robsquikz28

iTrader: (246)

Chris, what valvetrain did you have?

Z8'S

iTrader: (6)

DRE shaftmounts/ 3/8 pushrods /comp R lifters/ 943 springs/AFR rev kit.

speed_demon24

iTrader: (6)

You might want to tell that to gm who was running their h/r stuff to 8500 in the their road race caddies.

robsquikz28

iTrader: (246)

I said that due to the fact that this thread has gone way off the tangent. ITs gone all about Thadd and him being the only PCm in the world to 7500 lol.

Wicked94Z

iTrader: (26)

Excellent combination of parts and definitely NOT your typical HR type build with that spring... LOL my solid roller setup is built around the 1243, ~.750 lift but...

I'm sure 7500 is doable with ~160 on the seat and 380-400 open if you keep the valve side mass low. I'd stay with a solid stem 5/16 valve if you don't want to spring for hollow 11/32 stuff, titanium retainer on a light beehive and you're there. Cheaper than your average SR setup for sure, but those heavy lifters are going to kill valvesprings if you want to push lobe intensity

THADD

iTrader: (12)

You can say what you want, but my car has spun over 7000. I will tell you what, once I get back to the dyno to tune my new nitrous set up I will make a little vid just for you.

robsquikz28

iTrader: (246)

I will be waiting
Im not the only 1 doubting you and I have a mallory in my car as well and I was running nitrous too. It never mattered what I set my box to as for rpm limit, the pcm still did what it wanted. I have never seen the box over ride a pcm????? Maybe im wrong and have been doing this for years and maybe my pcm was junk but idk....
Either way I want to see your car on the dyno or even track

RamAir95TA

iTrader: (2)

I don't want to see a dyno run or a track video, I'd want to see a recorded datalog (in CSV format) from the PCM showing the RPMs.

Puck

iTrader: (17)

Yea, I had no idea he was running an HR grind. I had the springs measured and when the shop told me the springs were 260# installed @ 1.870 I assumed it was an SR.

I cannot find ANY info on the PAC-1243s besides a quick mention in a speedtalk thread and an ordering page that only lists the OD. Their site does not even find them in a search(?). How long have you been running them, and have they been measured again to check fatigue?

If they can reliably handle high rpm builds with .750+ lift and are sub-$300 they would be exactly what i need to replace my 943s(which won't handle the lift of the cam me and Llyod are thinking about).

It looks like they are 240# @ 1.9, with coil bind @ 1.100, but if you have their closed #s and rate/in it would be great...

::EDIT:: Found a page with a bit more info from some random website. "PAC1243 240@1.900 625@1.200 1.100 Coil Bind". Being circle track springs, how would they hold up to street duty and repeated heat cycling?

Apologies for the slightly OT, this thread is all over the place but hopefully its info someone else may need.

robsquikz28

iTrader: (246)

PUck what springs are you looking for in particular? I might have some for ya??? send me a pm with the specs needed?

robsquikz28

iTrader: (246)

I guess ONLY 1 real man on tech has gone above 7500 rpms safely and he is a well known guy in the chicago area and On tech.

Puck

iTrader: (17)

I need something with ~1.900 install height, ~250# closed, ~650# open, and good to .750 lift.

I think the PAC-1243s would work spec wise, but they seem a bit cheap @ sub-$250 and I am worried about their reliability in a car that sees street duty.

robsquikz28

iTrader: (246)

Okay I have 1 set that is brand new and is suppose to be good to .750 lift. I bought them with a set of heads and thats what I was told. If you have access to a machine shop and install them at 1.9 ht you can check them and see if they are good. They were installed at a 1.95 ht originally. I can send you one of them complete and you can shim/ check them for pressures and all if you want??? lmk

KENS96M6

Not concerned with the cam questions as I am going solid roller, but I would llike for someone to explain how I can get my OBD2 to rev past 7000. Not being a smart ___, just need more info.

Wicked94Z

iTrader: (26)

comp 943 IS a PAC 1243 I'm not running them yet, but i'll let ya know later this year. The advantage to that spring is MASS. You can set them up at 1.89 or so and run .750 net, which lets you use a +.100 valve instead of a .200 or .250, there's a few grams savings. It's a 1.55 spring vs a common 1.625 you'd set up at 2.00" which saves you another 30+ grams of spring + retainer mass. Obviously the entire spring is not moving, but lets say ~15 grams of moving mass saved. Also you can run a cheap 731 style titanium retainer from trick titanium for 200 bucks as well.

Those 20 grams saved are the equivalent of a hollow stem valve ($$$) but you can still run a solid stem severe duty and run the same rpm. On an 8000 rpm motor, every 10 grams you can take out of the valve side is 300 rpm or so. From the folks I've talked to that run the 1243, valve spring life is better and more consistant than their lifters! I'm giving away alot of my secrets here but there's <10 members in this section who could actually use this data so whatever

Wicked94Z

iTrader: (26)

btw...

.750 net on those is about 250/660

stumprrp

iTrader: (2)

doesnt really apply i guess but my limiter is 7000 and although its floating at that point it spins up there with no issues at all, usually during a rolling burnout.

robsquikz28

iTrader: (246)

so only 1 person huh????? lol

Beaflag VonRathburg

iTrader: (176)

I'm more suprised that people are getting away with hyrdraulic setups in the 250/660 range. Like mentioned above I don't see how even a limited hydraulic lifter could keep up with that for too long.

SS RRR

iTrader: (2)

I don't have the ability to datalog, but I'll see what I can do. I'm pilled at 6800rpm, but shift past that. Still using stock tach so no idea exactly where that is.