Pushrod length?

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N1ce2k1llu

N1ce2k1llu

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I have a 1971 sb 318LA. I'm upgrading with Promaxx aluminum heads, voodoo roller cam and adjustable rockers. Does anybody know pushrod length for a hydraulic roller lifter? Stock for hydraulic flat tappit rod length is around 7_5/16". I know I can measure when the cam is installed but like to get it put together quicker.
 
you have to measure...identical pieces can require slightly longer or shorter pushrods.You really need valve train geometry to be accurate.
 
yup
better get this right
i bought a ford bronco last year (i now, strike one) and it had a fresh rebuild on it...aluminum heads, roller rockers, the works
well, the works with stock pushrods

needless to say, that engine needed to come back apart because it bound up the valve train, stretched the timing chain, bend the pushrods
 
Measure using an adjustable pushrod and a solid adjustable lifter set to the same true length as your lifters. Then youll roll the engine over, actuating the valves and what you’re looking for is the maximum amount of valve lift by changing the pushrod length. Do this on all 4 corners while simultaneously checking rocker sweep pattern over the valve. Correct rocker sweep pattern first.

If you don’t, you’ll be giving up some valve lift.
 
You get maximum valve lift when the rocker is tangent to the valve at max lift
If you do this then the geometry is off about as far as it can get valve closed off the seat
you need to split the difference
set the rocker tangent to the valve at half lift
tangent to the valve is from the center of the shaft or fulcurm to the center of the tip roller or to the top of the valvestem with Iron on stock rockers
you want the NARROWEST sweep across the valve tip
you get more area under the curve this way and your rocker is not going up at a big angle with the valve closed
when you roll the motor over the rocker should tip down at tdc about as much as it tipps up on the seat
when in the middle then measure your pushrod
 
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