915 Heads

Buddy of mine asked me to ask those in the know about 915 heads. He has a pair that has angle peanut plugs and large ports. Anybody in the know have any information I can share with him?

I have a pair of OE 915 BB iron heads. straight plugs. 2.08/1.74 std valves (iirc). I could measure the port openings if requested but yours ain't those. EDIT my exhaust valves might be 1.60" MORE EDIT Ma never made an angled SB/BB head (there is a SB 915 head).

I'll ask him again on the angle plugs. These are big block heads. Huge ports, large intake and exhaust and closed chamber.

I wrote myself a note to take a pic of mine tomorrow.

They only made big block 915 heads in 67. They didn't start making peanut plug heads until the mid 70's. I have a set of peanut plug big block heads and they are 452's.

The 915 heads with angled plugs are SB heads for 340/360
They had 1.88 or 2.02 intakes, 1.60 exhaust
Also used on 340 six pack with 2.02 and off set drilled push rod holes
I don't know of any with a peanut plug

Are they angled the same direction or the outter plugs angled towards each other?

Mopar DID make angle plug big block heads. They were used on their dump truck engines. I've got a set off a 1976 D600 361 with angle plugs and they're closed chambered. Not sure of the casting numbers but I can dig them out and check.

I remember hearing something about Joe Jill at Speedwin Automotive in NY was slant plugging bb heads year ago.

Pic of chambers. Casting number 2899943.

Oh OK so Ma DID make an angled plug (BB) head. Dart4forte we need more info/pics of what you have.

I'll try and get a picture

I'd say it's a fairly safe bet that the factory didnt produce any BB heads with casting number 2780915 that came with angled plugs.

Impossible? No.
Just not likely.

If they indeed have angled plugs, and are that casting number, more likely they have been modified than being something made that way at the factory.

If they are the truck heads, they sure aren't anything you'd want to use from a performance standpoint. They work fine for what they were designed for, a low rpm grunt motor.

not good pics. BB iron OE unmodified 915's closed chambers/straight plugs.

At one time, someone offered a kit to convert straight plug BB heads to angle. Plug the OEM hole and drill/tap a new one.
I saw Sheldon Gecker's "King Kong" in the pits at the Gatornatonals, back when Max Wedge heads were the best thing available. He had a set of Maxies that had been converted to angle plugs.

They were industrial heads & used a longer pushrod.

Different heads, intake & exhaust manifolds, water pump, cam and cam drive.

BB 915 heads look like a 906 from the outside, they have the same ports as a 906, and the same combustion chambers as a 516.

Good info.

The bb 915 head has the same intake port as the 906 head, but the exhaust port is unique to the 915. It looks very similar, but the short turn/floor is a little lower on the 915. It's a subtle difference.

I haven't had a 915 and 516 next to each other in a very long time, but the way I remember it is there are some subtle changes in the chambers between the two(but I wouldn't swear to that).

I meant to say the ports sizes at the gasket surfaces are the same on 915 and 906.

30+ years ago they were desirable and found on the 1967 big block motors...but now unless they have been in time capsule somewhere and are absolutely perfect in every respect needing no machine work there are better alternatives and they come in aluminum.

Combustion chamber volume on a 915 is approx 79-80 cc with no milling and no sunk valves. 516 heads are 84-85ccs.

Non-relevant fact: Back in the early '70s there were kits you could buy to convert smallblock chevy heads from straight plug to angle plug. It involved inserting a cast iron plug into the straight plug hole and then drilling a new hole at an angle. I cant remember if it had jigs or instructions for a Bridgeport.

Relevant fact: Most 915 heads came with smaller exhaust valves. Only the HP engine heads were supposed to get the larger exhaust valves. Some of the HP heads had the letters "HP" stamped on the end of the head.

Possibly relevant fact: To the best of my knowledge the first B/RB heads to use the smaller "peanut" plug were certain of the 213 "motorhome" heads that were used on motorhome engines and had extra cooling around the plug. I do not believe that these plugs were angled. They were called peanut because they used a 5/8" socket and tapered seat and the plug body wasn't much bigger than a peanut.

There were also 213 heads that had no extra cooling and used the regular plugs. I have a pair from a 2-barrel Newport.

Chrysler wasn't building collector vehicles, they were trying to stay afloat by shipping product. The phrase "never say never" applies. That's what makes this wing of the car hobby so much fun.

R.

If Ma ran out of a certain part, they would use whatever was left on the shelf. Seen it more than once.