LSWHO

Didn't some big name company JUST come out with 1.7s too?

BLUETOPTA

Read the thread man.... not drilling into the heads at all here. Cash is an option to a lot of people....

1989TransAm

Is the LS1 rocker arm geometry the same as used on an LT1 or standard SBC? Just wondering how the dimensions stack up compared to a Lt1 rocker arm.

LSWHO

I did read the thread. Man. Thought you meant in the head:

OutKast

what size is the LS1 rocker bolt hole vs the size of the stock LT1 studs?

BLUETOPTA

Its a little bit smaller than the 3/8 stud stock on a LT1

MeanGreen97Z

The part that threads into the head is actually 7/16s on the LT1 already.

OutKast

well, picked up a free set of LS1 rockers yesterday. Looking at the hole size vs the studs on my heads...the rockers would have to be drilled out. Talked to a couple guys and they're telling me that the drilling is going to be difficult because the part of the rocker that needs to be drilled is hardened. Can you give any details on how you drilled them?

BLUETOPTA

To drill the rocker arm holes, you need a pretty strong drill and a strong drill bit as well.

I think I used an air drill with a hardned bit. I would use PB blaster to cool the bit between rockers

96capricemgr

You know there are cutting oils specifically meant for such things. I have never handled LS1 rockers so maybe it is obvious but how are you keeping the shavings out of the rollers??
One little shaving could cause a cheap rocker swap into an expensive bearing wipe.

BLUETOPTA

You have to be careful. I have had this setup on my car since 2004... mnay track passes and still going

moehorsepower

I agree, and surely you will be in coil bind if the spring are not changed out..

GMRL

How is the geometry affected, if at all?
Can you use stock length pushrods?
So after the holes are drilled to the correct size, you just bolt it on like you would a standard SBC rocker arm, no need for spacers or anything?

1989TransAm

How is the geometry affected, if at all?

May be the same as a small block and that is why I'm asking the question.

Are the angles from the camshaft to the rocker arm the same? How is the relationship with the studs and valves on the LS1 compare with the those of the SBC. The heads are of a different degree than the SBC. Maybe things are different enough to require a rocker arm of different geometry than the sbc. Than again maybe close enough.

Just wondering thats all.

OutKast

Picked up my set of rockers from a local shop on friday. Picked up a couple cobalt bits which are advertised to be able to handle the hardened steel. We'll see how that works out....

Seems there is a little confusion for some. You will not be drilling the head, you drill the hole in the rocker out to the LT1 rocker stud size. The LS1 does not use studs but rather a bolt which is smaller diameter than the LT1 stud.

I spoke with two local shops in my area and both feel that the pushrod size should not change. It was suggested to check that the rocker is correctly aligned with the valve tip. I'll be checking it out this week so I'll post pics of what I find.

My valve springs are good to .600 and my cam @ 1.7 will go to .589