Guys, can anyone tell me if I can get any flat top pistons for a 403 ??? And, if so would the 7a heads off a 350 fit the 403 ???

I,be been on speedpros website and they only mention said pistons for 350 or 455s

 

Here's a flat top piston for a 403;
https://www.uempistons.com/index.php...bd59cdeb4cc379


With a stock 7a head it will yield approx. 10.7:1, probably a bit high for an iron headed application on pump gas.
And to get those heads to fit you'll need to drill out the head bolt holes to 17/32 and I believe enlarge a dowel hole as well.
Just an fyi, this should be in the small block section, not big block.

 

Cheers mate, out of interest are you running a 350 with an Eddy airgap intake ? We,re gonna rebuild the 350 now with flat top pistons, any suggestions ? PS if I was any good with computers I would move this to the small block section, but I ain't.

 

The 403 with the pistons Mark listed would be great with Procomp aluminum heads. You can use cast replacements with the 7A heads for 9 to 1 compression. The 403 is a small block, just so you know.

 

Any chance of giving more info? Gear, car, tranny, the rest of the combination, wants etc.

 

Not sure of gear ratios, how do we find out ? I know the car is just about standard in all respects, 3 speed auto, 350 rocket, is your intake a performer airgap ? I can't see these listed anywhere for an olds s/b.