Can someone explain the difference in 23 degree vs. 18 degree, vs. 15 degree etc.. I know that is has to do with the angle of the intake valve but thats about it. Please enlighten me. Also what has to be taken in consideration when converting a motor from say 23 degree to 18 degree.

Thanks

 

The valve angle refers to the angle of the valves in relation to the bore
centerline. Some of the advantages are smaller combustion chamber
volume possibilities and reduced valve shrouding by the combustion
chamber and the cylinder walls.

For the most part reduced valve angle heads will require a specific intake
manifold and headers, most likely a special valve train.

 

Thanks for posting the diagram !! Now on the "special valvetrain" what would be required there? Would shaft mounted rockers get the job done?

 

One thing I forgot to mention is the need for special pistons, the revised
valve location requires valve reliefs in a specific location.

As for valve train, offset lifters and shaft mount rockers like the JESEL kit
would get the job done. The best thing to do is check with the cylinder
head manufacturer for specific requirements.

"JESEL Rocker Kit for Small Block Chevy 15 or 18 Degree Heads. Will fit
following heads: CFE 18°, OEM Chevy 15°/18°, Dart 15°/18°, Edelbrock
Chapman 18°, Edelbrock Victor 18°, RHS/Pro Topline 14° + 23° Iron/Alum
Raised Runner. Kit has ratios of 1.6+450 INTAKE and 1.5 EXHAUST. Kit
currently costs $1287.50 (P/N KCS-10509)"

One of the unique features of a reduced valve angle head is the
compact combustion chamber design, this allows superior combustion
characteristics compared to a 23 degree chamber.

 

So if you could get a 23 degree head that flows like the heads discussed in this thread:

https://www.camaroz28.com/forums/sho...d.php?t=436366

would the only remaining advantage of going to a 18 or 15 degree lie in the combustion chamber shape/size?




Supposing you were going to convert some heads, how are these for a starting point?
http://www.jegs.com/i/GM+Performance...02615/10002/-1