bartaxr8

I don't dissagree with any of you, but I was just wondering what is so bad about these cylinder heads? Is it the ports, valve sizes, combustion chamber sizes? Thanks in advance for any info.

EB 5.6

Long port with small minimum cross sectional area

Chamber lends itself to detonation easily.

barry_v

the 1.78" intake valve doesnt help either. its actually the same size as stock 289 heads.

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1992 DC LTD 5.0
Duel exhaust, Genie extractors, Ported E7 heads, ported lower HO inlet, 70mm maf, Underdrive Pullies

xpc66

Not necessarily. 289 standard were 1.67/1.45. Hp289 were 1.78/1.45. Remember that the last of the 289's had 302 2V heads fitted because of botched management.

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Go the Brisbane Lions