magnum head conversion pushrods

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Golden_commando

Golden_commando

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Hi, I'm searching for pushrods for magnum style heads on la block, cam is hydraulic flat tappet, I've read that boss 302 pushrods work but I found that they have differente lenghts from 69 to 71, so I wanted to know what pushrods lenghts people are using on this kinda of combo I was looking for Comp 7492 ones, should this ones work? I know that the correct way should be measuring my engine but I can't do that...
 
They should be measured once the motor is together, or you risk having the wrong ones for the application.
Valve stem height, rocker types, head work and head gasket thicknesses vary so anyone could only guess.
 
Also make sure you are using the correct lifters for the conversion. I believe the Amc 360 lifters are the same diameter as mopar and oil up the push rod like the magnum.
 
Mopar use to have a push rod for the convertion P5007477 . It was 7.625 in length.
 
JFLN said:
Mopar use to have a push rod for the convertion P5007477 . It was 7.625 in length.
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I used those in my 360 LA with Magnum heads, they ended up working but definitely too short; the lifter preload was not what it should have been (hyd. cam and stock Mag rockers). Ran well but probably would have run better with custom-length ones which I am going to do on all my future builds from now on, too many variables involved.
 
The mp ones are measured the same way as the comp cams? comp cams are usually a little bigger from what they advertise. If I the preload is low and I mill the heads 0.03 they should be OK then?
 
To put it simply, no not really. Many other things affect required pushrod length, there's no way to know what length will be correct until the engine is assembled. Block deck height, head gasket thickness, cam base circle, to name a few... it's not much more expensive, just get a checking pushrod to measure what you need and then order a set of 16 hollow pushrods in that length.
 
MOPEkidD-3 said:
I used those in my 360 LA with Magnum heads, they ended up working but definitely too short; the lifter preload was not what it should have been (hyd. cam and stock Mag rockers). Ran well but probably would have run better with custom-length ones which I am going to do on all my future builds from now on, too many variables involved.
Click to expand...

Mine needed to be 7.09 something, so it does vary depending on motor details.
 
I measured it today, I don't have a checking pushrod but I assemble the heads and valvetrain and used a feeler gauge between the lifter and the cam until I got the required preload, I found that 7.63" is what I need. THX
 
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