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Mail From: Lee=Atkinson%Port=Perf%Port=(email redacted)

>From: KEN CANIGLIA

>This is being sent to respond to Jonathan Derrenbacker request for 289 hop-up
>ideas...
(snip)
>.. I wouldn't go with 351 heads. Its hard to find the right ones and your
>going to have to rebuild them anyway. The 289 heads tended to have small
>combustion chambers and compression tends to be a problem when you switch to
>either 302 or 351 heads. With flat top pistons the small chamber heads make
> a little over 10 to 1 compression. If your rebuilding your own heads and
> have to replace any valves go for the larger ones. Also remember the
> exhaust side ports to be opened up. A hand grinder and lots of
>time/patience is all that's needed.
(snip)
>Ken Caniglia

I know '69-70 351 W heads are always "supposed" to be the "right"
small chamber head, but in fact I believe that they are -all- 59-61cc
chambers all the way up to '76. These 351 heads give the advantage of 1/8"
bigger port size besides bigger valves. If you find a set of good heads, you
get the whole set of valves, etc. If you have to cut all new pockets or
upgrade, putting valves as big as Chevy 2.02/1.60 is common in those heads.
But then, with everything you need to use those valves, you're not "budget"
anymore...
As far as the drop in compression ratio, if the difference of 5cc only
drops you from just over 10 to just over 9, is that a problem or an
advantage ? All that I've seen about compression ratio would indicate that a
point drop in CR is only going to cost you about 1% or 2% power....and the
compression ratio should only be maintained if you are using a really high
druation cam. The "GT-40" heads Ford sells now are listed at 65cc but
apparently are otherwise the old 351W head.

As far as carburetion...the Hi-pos (and I think the Shelbys) came with
all of 450 CFM at the carb. Don't do anything over 600 unless you are going
to turn 8000 rpm.
Lastly, I really wonder if screw-in studs, guide plates and non-rail
rockers are just another place to throw money, unless of course you are
using really stiff valve rates or a mechanical cam. Do the new 5.0s use
these ?

It seems to me like finding a pair of 351W heads (which cost $35 each
around here) makes a hell of an economical start for a budget hop up.

Lee A, my $0.02...