Coil spring help

I can not for the life of me find the spring rate of the OEM coil springs. 05 tacoma, access cab, prerunner, 2.7 5 speed. I'm trying to buy new springs for my walker Evans 2.5" coilovers, I know that 600# is way too stiff but I'm not sure if I can run a 500# spring and if so if I should stay with 12" or go to a 14" spring.

 

I have 650's and it doesn't seem stiff at all. A bit too soft off-road IMO. I've got the V6 DC though...

I can't remember, but the stock rate is ~550ish. 500 is going to be really soft.

 

Based on the part numbers at the bottom of the post here:
https://www.tacomaworld.com/threads/stock-tacoma-suspension.50395/#post-900676

And looking those part numbers up here:
http://www.toyotapartsoverstock.com...-EUCPNC51405A--51406A/3951649/48131AD241.html

The prerunner 2.7 and 4.0 use the same coils. These do not appear to be the same coils as the 4x4.

Looking at the mass spec sheet, you can see there isn't much weight difference between the 2.7 and the 4.0, but there is significant difference between the 2wd vs 4x4.
http://www.toyota120.com/GenDocs/2005_Tacoma_s.pdf

As mentioned stock 4x4 is about 550 for reference. Perhaps one of the vendors could help? When searching I saw a few posts where prerunner owners got help from Toytec and Wheelers, though they never posted the answer of what the OEM coil rate was.

Do you have a prerunner?

 

Yes.