Dave1980

Ok so when ordering my pushrods, after checking valvetrain geometry I was asked if the intake and exhaust measurements were the same. I did not measure on the exhaust valve, and only on the intake valve.

What is the likelihood of having different lengths for intake and exhaust? The reason I ask is I have reassembled the lifter (LS7 back to hydrolic from solid) and it was PITA. I really don't want to check unless I really have to. So to those out there that have done this who got different measurements?

Pontiac_97

it will be the same length

cehan

When I did mine, I checked two cylinders, both valves on each. They were close enough to call them all the same.

joeSS97

It depends on the lift of your cam.Are the intake and exhaust lifts different?

Stl94LT1

Different lifts on the intake and exhaust won't affect pushrod length.

truedualws6

Different lifts will affect valvetrain geometry, but this is relative to the MID-LIFT approach. LT1 heads with longer valves and rocker studs have the geometry so far off that pushrod length would not matter anyway.

Dave1980

Not to change the subject, but are you saying that LT1 heads are impossible to achieve correct geometry with different valves and studs? (assuming your going off the mid lift approch)

Every time I read that I get confused about how to achieve what they are talking about. I reads that your roller tip does not have to be centered, but as long as you have correct geometry your ok. I wish there was a layman's way to achieve what they are talking about.

I am running the same lift on my cam on exhaust and intake, so what you said previously wouldn't apply. I am looking at spending good money on some nice manton pushrods, but would like to see how mid lift would change my current measured figure before I order.

truedualws6

My apology for the delay, it's been a busy week at work. I think the consensus regarding the mid-lift geometry for an LT1 is you need shaft (stand) mount rockers to get it close. I have all the parts to get it as close as I can with rocker studs, but it's still not "ideal". I'm going to use 7.30" pushrods.

The main things I hope to accomplish is to move the pushrods higher up in the guideplate slots (they are really close to the bottom now) and also reduce some of the valvetrain noise.

Dave1980

No it is cool. I went ahead and ordered the 7.03 pushrods from manton. I will have to check my guideplates , and make sure about the bottom being close as well. I believe the checking pushrod was very close to the guide plate also.

Any suggestions if they are touching? Should I slot the guideplates down a little?

truedualws6

I don't know if deepening the slot will affect the hardening on the edges where the pushrods will still make contact. Grinding/cutting the slot deeper will get things pretty hot which may affect the surface hardness.

You definitely do not want the pushrod touching the bottom of the guideplate slot. What I did with my GMPP guideplates is push them down towards the exhaust port side and then torqued them. Because of the play I was able to gain a little more room. THis will depend on the studs you have. Some of the ARP studs have an enlarging taper to better locate the guideplates.

Stl94LT1

I'm assuming you meant 7.30". I'll be curious to see when some of these engines running longer pushrods get a few thousand miles on them if there is any unusual valve guide wear. The 7.2" pushrods on my engine pushed the rocker lower on the valve, I can only imagine what a 7.3" is doing.

Dave1980

No I meant 7.031. I am running 0 decked block. The heads were done by Lloyd, so they were milled a little. I am also running LS7 lifters. (I think they have a different cup depth.)

Stl94LT1

OK, I'm glad you actually measured the correct length for the pushrods. Seems many just want a recommendation on what pushrod to run.

Dave1980

Naaa! No way would I do that. I went and got the pushrod checker from summit, and some 8inch digital calipers from harbor freight. (which seem to be decent for there stuff)

Here was my other thread with pics of my geometry marks on the valves.

https://www.camaroz28.com/forums/sho...d.php?t=595713