[Amc-list] Cylinder Head Question

["Bruce Hevner" <scramblr@xxxxxxxxxxx>]

I wouldn?t TRY to use a set of 304 heads on a 360 for performance. They
will work well for torque and MPG but the performance will suffer.
REMEMBER,,, just putting oversize valves in does not necessarily get you
better performance. I read your post and never saw THROAT SIZE (the area
under the valve seat) mentioned. There is as much or more power made in
the first ½? or so under the valve seat as the valve size itself.
 The throat area on a 304 is MUCH smaller than the 360. I don?t believe
you could ever port out the bowl/throat area on a set of 304s to be the
same as a STOCK set of 360s.  Even if you could what would you end up
with?? A set of heads that are the same as the 360.
 First you need to determine what the vehicle is used for and what RPM
will it operate? If you REALLY want to fly look at a set of Edelbrock AMC
heads. I looked at a set at the PRI show. VERY nice quality, ports and
bowl area looked great. Yeah I know they are 12-$1500 but when you add up
what youre going to spend on your stock heads, and what you?ll end up
with,, they are not such a bad deal.
304 heads on a 360 will increase the torque and response, but they?ll be
?done? by about 4500RPM. There is no way around it, you can tune for the
bottom/midrange, or the mid-upper range. But you can?t have it BOTH ways.
 If a customer asked me those questions I would recommend doing a good
competition valve job and taking maybe .020 off the 360 heads. That would
be the best all around combination.
As far as compression goes,, as a GENERAL rule you?re going to change the
compression ABOUT .1 point for every .010 you cut them. This varies with
chamber and engine size but it?s easy to figure.
 If your using a stock cam be careful increasing compression. More than
180lbs running compression will be close to spark knock territory.
If you?re going to increase compression then you need to look at the cam
timing,,,,one thing leads to another,,,,
But HEY,,, that?s just ME!
Bruce Hevner
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