Went thru some parts and found some factory 587 heads with a 2.05 intake. Not from factory but from Ryan during the good days. Any significate HP gain over the factory 2.02 with s 525 lift cam?

My guy just did this on my modestly prepped eddie heads( 2.02 to 2.05 intake valves) he saw 6-8 cfm at the lower lifts we were focused on( cam is 565 gross lift)
Figure hopefully another 12-15 horse realistically

Probably getting to the point where you got to consider bore size, too big of a valve gets closer to the bore and starts shrouding it more than helping. What bore size you talking?

My head adapter on my flowbench is 4.015 and I run and test all the time with 2.08 valves with almost zero effect. Figure most guys are running 4.030 at least.

I asked Ryan this question back in 2017 his answer:

Not enough gain to make it worth spending the $ to do it by itself.......


Maybe 5-8 HP?

When Ryan freshened my ported Edelbrocks years ago he replaced the 2.02's with 2.055's. He said they may pick up 6 or 7 cfm.

In some cases the increase in flow can be attributed to a fresh or better valve job and the seat being higher into the chamber with a bigger valve. Sunken valves tend to hurt flow.