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Sep 5, 2003 | 01:32 PM

Goodold71

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From: "The Backroads"

BB Head question

I have a 429 out of a 72' LTD. I am making it a 460. I was told the heads on this engine are prone to detonation at high rpms and should be swapped out for another year. I want to install roler rockers.What year of heads should I buy at the wrecking yard? And are 429 and 460 heads the same? I was told all I have to do is change the crank and rods to make my 429 a 460 is this true or do I need to put 460 heads on also? Thanks

Sep 5, 2003 | 01:59 PM

georgedavila

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BB Head question

You were given the right information, the only difference between the 429/460 is the stroke and the '72 heads are detonation prone at higher compression ratios. All 429/460 '68-86 heads are interchangeble.

Early ('68-71, C8, C9 and DO) regular production heads use a rail rocker arm system and have smaller combustion chambers (75-78cc). '72 up use a pedestal rocker arm system and have combustion chambers from 89cc to 98cc.

Sep 5, 2003 | 05:59 PM

Goodold71

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BB Head question

Thanks. So which would be cheaper to add roller rockers to and which will run better on 87 octane pump gas?

Sep 5, 2003 | 06:47 PM

georgedavila

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If you're going to run 87-octane, that means low compression and the later heads would be your best choice. With 87-octane it doesn't sound like a high rpm performance engine, so why waste the money on roller rockers?

Sep 6, 2003 | 09:35 AM

Goodold71

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To free up hp.So Dove heads will not run with todays gas?

Sep 6, 2003 | 10:34 AM

georgedavila

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Its doubtful that you'll gain any hp with just roller rocker arms and you'll have to add guideplates and hardened push rods to use them. Figure on $210 for the roller rockers, $30 for the guideplates, $50 to mill the pedestals down on DOVE heads to compensate for the guideplates and $110-140 for hardened pushrods. Roller rockers are normally used on engines that will be turning in excess of 6000 rpm as rail rockers aren't designed for much over 5000rpm, high 5s with guideplates and hardened pushrods. CJ/SCJ engines were designed for 5800rpm using 5/16" hardened pushrods and guideplates and always bent pushrods. That's why most roller rockers require 3/8" pushrods.

DOVE heads can be used with 87-octane, just use pistons that will get your compression ratio down to about 9.5:1, preferably less. If you're putting DOVE heads on a '72 up block with stock pistons, you'll end up with about 9.3:1.