????