R2 Heads!

[mfg]

'63-'64 Studebaker Avanti R2 cylinder heads are hard to obtain these days because they were used exclusively on the supercharged Studebaker Avanti engine.......True?

[studegary]

False

[mfg]

12 hours ago, studegary said:

False

Correct!....Those cylinder heads were also used on certain Stude truck models

[brad]

Sorry, but this is one where everyone that thinks truck heads are the same are dead wrong. The spark plug seats are machined deeper for J series plugs on the Avanti, and the Truck heads still use the "H" series plug reach. The casting number may be the same, but the PART number is different!

[mfg]

1 hour ago, brad said:

Sorry, but this is one where everyone that thinks truck heads are the same are dead wrong. The spark plug seats are machined deeper for J series plugs on the Avanti, and the Truck heads still use the "H" series plug reach. The casting number may be the same, but the PART number is different!

Interesting thought, however, the 1557580 truck head always has been the ideal replacement head for the R2 Avanti engine!

[64studeavanti]

Brad, have you actually measured the spark plug seats between the 2 heads? The reason I asked, is that I have several sets of 570, some of which are known to be R1, some 555 heads and some 294 heads. All have the same machining for the spark plugs.

[1963r2]

Used on export models as well.

It was widely used here in Australia and not hard to find.

[brad]

13 hours ago, 64studeavanti said:

Brad, have you actually measured the spark plug seats between the 2 heads? The reason I asked, is that I have several sets of 570, some of which are known to be R1, some 555 heads and some 294 heads. All have the same machining for the spark plugs.

It isn't apparent to the naked eye, it is the depth of the machining. You have to screw in a spark plug to check the difference. A  "J" series plug in a regular head will have about 1 1/2 turns of thread still remaining, when fully seated. Conversely ah "H" plug in the Avanti heads will have threads sticking out of the hole.

[64studeavanti]

I have actually measured the heads I have and they are all the same. Perhaps R2/truck heads are different.  Imagine the poor parts guy or dealer mechanic attempting to get the correct one.

[64studeavanti]

Did a little more research. The part number for R2 heads is the same for the low compression heads as used on trucks snd some exports. Unless someone can establish that the same part number can be different,  I suspect this is another Studebaker urban legend.  I had the same discussion a couple of years ago on the SDC forum regarding 570 heads for R1.

Some of the more experienced Studes guys insist that the spark plug seats  are different between R1 and regular engines. Seems to be the case for R2 vs low compression truck and export heads. 

So I ask the question. How can the same part number have different machining?