Which heads for my 403??

[FormulaMan403]

I have a '78 Firebird Formula with the 403 and I was looking for some heads to swap over for more compression and performance...And I finally found a place that has 2 sets of heads, they have a pair of #5 heads and a pair of #7 heads. Which ones should I go with???

Anyways I can get the heads completetly assembled, drilled for bigger bolts and coolant passages for $300. But I was wondering If I should Have them port and polished first, Is this really a big deal?? or do they flow good enough to not worry about em??

[gearbanger]

Does bulldog make a set for it? What about Edelbrocks or Mondello? There is alot of good parts out there for Olds.

[gearbanger]

Sorry, I didn't read. I have no idea about the factory castings.

[jfmjr1]

try this site

http://442.com/oldsfaq/ofe403.htm#E403%20403CIDEngineDetail

It is from 442.com freequently asked questions section.

Also check section on Heads - will provide all that you need

From what you say your choices are, I would go with the 5's, if they are to be redone, which should be a 1969 (casting number 397742 located above center exhaust port) 350 SB head but check casting numbers and make sure they are 69's. The 7's would also work, and may also already have hardened seats for unleaded fuel

Hope that helps

John