Part numbers wanted for valve springs

BlownMGB-V8 · May 27, 2019, 10:15:40 AM

I expect some of you will have some favorites. I'm looking for a drop-in replacement for the BOPR heads, (specifically 300 heads but the dimensions are the same) that are capable of operating up to 7,000 rpm without being overly stiff. Not looking for beehive springs or something that will require cutting the seats to fit. Just something similar to stock but a bit stiffer. My guess is that there should be any number of SBC springs that would work.

Jim

minorv8 · May 28, 2019, 01:26:10 AM

I have also tried to find suitable ones but usually the problem is the fitted height. Especially if you have even a slightly uprated cam. IIRC Kent Cams do a set of both single (part no. VS44) and dual springs (VS43) but they are pretty expensive. Around £200 for single set and £250 for duals in UK. Duals need machining.

Kent Cams Rover V8 springs.jpg

MGBV8 · May 28, 2019, 08:24:31 PM

I was thinking SBC Z28 springs. Seven grand might be a bit much, though.

How much lift do they have to endure?

mgb260 · May 28, 2019, 08:46:51 PM

The Z28 springs work good with slightly taller valve like the 2.3 SOHC Pinto valves. You would have to lower the seats in the head or use locks to lift the retainers higher with the short Buick/Rover valves. Good to 6500RPM and a little over .500 lift.

minorv8 · May 29, 2019, 12:26:58 AM

Are there Buick type 10 degree locks available with different heights ? Machining the seats in order to compensate short valves / taller springs does not really make any sense.

mgb260 · May 29, 2019, 01:37:10 AM

Jukka, That is why I have always used the taller valves and shimmed the rocker stands to compensate. It also requires longer pushrods for proper geometry. The Buick valves should be 7 degrees like Chevy. I don't know about Rover, they may be 10 degrees.

MGBV8 · May 29, 2019, 11:27:30 AM

These should do it.

https://sdparts.com/i-24132268-sdpc-sbc-1-250-valve-springs-600-max-lift.html

Or these.

https://www.summitracing.com/parts/hrs-98215

mgb260 · May 29, 2019, 12:34:10 PM

These have a shorter installed height and can't beat the price. You would probably need Chevy retainers but try the Buick one's to see if they will work.

https://www.alexsparts.com/sbc-z28-valve-springs-drop-in-fit-500-max-lift-to-suit-stock-sbc-iron-heads/

MGBV8 · May 29, 2019, 12:50:32 PM

Lift & installed height would be helpful, Jim B.

BlownMGB-V8 · May 29, 2019, 11:58:22 PM

Valve lift is .436". It appears 1.727" is the factory spec for installed height, showing 64lbs of seated pressure, so I'd think those last Z28 springs should work, might need a shim to raise the spring pressure a bit. I think I'd like to see something around 120 seated, 350 open. The price is certainly right.

Jim