Cylinder Heads Question

[67 GTX]

Hey Guys,

I have a few questions regarding cylinder heads. When going to look at a used set, how can you tell if the heads have been milled or not?

I know that the 915 heads for a 440 were 67 year only. Did a L casting indicate HP heads with 1.74 exhaust valves, and a K casting would be non-HP with 1.60 exhaust valves? are the K and L castings only located on the underside of the head?

What if the head doesn't have a HP stamping, or if it doesn't have a K or L casting?

 

[lewtot184]

the lower head bolt boss will measure very close to 1.00" in thickness on an unmilled head.

 

[wyrmrider]

most 915 heads you pull with have the small valves
which is a good thing as you can grind new seats for the larger 1.75 or 1.81 valves
still the unleaded seat problem but will work - better if you don't get it hot
I put durabond seats and knurled bronze sleeves in the guides in the ones I do

 

[PurpleBeeper]

I suggest you take a "vernier caliper" with you to measure the exhaust valves. I'm sure they are pretty cheap ta Harbor Freight. They sort of look like an adjustable "F"

 

[rick68b5]

Just look for the hp stamping on the front of the head where the alt bolts and the L and K casting doesn't mean anything I have seen both with the 1.74 exhaust valve

 

[rick68b5]

This is off a set of virgin 915 heads I have forsale

 

[67 GTX]

This is off a set of virgin 915 heads I have forsale

View attachment 559185

So then does the HP stamping indicate the bigger exhaust valve?
And I am correct in saying besides the exhaust valve, all the heads are identical correct? I could buy a smaller exhaust valve head, and enlarge it to make it identical to the larger exhaust valve head?

 

[67 GTX]

the lower head bolt boss will measure very close to 1.00" in thickness on an unmilled head.

Am I correct to assume that you are referring to the thinnest area on the bottom of the head, where it contacts the block?

 

[rick68b5]

So then does the HP stamping indicate the bigger exhaust valve?
And I am correct in saying besides the exhaust valve, all the heads are identical correct? I could buy a smaller exhaust valve head, and enlarge it to make it identical to the larger exhaust valve head?

 

[rick68b5]

You can buy standard 915 and do that yes but I don't see it being cost effective to do it

 

[khryslerkid]

Am I correct to assume that you are referring to the thinnest area on the bottom of the head, where it contacts the block?

 

[wyrmrider]

beside the exhaust valve all 915s are identical
springs were different on the HP motors but that's ancient history
915's flow like 906's
don't touch the Short side radius unless you really know what you are doing
but bowl blending and opening the bowl with a cutter when putting in the larger ex really helps
do not screw around trying to match the intake face with any gasket- that's not where any restriction is
you can use the Direct Connection templets and remember less is more and more is too much
single spring with dampner works with cams in the .500 lift area
although I used Isky 6005 set with the proper height to get the pressure I wanted- or 8005 if more pressure was needed for a solid lifter cam (more rpm usually in a stick shift car with lower gears)

 

[Garys1969RR]

I have ported, and worked on, several sets of 915 heads. The port layouts are all the same as the 906 heads. All the 906 heads have the larger 1.74 ex valves. In 1967 the 915 heads came on all 440s, but only the GTX and Dodge RT had the HP 915s with the larger ex valve. Yes, you can have the 1.60 ex valve heads opened up to the larger 1.74 ex valves. Or you can go all the way up to the 1.81 ex valves. When doing this, get the port pocket opened up some to improve flow. You can also install larger 2.14 intake valves. These heads respond well to mild porting, but it isn't cost effective unless you do it yourself. Alum heads are relatively cheap, flow well, and are much lighter.

 

[Garys1969RR]

Here are some pics of ported Stage VI intake ports.

 

[wyrmrider]

I have ported, and worked on, several sets of 915 heads. The port layouts are all the same as the 906 heads. All the 906 heads have the larger 1.74 ex valves. In 1967 the 915 heads came on all 440s, but only the GTX and Dodge RT had the HP 915s with the larger ex valve. Yes, you can have the 1.60 ex valve heads opened up to the larger 1.74 ex valves. Or you can go all the way up to the 1.81 ex valves. When doing this, get the port pocket opened up some to improve flow. You can also install larger 2.14 intake valves. These heads respond well to mild porting, but it isn't cost effective unless you do it yourself. Alum heads are relatively cheap, flow well, and are much lighter.

EXACTLY
and do not even think of installing the 1.88 Max wedge exhaust valves (The motor home valves are the best quality SIL-XB intakes and Inconel headed exhausts both with thick industrial hard chrome stems- the 2.14 1.81 valves do flow better and both flow better with some hand work
The motor home valves last longer under street or HD use (the center two ex valves run hot)
Also do not try and drill the heads around the plugs like some 452's

 

[67 GTX]

Thanks guys. Does anyone know if the 915 heads with the larger exhaust valves also had to have an HP stamping on them?

 

[wyrmrider]

I have 6 sets at the shop and can check but HP stamp was on the Blocks
anyone else remember?
the only difference was the Ex valve size

 

[67 GTX]

I have 6 sets at the shop and can check but HP stamp was on the Blocks
anyone else remember?
the only difference was the Ex valve size

Thank you. I've seen some heads that had an HP stamping on the boss where the alternator bolts too.

 

[rick68b5]

Thank you. I've seen some heads that had an HP stamping on the boss where the alternator bolts too.

The real heads are stamped on the alt boss

 

[wyrmrider]

Thanks
It's been 20 years- guess I should look at the pile and see if I have any
Hard to do anything with these heads with the AL being so resonable
I'm hoarding them for any matching number builds or just ornery nostalgia
I do have a set all ported and just need a refresh
stock size valves as they were for a motorhome