I have an Edelbrock RPM cam, specs are 234/244 @ .050, .488/.510 lift. I currently am just using z28 springs on factory 882 heads.

I want to run 1.6 rockers with my new World Product S/R Torquer heads, but could use some educated advice regarding springs. Edelbrock recommends their Sure Seat valve springs:

1.7 installed height, .510+.050=.560 max lift, 120lbs inst. pressure, 330lbs @ 1.180 open pressure, 1.130 coil bind, 1.130 o.d. diameter.

If I run a 1.6 rocker, lift increases to .540, so add .050 = .590 max lift?

The spring specs on my World Heads are:

1.250": 110 lbs. @ 1.700", 300 lbs. @ 1.250", coil bind @ 1.160"
MAX LIFT @ .500 (specs from Bill Mitchell)

Which are inadequate I believe.

Would these springs work? There are some AFR 8020's for sale here on TGO:

1.437 OD 125# @1.800 pressure, 1.090 coil bind, 320 rate, 550 lift (specs from AFR)

If someone could point me to a proper valve spring for my application I'd appreciate it. Edelbrock doesn't have a spec for using a 1.6 rocker, so I'm trying to use the specs given for 1.5 while allowing for extra lift of the 1.6 rockers.

Thanks.

 

Heads are at 1.700" install?

Afr's will work if pockets are cut large enough. I would consider +.050 locks so height is 1.750"

 

According to the website spring pockets are cut for 1.5" springs. I dunno if those 8020 springs are still for sale, any ideas or part numbers I can look for that will work?

 

Gm ls6 springs or beehives are popular upgrades

Manley 22410's are a great single spring that may drop right in. They may be slightly to much seat pressure at 1.70". They call for 1.75 so offset locks would be nice here. Then you gotta watch rocker arm to retainer clearance as offset locks move retainer up. May need lash caps which are no big deal but added expense

 

Thanks Orr, I actually just was able to purchase the 8020's. Hopefully they will work.

 

Yeah they should fit but make sure to measure install height on those heads first. If its 1.700", then you will want offset locks. If there are any factory shims on head remove them to try to get height closer to 1.78-1.80 that the afr's call for.

If not that seat pressure will be 157 lbs which is alot for flat tappet. Not terrible for aggressive rollers but i believe your cam is a flat tappet?

 

Yes it's flat tappet, I thought the seat pressure for the 8020's were 125#?

 

Yeah when installed at 1.800". If installed at 1.700" you gotta factor in 0.100" difference on the spring rate, which is 320 lbs inch. So .1 x 320 is another 32 lbs added to seat

 

With all that said I would not bother with that much lift on factory 882 heads.

 

What happens if I install them at the springs recommended 1.8 instead of the cams 1.7?

Looks like I need to find a book.....

 

Swapping out to World S/R Torquers...

 

Are you porting them?

If not they lose flow after 500 lift

http://www.worldcastings.com/engineb...adflow2010.pdf

 

Yes, I'm having some port work done. Mainly in un-shrouding valves, bowl blend and clean up the valve guide bosses. Gasket match. Nothing fancy. They do fall off over .500 lift in stock form, but I've read that they respond well to some mild porting.

http://www.caspeed.com/488hp383.html

 

See if you can get them at 1.75-1.8". Spring specs will then match afr's listing