GreasyB

That isnt too bad of a price. Only thing I am worried about is there was a paper that came with the cylinder heads saying they had moved the valve location a bit in the casting to make up for the bigger valves. I'll try and scan it and post it soon. But either way basicly it said they moved the intake valve a bit and to not be concerned if the rocker seems a bit ofset on the intake side.

Steve in Seattle

I guess it depends on how much lift you plan on seeing, and the red line your shooting for.

Shaft rockers seem overkill for any engine with a LT1 computer... Do you plan on breaking 7000 rpms? what displacement/cam is this engine running? I've talked to some builders with serious builds that still used stud rockers (7/16" ARP studs, and SS Comp rockers, and Ti values seem to be the norm in those).

I love the idea of shaft rockers, but even at $800 it seems a bit excessive (compared to say bee hive springs, tool steel retainers, and maybe a lighter valve). Cost no object its clearly a nice thing to have, but not really at the top of the priority list.

1989TransAm

Using the mid-lift theory I had to install longer studs in order to get enough thread to tighten things down. Like you found I had to use longer pushrods to get the minimum sweep.

James Montigny

7000-7200 should be the RPM limit since I'm on a stock ECM.
Peak power will be in around 6700-6800.

It's a 383 LT1 with ported Dart heads (211cc / 299cfm @ .600) and a custom HR 23x/24x 10xLSA cam. Lift is just over .600
Build Details -> http://www.cardomain.com/ride/2297151/6

I ordered a set of 2.100" ARP studs (old were 1.77"), they arrived today. That should solve the problem.
Shafties were too large of an investment with minimal gains.
(other than being sure about my valvetrain geometry)

GreasyB

Does anybody know if sombody has run shaft mount rockers on the lt1 dart heads yet? Also, James, what was the part # for the longer studs?

AdioSS

I haven't seen anybody mention the base circle on their camshafts. A smaller base circle would need longer pushrods than a standard base circle.

Stack up the changes in dimensions from the cam base circle, machined block, machined head, non-stock lifters, longer valves, different rockers, etc and the length of the pushrod needed to get proper geometry can change a bunch.

James Montigny

I used ARP 334-7203

They're also avaiable in various other sizes from 1.80 to 2.10"

GreasyB

Thanks. Also what valve covers are you running to fit all of that? And are you running the alternator in the stock location is more what I'm getting at.

James Montigny

Stock Alternator with Canton VCs,
Stock VCs don't clear the promags with 7.500" pushrods.

James Montigny

Quick update, the 2.10" studs are installed and solved my valve train problems.
Plenty of stud inside the rockers now and the polylocks sit good and tight.
I've had it to 7000 several times, no signs of problems.

GreasyB

Good to hear. You get any #'s on the set up yet?

James Montigny

Pushed just above 460 at the wheels @ 6000rpm though a locked 4000 stall and single 3" Hooker.
Still have to finish tuning to 7200 once I get the S60 in.

We just finished the dual 3" setup and installed a lighter balancer last
weekend, which should help but the new S60 is going to eat a little power.
Hope it gets here soon, I toasted the 10-bolt LOL

1989TransAm

That is good news.

marshall93z

Nice power!

GreasyB

Those are some awesome numbers.