Mr MasterCraft

I read that with the Comp 918 springs, the valve seats on the heads need to be machined so the springs will fit correctly. Also, on TSP's website it sates that with the .700" springs, the heads need to be machined to get those seated correctly as well. My question is, do the heads need to be machined to get the .650" springs to seat correctly as well? I'm working with factory 241 heads, and have already installed the new .650" springs on one cylinder head already. They've been pulled as I decided to install the LS7 lifters at this time as well. I'm also using factory retainers, as none were included with my "cam package" for whatever reason. Any helpful insight will be appreciated, thanks!

TVWilkes

No machining is required to the heads for the .650 spring kit. The PRC .650 springs will not work with the factory retainers. You must use all of the PRC parts. If you didn't receive any retainers, call TSP asap!

lemons12

iTrader: (71)

I used factory 98 heads with my .650 PRC springs.

01ssreda4

iTrader: (96)

918s do not need machine work for them to fit.

farmington

iTrader: (14)

and the 918 springs will work with factory retainers and locks

Mr MasterCraft

Damn, that's interesting. I'm doing a MS3 swap in my C5, and when I looked at the C5 how-to H/C tutorial when I came upon problems removing the steering rack. Whoever typed it up, said that the GM heads had to have the seats machined to fit the Comp 918s?

At any rate, I'm going to call TSP here in an hour when they open, Aaron has been nothing short of outstanding so far.

NVR_SPDS

iTrader: (39)

918s are drop in. They do come with a base/seal, but they use the rest of the stock parts such as retainers and locks. NO machine work required. I had 2 cars, both with 918s.

Also, I just installed the PRC EHT .675 Duals on a set of untouched 799s, no machine work required. They came with all the neccesary hardware, such as spring seats, valve seals and retainers, but re used the stock locks.

Mr MasterCraft

I got ahold of Aaron, he said I was fine with using the factory retainers, and was very helpful and informative with my 10,000,000 other questions I had!

Sales1@Texas-speed

^Yes our PRC .650 spring kit uses the factory locks, but comes with new spring seats, valve seals and retainers.

z99ls1

iTrader: (12)

He told you it was ok to reuse the factory retainers? or did he tell you it was ok to reuse the factory locks?

Sales1@Texas-speed

^I told Mr MasterCraft it was ok to use the factory locks.

Mr MasterCraft

Locks yes. My fault