whats the difference between red and blue 253

[Calum]

My question is... Can you determine high or low compression by the lettering on engine number? if so can you give us examples??

[Sandaro]

My question is... Can you determine high or low compression by the lettering on engine number? if so can you give us examples??

QR prefix would be high comp. Low comp got QS prefix during the years relevant to Sandman production. Holden achieved the different compression by the shape of top of pistons.