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Push rods

L

l67fanatic

New member
I'm starting to build another motor for my car. I'm gonna get JE forged pistons, xp hot cam, ported supercharger, ported heads, ported lower intake manifold, ls7 hydraulic lifters, rollermaster double roller, i haven't decided if i want 1.6 or 1.7 high ratio rocker arms. But my question is what size of push rods should i use?
 


I dont know if you planned on buying a ported lim and blower but you can do it yourself for free essentially if you have a dremmel tool
 
Depends on the brand rocker arms that you use, as well as if the ported head gets plained at all. When you get all the specs together it should be some simple math to figure it out.
 
Not really a how to thread here. Moved.

Your pushrods are going to depend on things like which rockers you use (some aftermarkets have different length) and if your heads are decked much etc etc.
 
1.6 and 1.7 rollers are a waste of money.

They also come with new pushrods.

which will probably be too long seeing as your heads will probably be milled when being ported, and the LS7 lifters like shorter pushrods.

Another person on here somewhere found 6.95's worked best with an XP and LS7 lifters. YMMV
 


Need to measure lifter preload with an adjustable pushrod to get an accurate measurement. Stock size is 7.050". ls7 lifters like around .030" preload, comp oe-r lifters around .005" i've heard. (I have a set of intense lightweight 7.050" pushrods for sale if that turns out to be what you need) $55 shipped
 
I thought LS7's were supposed to be a direct swap for our motors.
There was a thread like a month ago of a cat that put in fresh lifters with stock pushrods making ticking and couldn't figure it out... could that have been his issue?

Edit: Disregard... he had used lifters and the noise went away after idling for 5 minutes. But still... we can't use stock pushrods with LS7 lifters on a XP/S1X/whatever?
 
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If you go to the dealer and ask for the part number for a 3800 lifter, it is the same part number as the LS7.

I've never heard of a difference (size wise) between the two. I will do some measuring on Satruday.
 
GTPpower said:
If you go to the dealer and ask for the part number for a 3800 lifter, it is the same part number as the LS7.

I've never heard of a difference (size wise) between the two. I will do some measuring on Satruday.
Click to expand...

Because the numbers have been superseded numerous times.

LSx guys seem to end up with .050" larger pushrods after an LS7 lifter swap.
 


Thanks for your inputs! If it helps at all, i'm gonna get higher compression. (9.9:1 and .020 bore over hopefully) so i'll port the heads, i don't think i'll get them milled just because its not highly recommended unless you have warping going on. But if i go with 1.6 rockers, what will i use. Or what have some of you guys used in the past?
 
I am going to almost promise you won't be able to use stock push rods. Local guy did Xp cam and LS7 lifters and still had to go with smaller pushrods. Now you add in milled heads and I am 99% sure yours will be way to long.
 
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