I am in the process of rebuilding my 83 SB 350 Chevy and noticed the heights on the existing valve springs are different between the intake and exhaust valves. I am replacing all the lifters and cam with COMP parts and tech support asked me to measure the install height from the bottom of the spring to the bottom of the retainer to be able to size the correct springs. Well, they are different as you can see from the photos, and I am wondering why the exhaust has a different retainer/height than the intake? Is that normal? The springs themselves are the same height un-installed. Really weird to see this. Any thoughts?
Looks like you are using different height retainers and or keepers on the valves. I ran into a similar issue on a 389 Pontiac - you never know what someone did on an older engine that has been apart.
Would take them apart - valves could have different stem lengths, seats could be receeded in the head, plus the issue of retainer to valve guide or seal clearance.
Just make sure you have proper retainer to seal clearance (assuming these have been cut for viton seals), check for coil bind, and have correct installed height.
On the engine referenced above when a valve job was done in the early 90's for some reason the exhaust guides were left .090" taller than the intake when they were cut for seals. The stock cam with .407 lift was just kissing the tops of the seals. I was putting in a higher lift cam that on paper should work with stock valve train ... ended up using Comp Cams retainers that were .050" shorter on the intakes with viton seals. Had to go back to the oring seals and splash cups on the exhaust with keepers that sit .020" higher, then had to shim some of the valve springs up for proper installed height as some of the seats were recessed into the head a bit.
Bottom line verify it is right or take it to a machinist who can otherwise you will break stuff