Will these pushrods work?

[Bronze Barracuda]

More Information for MELLING MPR381



I need to buy new pushrods as I have lost the original ones from my 1990/91 360
I am putting a set of 1974 360 heads on it.
The block has the oil galleys for the rocker shaft.
But these push rods are drilled.
I have a few thoughts running through the old noggin.
Do roller lifters require drilled pushrods? and where does the oil go when it runs into a dead end, at the rocker shaft?
Also will there be a drop in oil pressure if I use drilled pushrods?
I am thinking these are stupid questions as the block does have oil galleys for the rocker shafts anyway. With the amount of $$$ I have sunk into this I guess I'm looking for a little reassurance.

PS in regards to date stamps on the block mine is 3 10 90 Is that March 10 1990 or 10th of October 1990 in which case it'd most likely be a 1991 block?

 

[Professor Fate]

Well, those are what's listed for a stock replacement '91 roller motor, so yeah they'll work- assuming you're using factory rockers.
Your motor is an LA block even though it's a roller, so it is drilled for rocker oiling. It's the Magnums that aren't drilled in later years.
Pushrods being drilled for oiling won't matter.
The only issue I see is the heads- '74s weren't designed for roller lifters, so the pushrod holes may (most likely will) cause some interference with the pushrods because they were located differently on roller motor heads to accommodate the different angles brought on by the taller roller lifters. You may need to have the holes clearanced to get the room you'll need.

 

[Bronze Barracuda]

Well, those are what's listed for a stock replacement '91 roller motor, so yeah they'll work- assuming you're using factory rockers.
Your motor is an LA block even though it's a roller, so it is drilled for rocker oiling. It's the Magnums that aren't drilled in later years.
Pushrods being drilled for oiling won't matter.
The only issue I see is the heads- '74s weren't designed for roller lifters, so the pushrod holes may (most likely will) cause some interference with the pushrods because they were located differently on roller motor heads to accommodate the different angles brought on by the taller roller lifters. You may need to have the holes clearanced to get the room you'll need.

Thanks. I've had the pushrod holes enlarged. Hopefully it'll be enough to provide clearance

 

[furrystump]

As to your question “where does the oil go when it dead ends in the rocker shaft” it doesn’t dead end. The rocker shaft has grooves cut in it that allow oil to lubricate the rockers and shafts. Also the “leaked” oil is “directed” to the tip of the rocker to cool the springs. If you are talking about the oil in the pushrod dead ending. It also weeps out between the rocker cup and pushrod.

 

[RustyRatRod]

I guess in order to know the real answer to your question, we'll need to know if your lifters oil the pushrods or not. If they are stock LA roller lifters as previously stated, I'm gonna say no. But without a picture of the pushrod seat, your question really cannot be answered accurately.

 

[Bronze Barracuda]

As to your question “where does the oil go when it dead ends in the rocker shaft” it doesn’t dead end. The rocker shaft has grooves cut in it that allow oil to lubricate the rockers and shafts. Also the “leaked” oil is “directed” to the tip of the rocker to cool the springs. If you are talking about the oil in the pushrod dead ending. It also weeps out between the rocker cup and pushrod.

Thank you, and yes I was referring to the pushrod where it dead ends to the rocker. I'm curious what the reasoning is for drilled pushrods if the motor still has oil galleys for rocker shaft oiling. That's why I thought there may be an oil pressure drop, with 16 new pathways for oil to leak . I guess the underside of the rockers will be well oiled.

 

[Bronze Barracuda]

I guess in order to know the real answer to your question, we'll need to know if your lifters oil the pushrods or not. If they are stock LA roller lifters as previously stated, I'm gonna say no. But without a picture of the pushrod seat, your question really cannot be answered accurately.

Ok that makes sense. I'll have a look see.

 

[furrystump]

Three places you need oil. Pushrod tip, rocker fulcrum and valve tip. With pushrod only oiling, the oil goes through the pushrod and exits through a hole in the rocker cup. Collects in the rocker body and lubes the fulcrum. Also gets thrown towards the valve spring area by rocker action. With shaft oiling a stock rocker it’s the same but you get occasional splash oil to the pushrod tip. Not the greatest plan. Picture pushrod through the rocker cup.

 

[mopowers]

Roller lifter LA motors used drilled pushrods from the factory. I have a great set of used ones you can have if you'd like.

 

[Bronze Barracuda]

Roller lifter LA motors used drilled pushrods from the factory. I have a great set of used ones you can have if you'd like.

Thanks I appreciate it. I should be getting the heads back from the machine shop this week. I'll let you know as I may need shorter pushrods, as there has been a lot of changes from the factory setup. Like older style (1974) heads, the rocker spring seats have been machined (I believe .020) and both the heads and block have been resurfaced. With all this I may need a different length pushrod than the factory length.
I'll PM you if I could use them.