Shoptalkforums.com

Hey guys! Started assembling my heads and the Cb HD springs I installed just didn't seem to fit into the head right. Is it necessary to clearance the base somehow?

They may be "Chev" diameter which can be used but only after flycutting the spring seat out. Gene Berg used to sell 1.4374" (36.5mm); CB Performance sells some that "drop in" to the stock diameter seat as well as some that they say are 1.440".

Which CB P/N are they?

What retainers are you using, and do they fit snugly into the springs?

Cb 1490. Title Reads "1490 Single Hi-Rev Valve Springs - 40hp-later (set of ". The retainers/keepers are the basic chromoly one's offered on CIP1.

Ad says "Replaces original parts perfectly."

I'll grab some picture's of them installed for reference.

Those should be stock diameter (so "standard" O.D. retainers should fit them fine). OEM springs typically measure around 1.23" O.D., I think the "nominal" size of the stock spring pocket is 32mm (~1.25") - 1¼" O.D. spring shims fit snugly in them.
The inside diameter should come close to rubbing on the guide boss - that'll keep the springs centered, which is why some hacks have managed to fit "Chev" springs to unmachined heads and just let them chew their way in...not smart, especially without a full-flow oil filter

If yours measure bigger than 1.25" O.D. it may be that CBP's supplier made a bad batch and they weren't caught before packaging - you want the retainers to fit snugly, if they can move laterally inside the spring I'd send the springs back.

It's good practice to always use a steel shim between the spring & the head, especially with stiffer-than-stock springs. Doesn't have to be very thick, say .015-.020".