OK, there are several older threads discussing this but is there anything new in valve springs for a 500 EFI camshaft profile? What springs match the recommended installation specs and will last FOREVER?

nothing lasts forever.

Yup

Isky Tool room series is a great spring.

comp cams 929-16 will work great we have installed hundreds without any problems

I have had excellent luck with the ISKY 8005A. Have done them on more 500 efi's than I can count. I sell dozens and dozens a year to owners of 500's.
Eddie

It sounds like there is nothing new in valve springs. But I have questions on the replacement springs commonly being used. The cam card for the Crane 169621 lists the spring requirements at 150 lbs at 1.900” and 454 lbs at 1.310”. The Comp 929 as I understand it was used by MerCruiser in the production 500 EFI engine for several years. It typically has an expected life of 200 to 250 hours and has 139 lbs at 1.900” and 397 lbs at 1.310”. Is the lower spring pressure acceptable due to the lower RPM the 500 EFI runs vs. the max RPM for the 169621 of 6500? The Isky 8005A is an even lower rate spring with 125 lbs at 1.900” and 361 lbs at 1.310”. How soft a spring can assure the roller lifters never leave the cam up to 5400 RPM? Are these softer springs set up to compensate for the lower rate, lower installed height without getting into coil bind? How long is the 8005A expected to last on this cam profile? It looks to me like the Isky 8205SP and 8205Plus would fall into the acceptable spring rate range with improved longevity, both have 150 lbs at 1.900” and 409 lbs at 1.310”. Does anyone have any experience with these two Isky Springs on the 500 EFI cam?
Thanks.

I know JimV sets up a lot of heads for hydraulic rollers with Comp 929 springs.
Also if Eddie Young uses the Isky 8005A I think you have 2 good choices that are proven.

There is no reason in the world to have over 400 pds of spring pressure on a 5400 rpm 500 efi. Put the 8005 ISKY's in at 1.870-1.875.
Eddie

What are the best head gaskets for 500 EFI?