572" KB block, 4.5" Callies crank, 7" Oliver steel rods, 11:1 Diamond pistons, pump gas
CNC ported MP aluminum heads by MCH
276°/284° at fifty, .672"/.651" lift, solid roller (spec'd by Fast68plymouth), PAC 1243 springs, DLI roller rockers, Manton .134" wall pushrods
Barton single 4500 manifold, 1200 cfm Pro Systems dominator
TTI 2.25" pri., 4" collector headers, 4" exhaust
727, 9" 5k stall, 4.10 gear Dana 60, Cal-Tracs, 295-65 drag radials

N/A it has run 9.54 at 140.4 mph, 1.320 sixty foot. That was on pump gas at about 3800 lbs.
On about a 225 hp hit of nitrous it went 8.91 at 150, 1.310 sixty foot (delaying the hit) at 3900 lbs.

Just something to look at. The 2 shaft rocker systems, even SV are hard pressed to keep oil on the intake springs at idle, and low rpm. Even reved there isn't much there. Heat is what I've seen break springs more than cycles,(save coil bind) and really high rpm stuff that would never be street driven anyway. Maybe consider a spray bar to help keep them cool.

My personal spring choice is PSI. PAC also makes a great spring. would only run these two spring makers period.

Dwayne I have a crane solid roller in my 426 with 200# closed 455# open lift in 587 ex 568. Calls for .020 lash hot set at .012 cold aluminum heads cast block. Street driven. How often should I change out the springs?

Thanks Mike

Wow thats awesome....looks like the 5k stall/caltracs and 1200cfm makes a big difference compared to mine....when i get it together i am dying to find out what mine will do......thanks

Your problem on a hemi depending on the car it is in is going to be removing exhaust springs on the car. LSM may make an on head tool as well as Buxton

http://www.buxtonengineering.com/on_head_valve_spring_compressor.php

FWIW when I ran a Hemi we had spray bars for just the reason DT is referring to. For what you are doing you wont find a set it and forget it option for sure. But would be nice.

I would run the PAC stuff personally. I could be biased as my brother in law is a big wig at Peterson Spring, the parent company But I do feel they make the best race springs out there, coil, valve, torsion bars and so on

My stuff was a KB block B1 head deal. Hot lash was .016 on both..My current Predator is a World block with about .003 cold and .022 hot. I have another KB B1 engine as well that has .028 hot and .012 cold.

is there a post to see how and where to buy spray bars....that makes sense......would like to do that
i am going with PAC....thanks

We made our own that were epoxied into the valve cover.

yeah i souldve never sold my spring compressor ..that buxton setup looks like a fine tool but not for tight quarters...the one i had bolted off the stands with 4 bolts and was tight on the exhaust but did work.....i dont know why they stopped making them....yep going with PAC.....thanks

Obviously there is no hard and fast rule for this, as a lot of it would depend on how the vehicle is used........ How many runs down the track per spring cycle, if it's run into valve float at all,
whether it's lots of high speed interstate driving, or mostly around town and back roads, etc....... Along with the quality of the springs being used.

Do you know what brand and part number springs are in the motor now?

Since it's so much "fun" to swap out valve springs on a hemi with the motor in the car, I would use a pretty tame set of street friendly lobes(like you have), and the best springs I could put in it, to extend the service interval as long as possible.

The Buxton and LSM spring compressors both bolt in to shaft bolt holes..Was yours an old MP deal? Would not be hard to make one really

no its all stage v....stands and roller rockers

Those both bolt to stands or shafts, IF they make one for that head. I would imagine Buxton does last I checked LSM did not but that was a few years ago. I have both and they are very good pieces, inner fenders are the issue Only way to find out is give them a call

ok....thanks ....my inner fenders are the problem.....this would be fine if i pulled the motor.....that looks like a stout beefy compressor.....this was the tool


[img:center]https://goo.gl/images/vPjieB[/img]

LSM SC330 says T&D rocker on a Hemi..

http://lsmproducts.com/lsm_products/valve_spring_compressors

thank you

Just another thought on the spring choice......
I would use the PAC 1344 instead of the 1244, especially in this application.

The 1344 is the nitrided, higher endurance version of the 1244.

i almost called John at Bullet Cams to order the 1244"s....glad you mentioned this.....thank you

Not sure on the springs The float on the cam is 8200 max power rpm 7600 I have the shift light at 6500 and rev limiter at 7200. It has plenty of pull left at 7200 but with a 4 speed I wanted to play it on the safe side. I try to keep it around the 6500 and most times it's only running 4500 tops.

I guess "if it were me", I'd probably pull a few intake springs off at around 4000 miles and test them for pressure, as well as look at the overall condition of the shims/retainers/locks to see if there are signs of "unhappiness", and make a decision on whether to replace the springs at that time based on what I saw.

To put the OP's situation into a little perspective........ Using very rough guesstimates.......
10,000 miles, at an average speed of 50mph is 200hrs.
If the average rpm over the entire 200hrs of use is 2500rpm, with the cam running at 1/2 speed(1250 cycles per min), 60 mins per hour(75,000 cycles per hour), for 200hrs...... That's 15,000,000 cycles.