Engine: R1 heads on an R2 block

[ken-renda]

Is cumbustion chamber size (54CC VS 67CC) the only difference between R 1 and R 2 heads and do dished pistons adequately compensate for this? Is there anything else to be considered in terms of valves, springs, gaskets, etc.

[PackardV8]

Yes, Yes, No.

Actually, there are two head gaskets, thick and thin, depending on whether you want an additional half-point of compression or not.

jack vines

[StudeRich]

No other differences, but you must use a 1557570 casting # Head from an Avanti or Jet Thrust Engine to get the Avanti Valve Springs, because the same heads from a Lark/Hawk Standard 259 or 289 will have the softer springs. Or of course, you could change the springs.

Standard 289 deep dish pistons will net about 8.3 to 8.5, but the new special shallow dish "Avanti" pistons will net right around 9.0 both using the thin beaded steel stock gaskets, or .5 lower with the thick "sandwich" 1955 & 1956 gaskets.

[289stude]

I though all full flow V8 truck heads are exactly the same as R2 Avanti heads?

[jlmccuan]

Heads are the same. The valvetrain is not. Studebaker commonly used mix and match parts to achieve different ends. The hottest hopup part ever for a Stude V8, R3 heads and intake, used valve springs from the 30's.

[StudeRich]

LOL! you ALMOST got that right Jim!

It was the R1 and R2 that used the early Commander Valve Springs, R3 & 4 are NEW, special, larger, way stronger, never used before springs, some with optional inner springs that the Granatelli's came up with.

[jlmccuan]

Oh, that was another "duh" moment. Thanks for fixing it.