C heads fit on a 403 olds?

[fleming442]

Did you call Bernard or Mark yet? I wouldn't chance some fly-by-night used car salesman.

 

[olds307 and 403]

Problem with milling heads so much is it makes them harder to work a piston change or on a different motor. I have a pair of #6 heads milled to 55cc, 2"/1.625" valves, filled crossovers, positive seals along with bowl and port work. With my 403 stroker plans I will need to polish in a lot of CC to use them, a lot of my time. I would go more like 65cc max, that would put you just over 9 to 1. Problem is with off the shelf, quality replacement pistons with 65cc chambers will put you at 11 to 1 compression, if it needs rebuilt down the line. The quality replacement pistons are meant to work with stock or big block heads, only weak, old school ring pack, short on compression height cast replacement or custom pistons in an oversize would work in a total rebuild. The big block heads, other than the J heads are all very close to the same for flow. Iron heads have you need a good deal to bother buying a set. I paid $400 for a set of totally rebuilt 62 to 64cc #6 heads with new 2.05"/ factory 1.56" valves, cutter used under the valves, upgraded springs positive seals and new guides. I pulled a couple of valves, everything checked out. Deals are out there. Remember big block heads will CC at 80+, not far off your stock heads. Early 330/350 heads with 2.07"/1.625" valves with a cutter used under the valves to open the bowl will be much better than 4A heads. They start at 64 to 70cc chambers stock, giving you around 9 to 1 compression. Neither will flow what Procomp's flow without a lot of work. Another thing I would use with aluminum heads is MLS head gaskets. Cometic, Mr Gasket make sets for the 403. Supposedly SCE is coming out with a lower price set. The current MLS head gaskets are $100+ each. I know Cutlassefi and Bernard both can probably get those Procomp roller rockers at a very affordable price. Cutlassefi is very competitive as is Bernard on parts pricing. Both guys also do many Olds builds and actually have a clue what they are doing. There is nothing wrong with Chinese parts, if they are the right ones and also properly inspected and built with quality parts in the case of the Procomp heads.