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#1
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A fwiw, going thru my older Comp catalog at solid roller lobes looking for 262 degrees duration and 0.575" lift. Their High Energy Street roller lobe 4221 calls for 0.020" lash with a 1.5 rocker ratio.
Valvetrain Tech: Lash Is Much More Than Just A Little Gap https://www.enginelabs.com/engine-te...-a-little-gap/ . .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Steve C.; 08-02-2019 at 01:12 PM. |
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#2
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This from a tech article. Lash Changes....
WARNING. This might seem like a small thing, but it can be a subtle alarm. Mechanical lifter engines use lash or clearance between the rocker arm and the valve and despite a common misconception, if everything is working properly warm engine lash clearance do not change. If the lash changes – something is moving. This is true for both flat and roller lifter camshafts. Generally, if the lash increases, this means something is wearing which has increased the clearance in the valvetrain. This can be a flat tappet lifter that is in the process of flattening a cam lobe or it could mean a bent pushrod or perhaps a fractured rocker arm. With roller lifters, a minor increase of 0.003 to 0.005-inch of lash could be a warning sign that the lifter’s roller bearings are failing. This is just about the only signal you’ll get that something is wrong before the bearings begin to disintegrate. When that happens, their exit is quickly followed by catastrophic engine damage as those little needle bearings use engine oil to transport them throughout the engine. If you’ve never experienced this – consider yourself lucky. Those tiny little roller bearings end up between the pistons and cylinder walls – which can cause serious cylinder wall scoring. Or, they can find their way into the oil pump and cause it to seize, which is never a good thing. .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
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#3
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It sounds like you have the comp 308R cam. The valves are set at .020 but you also have aluminum heads which from everything I’ve read is a different setting.
Hopefully someone else can shed more light on this. Butcher |
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#4
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Yes, page 71 here:
http://www.compcams.com/Technical/Ca...terCatalog.pdf Another tid bit to consider, cell phones typically don't have fantastic built-in microphones. Often leading to degradation of audio quality. With a cell phone recording my solid roller set up sounds like a thrashing machine, not as bad in person. .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
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#5
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See post 2
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65 GTO, Tiger Gold, Nostalgia Super Stock 421, 2-Carter AFB carbs, Stock Suspension, 3550lbs Full Exhaust-- 9.70's@135 66 GTO (Retired race car) 421 CID Multiple NSCA/NMCA World Champion 66 GTO 389 3x2, 4 speed, 3.90 gear, Montero Red 33K original Miles 67 GTO 2dr Post, 428, Tri Power, 3.55 Gears 80 Trans Am Black SE Y84 W72 WS6 |
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#6
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I see what you mean now mike
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#7
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Mine normally grow around .006 when at operating temp with the E-heads.
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65 GTO, Tiger Gold, Nostalgia Super Stock 421, 2-Carter AFB carbs, Stock Suspension, 3550lbs Full Exhaust-- 9.70's@135 66 GTO (Retired race car) 421 CID Multiple NSCA/NMCA World Champion 66 GTO 389 3x2, 4 speed, 3.90 gear, Montero Red 33K original Miles 67 GTO 2dr Post, 428, Tri Power, 3.55 Gears 80 Trans Am Black SE Y84 W72 WS6 |
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