Freshing up the heads on my 575SCi's and adding Whipple innercoolers. What should I use?? Merc or aftermarket and what brand/part number?

Thanks

Isky valve springs.

are the stock springs a gold color or black??

Black with yellow paint marks

Ttt?

I think the black springs from merc are the Comp cams springs, they had an earlier design then changed if i remember right, they should be good to run unless you are changing to bigger cams or turning more than 6000 rpms

Thanks Mark

I talked to the Comp Tech line yesterday. The closest they have to stock spring spec. is P/N 924. It has a lower seat pressure and lower lift pressure. It's not a direct replacement and I will have to get new retainers and locks. The Whipple kit includes remapping the ECM and raises the rev limiter to 5600 from 5300 rpm. Seems assbackwards to raise rpm and lower spring pressure

Anyone with some first hand experience? Thinking stock Merc springs might be the easiest.

Thanks all

Call isky and try the 8802 springs

what is your seat pressure, i would think about 145 lbs, i know you dont want much over 150 seat pressure with a hyd. cam

i am using the crane springs on my 500efis Part Number: 99895-16, they also have an updated spring av. as Part Number: 99896-16.