Cylinder Head Differences

[R5335]

Question regarding heads for Avanti's or any Studebaker. I've reviewed the info on Head castings from Bob Johnstone's website and what I gather is the key difference in head castings for R1 (1557570) vs an R2 (1557582) vs lets say Golden Hawk (535976) or (1555294) appear to be the combustion chamber volume. Somewhere in the review was the comment that valve sizes were all the same regardless of head casting, with Intakes at 1" 17/32 and Exhaust 1" 21/32. My question is this. Is there any difference in intake & exhaust runner sizes/volumes? Are they all the same? Is it then true the only difference is combustion chamber volume? Are there any differences other than combustion chamber volume? 

[mfg]

8 minutes ago, R5335 said:

Question regarding heads for Avanti's or any Studebaker. I've reviewed the info on Head castings from Bob Johnstone's website and what I gather is the key difference in head castings for R1 (1557570) vs an R2 (1557582) vs lets say Golden Hawk (535976) or (1555294) appear to be the combustion chamber volume. Somewhere in the review was the comment that valve sizes were all the same regardless of head casting, with Intakes at 1" 17/32 and Exhaust 1" 21/32. My question is this. Is there any difference in intake & exhaust runner sizes/volumes? Are they all the same? Is it then true the only difference is combustion chamber volume? Are there any differences other than combustion chamber volume? 

The only difference between those heads is indeed combustion chamber volume.

[John C]

Hello all,

      FYI I checked my 1557570 heads that are fresh from the machine shop and they are 58 cc's. These heads have been milled .004" to clean them up.

                                                                                                                                                                                                    John C.

[Dwight FitzSimons]

2 hours ago, R5335 said:

Question regarding heads for Avanti's or any Studebaker. I've reviewed the info on Head castings from Bob Johnstone's website and what I gather is the key difference in head castings for R1 (1557570) vs an R2 (1557582) vs lets say Golden Hawk (535976) or (1555294) appear to be the combustion chamber volume. Somewhere in the review was the comment that valve sizes were all the same regardless of head casting, with Intakes at 1" 17/32 and Exhaust 1" 21/32. My question is this. Is there any difference in intake & exhaust runner sizes/volumes? Are they all the same? Is it then true the only difference is combustion chamber volume? Are there any differences other than combustion chamber volume? 

The intake valves are larger than the exhaust valves. (You have them reversed.)

--Dwight

[R5335]

Once again, thank you for those quick responses. Glad to clear that up. 

[64studeavanti]

IIRC, when I c.c.'d a pair of 1557570 heads  58 c.c.'s seem correct. I am not sure where the 54 c.c. figure comes from.

[Geoff]

If we add a sprinkle of the Granatelli's work to the mix, I have a photo showing 70.4 (even bank) stamped on an early R2 --> R3 development car. The odd bank was stamped 70.6 (but I didn't photograph that one). That would be a drop in CR (9.7 & 9.676 to 1 respectively). This done in order to increase boost of course.

Factory 289 (3 9/16" bore & 3 5/8" stroke) cylinder swept volumes:
36.1333009 cubic inches
592.1187 cubic centimeters

A 58 cc combustion chamber equates 10.21 : 1