Interesting post here.. I'm sold on PAC..


Yeahdoug wrote:

Lem Evans wrote:221424-16 Manley Nextex . Erson spring looks to be the same unit....blue stripe deal .



Some fatigue test data I did comparing the 221424 polished and non polished to our PAC-1224/1324 (our copy of that spring with our own flavor of processing).


These are the cycle counts for the first failures of each part. All springs were tested to the same 1.300" stroke (overstressed to induce failures).

Manley 221424 STD: 4,995 cycles.
Manley 221424P Electro-polished: 22,277 cycles.

PAC-1324: 866,530 cycles.
PAC-1224: 571,668 cycles.



Yeahdoug,



Here is the whole thread..

http://www.speedtalk.com/forum/viewtopic...726b3399799cfa1



Chris..

Sounds familiar,,,Engine Works, available @ Nickles Performance in Tenn. #985-16 spring will get you about 225# @ 1.95". I have used them alot on small block Chev. They will go around 680# open and are good to .720" lift @ 1.95". I will have to look later,, but I think the #987 will give you more seat pressure with similar open pressure. Possibly a + .050" loc with the 987 to get where you want to be. I have had good luck with the 985 for years, usually good for a season on dirt track motors. Probably a LOT more on drag applications. Forgot to add, VERY affordable @ $200.00+- few bucks.

This is the Crower Ti retainers I used with the 1225/1325 PAC springs:
Crower #86067D-16. 1.500 od, 0.725id, cost $239.95 from summit racing.

http://www.summitracing.com/parts/CRO-86067D-16/

comp 943 springs set at 1.950 are 235-240 on the seat ! ive got a roller cam 720 lift, got 4 years of racing and street driving work perfect 9.60s at 141.75 and they don't wear stuff out and no broken parts !!!!!!!!

The springs on there where Comp 1.550 roller springs, I don't remember the number, sorry. They have lost between 25 and 30 lbs pressure on the seat(275 lbs. to 255) and over the nose( 675 lbs. down to 250 lbs), which is probally no big deal on most motors. This motor broke a 3/8x.083 pushrod during the first set of dyno test, it also hurt the cam and broke the top off of one set of rollers. I fixed the motor and ended up replacing the 3/8x.083 pushrods with a set of 3/8x.120 wall Manton sereis 5 during the next dyno tests, the pushrods made 8 hp more and 7 ft. lbs torque gradually from 4200 all the way up to 6500 RPM. This leads me to thank, especially after talking to Terry Manton, that a bigger, stronger pushrod is needed along with some more spring pressures. The cam lobes are capable of 9000+ plus according to the folks at comp Cams Hopefully I'm not a dead horse The rockers are a set of T&D 1.65 ratio on both sides. The new springs are on the way and I will dyno it again to see what is does after freshening it up. It burnt two pistons up on the last dyno session,but that is another story.