Hi Derek,
Here's my recollection on using 351 heads on a 260,289,or 302. This was done
because the standard head, even the hi-po was a notorious poor breather,
especially on the exhaust side. The best 351 heads that are used on 289s & 302s
are those from 1969 & 1970. We use those two years because they are small
chambered and yield about 9 to 1 compression, bolt-on. Other 351s will fit, but
they will lower the compression to the extent that you will need pop-up pistons
to retain power. But if you are going to use low-quality, low octane gasoline,
then maybe you would consider this & take the resulting considerable horsepower
loss.
The numbers on the 2 years of heads are (DOOE)1970, and (C9??) for the 69s. Uh,
I'll have to look that last one up. Having a senior (Laifman) moment.
They can yield a low buck horsepower increase of 50-60 horse when used with
that cam you've got.
To run them you need the guide plates because 351 heads have slots for
pushrods, not holes and longer hardened pushrods, because the heads are thicker
& the pushrods need to slide on the guideplate. You also should use screw in
studs to retain the guideplates, alto I've seen people "pin" them. You also
need 351 head gaskets. Most people install larger valves, although you don't
have to do this. They also benefit from port-matching and grinding out the
thermactor bump.
This was an exceptionally popular "cheat" for small block Fords before the
advent of the many aftermarket heads were available, but now you can buy heads
ready-made that will yield more power, which is why I never finished them. My
Edelbrocks are on order. I think I still have a rusty ported set over a friends
house that I would gift to anyone that will use them--but he may have tossed
them--they've been there for many years (he owns the compressor I used to rough
port them.
I still do have the 16 longer hardened pushrods needed for this swap. They are
made by Ford motorsports (M-6565-C332) and are no longer listed in their
catalog.
Listers, did I forget anything except the 1969 head number?
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