I have been reading some people say they are .5 inches taller in the lifter.

It also says they are the stock replacement lifter.

When I do the cam swap I am reusing non milled heads and new stock .053 head gaskets

Can I keep my new 7.4 pushrods or will the be to much pre load on the lifters?

 

I believed the .050 taller bs also and ordered 7.450 push rods, they were to tall, ordered a push rod checker and 7.400 worked perfectly on .051 head gaskets.

 

They are .050" taller, meaning you would want shorter pushrods for the same preload.

I used 7.350" pushrods for 0.075" preload, measured with a pushrod length checker, stock 706 heads and stock Felpro graphite gaskets.

Then I went down to 7.325" pushrods when I got 799 heads milled 0.022" with LS9 gaskets, same preload.

 

What is the pre load range? .6-.9?

For got to mention 1.8 yella terra rockers are installed does this affect anything compared to stock rockers when measuring preload?

 

Depends who you ask, but IMO, 0.050" - 0.100" is an acceptable range. I would go with a little more preload than less for a quieter valvetrain. Comp sells their pushrods in 0.025" increments so you can at least get into the upper half of that range. Do a search on tech too in the gen III internal engine section.

 

It depends on the motor in my opinion. We have seen some motors need a shorter push rod and some not. Its always best to use an adjustable push rod length checker and measure.

To the poster above who purchased longer push rods for a longer lifter, you should have got shorter push rods if anything. I bet it made a lot of noise if you started it.

 

hmm ii was hoping i could use my 7.400's but now i think im gonna have to buy a length checker and see... ls7 lifter,862 heads ls9 gaskets....

 

7.425" with LS9 gaskets on mine. Can't remember what I figured for preload but it was within spec.

 

running 7.425 will be going for 7.400 with new LS9 head gasket on my 408 build

 

so ya think ill be good with my the 7.4's?