[Formulas]

Searched archive's didn't find much info.

I have a new set of 11/32 RAIV pushrods that I bought 100 years ago at a HO Racing garage sale

What are the limits on these critters I know extra diameter over 5/16 is a good thing but at what spring rate / RPMs does the welded on ball split open the tube or the pushrod bends / fail at?

Anyone know wall thickness or material on these?

Were there very many failures in the OEM application's?

Thanks

[Skip Fix]

Are they the ones with a "Ball" welded on the end?
If so I bent one turning the motor over my hand when the rocker got in a slight bind on mock up.

[PAUL K]

Good pushrods. I wouldn't be afraid to use them with a mild solid roller.... About a hundred years ago they were a top shelf pushrod for us.

[taff2]

I used them for 3 years without any issues on a 7000rpm 400, with Comp 995 springs on a solid flat tappet cam, so 140 on the seat and 320 open spring pressures.

[steve25]

The factory felt very sure of them to handle the 320 psi of open pressure that the springs used with the RA4 heads had at .519" net lift with a 6000 max rpm limit assuming the HO racing push Rods have the same level of quality.

Just keep in mind that with a 2.11" Intake valve your going to need at least 310 psi one the seat to run clean to 6000 rpm, especially if you running a more aggressive lobe, so if you want to turn more rpm, or your Intake valve is longer / heavery then the factory 5.200" valve lenght then you will need greater seat pressure and you will then be leaning on those push Rods a good bit more .

[PAUL K]

Originally Posted by steve25

The factory felt very sure of them to handle the 320 psi of open pressure that the springs used with the RA4 heads had at .519" net lift with a 6000 max rpm limit assuming the HO racing push Rods have the same level of quality.

Just keep in mind that with a 2.11" Intake valve your going to need at least 310 psi one the seat to run clean to 6000 rpm, especially if you running a more aggressive lobe, so if you want to turn more rpm, or your Intake valve is longer / heavery then the factory 5.200" valve lenght then you will need greater seat pressure and you will then be leaning on those push Rods a good bit more .

I would NEVER use 310 lbs. of seat pressure with these pushrods..... That is at least 3/8 pushrod thick wall material or better!

[slowbird]

Originally Posted by steve25

The factory felt very sure of them to handle the 320 psi of open pressure that the springs used with the RA4 heads had at .519" net lift with a 6000 max rpm limit assuming the HO racing push Rods have the same level of quality.

Just keep in mind that with a 2.11" Intake valve your going to need at least 310 psi one the seat to run clean to 6000 rpm, especially if you running a more aggressive lobe, so if you want to turn more rpm, or your Intake valve is longer / heavery then the factory 5.200" valve lenght then you will need greater seat pressure and you will then be leaning on those push Rods a good bit more .

I have to assume the 310lbs on the seat is a mix up? Assume you meant open psi? If not that's a crazy amount of spring for just 6000rpm