820 heads

[Z28SSMAN]

Hey Bob, I'm thinking I'm gonna look for another 820 head to closely match the date code on the one I have.
Not as good as 049 or 781 but I want to use the ones that came on it in '71.

interesting threads on 820 heads

Those heads are from the Vette/Chevelle LS-5 units. We've done a number of these over the years, and still do today, on our 100%stock-appearing builds.
Factory valve size, 2.060"/1.720", on our builds we use some SBC intakes,2.150" x .343" stems, and stay with the 1.720" exhausts. They do flow decent and handle 525/550 HP on these resto's with a 4.250" crank. These are non ported, just very minor bowl work. All have the Q-jet carbs. The average flow is 290/190 CFM @ .600". As stated, non-ported.
Thanks, Gary in N.Y.
P.S. CC's run in the neighborhood of 112 finished. This is a "nominal" number, we've had them with 110 and 113.

820 heads are a good flowing head . Semi open chamber . They were on the 402 and 454 from 70 to 72 . I have a 402 made to 413 with 23 cc dome pistons and no issues . Open chamber heads need open chamber pistons and closed chamber heads need closed chamber pistons.

https://www.chevelles.com/forums/13-...820-heads.html

https://www.youtube.com/watch?v=uoTL6SG_i8o

https://www.camaros.net/forums/18-en...-question.html

https://www.speed-talk.com/forum/viewtopic.php?t=40690

[MR.hp]

When we get them done that 454 will still run in the 11's.