I have an Olds 403 in an 86 Cutlass. I want to get more power out of it but I cant find any 68-72 350 heads, but I can get a whole 330 rocket heads for really cheap. Will they work on the 403? The 330 was made in the 60s and the heads have small combustion chambers so they will help the compression ratio on the 403 alot, and I can do port and polish job to make them flow better. I know the 330 is a rare engine but someones gotta know if this will work

Check this post
http://www.hotrodders.com/forum/307...l?highlight=307

If they will work on a 307 they will "bolt up" to the 403 but will the compression ratio be too wild for the street? The car already has a cam that barely lets it idle, so I want to keep it streetable.

I don't know sqwat about the Olds engines but this post has more Info. Or do a search for more.
http://www.hotrodders.com/forum/rec...l?highlight=307

The 330 heads are virtually identical to the 68-70 350 heads. Watch out for the oddball 64 330 heads that used the one-year-only shaft rockers. You should install the big-block sized W-31 valves in these heads.

By the way, the 330 also has a forged crank with the same stroke as the 403...

Thanks for the fast info! Are the pistons the same hight on the 403 and the 330? It sounds like Im going to get the 330 now, how much does raising the compression ratio a point or 2 help the engine's power?

check the for sale section at www.realoldspower.com for heads. Olds info here http://www.442.com/oldsfaq/ if you see non for sale ask.

Yes, all the small block Olds motors use the same compression height on the pistons as well as the same stroke and same rod length, however the 403 rods are beefier than other SBO rods (not counting the diesels). They will work on the forged 330 crank, but you will need to rebalance. Also, the 64-67 Olds motors use a different crank flange bolt pattern than the 68-90 motors, so you need to use the flywheel that matches the crank if you decide to swap.