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Discussion Starter · #1 ·
Got a dart 434 and found this bad rocker today while setting the valves. Never seen one do this before. What may have caused it? I'm running 1.5 on exhaust and 1.6 on intake.
It's a blown drag car. Should I buy 1 rocker or get a whole set. If a whole set which ratio would be best? See included engine spec sheet.

Dart 434
Bore: 4.155
Stroke: 4.00
Compression: 8.6
Comp Cams roller cam
Intake lift .637
Exhaust lift .631
Duration @ .020 intake 300 exhaust .302
Valve timing @.050 intake open 21 BTDC close 63 ABDC
Exhaust open 71 BBDC close 13 ATDC
Installed @ 111.0 center line
Duration @ .050 intake 264 exhaust 264
Lobe lift intake .4210 exhaust .4210
Lobe separation 115.0
Brodix track 1 cnc 227cc heads with manley valves and springs
Weiand 6/71 blower .12 over drive
Twin Holley 1000 CFM HP carbs blocked power valves #94 jets all around
NGK 4554 R5671A-8 plugs


More for Less Racer
20,955 Posts
Looks like probably an imported rocker arm, and not a USA made part??

If USA I wouldn't have a problem just replacing one after taking a magnifying glass to all of them, but if offshore made I'd scrap them all.

That's a spot that isn't a common failure, maybe was a assembly error by the guy who pressed the rocker guts in during manufacture???

With the blower, I'd just go straight 1.5 ratio if you replace them all, the blown engine doesn't need "help" from a bigger rocker ratio and all it does is increase stress on the valvetrain.

Go buy a lottery ticket, you dodged a huge bullet finding it when you did......roller needles getting loose inside an engine is a nightmare disaster.
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