Olds guys, I need opinions on these heads

[olds307 and 403]

I would also take a grinder to those Thorton manifolds, supposedly far from ideal as cast at the port openings and exits.

 

[Streetbu]

Read the title as Old guys, I might need new reading glasses.........

So did I! LMAO

Not sure if anything has changed but, I've always heard that Procomps are actually good heads as long as you buy bare heads and have the machine work done locally.

 

[JAMCAR223]

Pistons are undecided, due to different chamber volumes between these heads.

The main use of 330 or early 350 heads is an easy compression boost on a stock 403 short block, same for a 350. Also the Procomp heads as cast are 83-84cc. Even with flat top pistons in a 350, 9 to 1 at best with tight quench. Procomp should offer the head as cast with a 70ish CC chamber and a blended port opening version with the larger chamber for the BBO. Honestly like Edelbrock offers for Pontiac, there should be a 67cc chamber option as well, we are not a big enough market unfortunately. I don't know if Olds Rocket Parts is going off the 77cc spec and doing a .060" cut, thinking so as their 69cc head actually measure 73cc I believe. That will give 10 to 1 with KB pistons. The Edelbrock head is definitely superior as cast with 265 CFM intake, arguably a better chamber shape and with much better parts but double the cost and still only one chamber option. With the .060" head mill, your intake will definitely need cut, another good reason for a smaller as cast chamber, nothing is bolt on like the chebby world, SBO stuff especially.

Well said, and agreed.

 

[Jeff Blagden]

Olds 307 403 is a wealth of knowledge for this thread

 

[olds307 and 403]

Thanks, Oldsmobile is my passion, the SBO especially, very underrated. I can still find mid 70's Olds 350 that run very good, nearly everything else was junk from that era with over 100K, Olds no problem with twice that.