[bxm1968]

What engine do the #15 heads go with and are they worth saving?

I found a Bonnie nearly untouched in a wrecking yard today and it started raining pretty heavy, so I only had time to peek in and see what heads it was sporting

[1-GTO]

I'm pretty sure the #15 heads were on the Full Size Pontiacs in 1970 and for automatic cars.Look on the lip of the heads for the casting dates to be sure.

[Baron Von Zeppelin]

None of the #15 heads are any good - performance/dollar wise.
If it was a 70 Bonne with 15 heads it will have a 455 underneath them.
If it was a 68 Bonne, be a 400.
Some of the guys running Turbos might could use those heads, but they buy heads for 50-75 pair because no one else wants the 110+ cc combustion chamber.

[bxm1968]

It was a 70, is the 455 usable?

[runningbwdog]

Hi,
I bought a 70 Bonne 455 with Cast #15 heads. Factory rated at 360 hp for what that is worth.
The #15s have pressed in studs, 1.96" intakes and 1.66" exhausts. There are no bolt holes on the ends for the exhaust manifolds.
I had hardened seats installed with 1.77" exhaust valves, valve stem seals, elongated the pushrod holes for 1.65:1 rockers, put in BBC screw in studs, drilled and tapped for exhaust bolts. Had them milled to give me 9.34:1 compression. Did some gasket matching on the intake side ports.
Running a XE268 cam, Q-Jet, Sun tuned Dist, and stock logs. I have plenty of low end torque and it runs well to 5500 rpm.
Mike