bbc 396,454?

What is the difference in the bbc oval port and square port heads?(besides the shape).

Are both style heads compatible with a 396 block?

 

Valve size.

Both were available on the 396.

 

Oval port are better street driving. Some say better performance. Rectangular is suppose to be better but is more true like in BIG drag racing stuff.

All BBC are compatable. There's Tall Block Stuff to stay away from.

 

there is also open chamber or closed chamber , referring to the combustion chamber

 

Yes, and oval and square port were made in either open or closed. Match to pistons for compression ratio. Original 396 were closed.

 

I have a set of oval port heads with Manley Valves, Springs and guides available. these are the 336781 heads, considered the best of the oval ports (along with the 049). Open chambers and 2.18/1.888 valves. PM me if you need em.
Car Craft made 589 HP and 550 Ft Lbs using a set of these Oval Ports with just a little back cut on the pocket and larger valves.

 

Are both style heads compatible with a 396 block?

Compatible... Not really. All will bolt on. But putting a set of 122 cc. open chamber oval ports on a 396 will result in a gutless, gas guzzling TURD!

You would need the early small closed chamber heads 95-97 cc. To get any power. As mentioned ^^ oval port for 396 street motor. Hard to make a powerful 396 as most of the go fast stuff is based on a 4.25" bore 427 up block.

 

Chevy managed to squeeze 425 hp out of a 396 in the '65 Corvette using the first Mark IV square-port head, casting #3856208. These heads had a 109 cc combustion chambers and 2.19/1.72 valves. Very rare and one year/application only. Pricey too, if you could find them.

 

#3856208 - 106.9 cc,2.19/1.72 valves,396/427-'65-'67,425hp 396-427. I have 4 sets.

 

Have I seen you on hoarders?

I was referring to the 'vette application. They may have been used on other engines.

 

Velocity is the main difference to be concerned about. Assuming you have the proper open/closed chamber head to match your pistons--/// the rectangle ports are a high rpm head and the ovals have smaller runners that keep velocity up at lower rpm. Much better for street rpm/torque.


Posted using the Full Custom H.A.M.B. App!

 

Don't be afraid of tall block BBC. You just gotta let me know and I will gladly take them off your hands.

Once you know how there are some big advantages.