403 olds ?

hi im looking for exhaust manifolds for my 403 olds, a set that doesnt have the cross over shit and with a bit bigger collector any ideas guys maybe some one has a set or there is a company out there that makes what i want

 

There is a company that makes a neat center drop and a rear drop for all Olds motors. There isn't a small block cast iron manifold that doesn't have the crossover on the right side. However there are aftermarket cast manifolds that look like factory available from a supplier in Illinois. I'm not going to name the company. PM me if you want that info.

 

Olds never made a small block exhaust manifold that didn't have the crossover feature. Even the W-31 motors used these manifolds and simply used a cap over the second hole on the passenger side manifold. There are aftermarket "dual exhaust" manifolds available now, but I suggest you look at them closely before plunking down $300 or so. I've inspected one set of these and they are exactly the same shape as the stockers. They even have the location for the crossover hole on the passenger side manifold - it's just blanked off. Only you can decide if that is worth the price to you.

One other option is that some folks have used the passenger side manifold from an early Toronado. The big block manifold bolts to the small block and only has a single outlet. Finally, if you are using front motor mounts, the driver's side center dump manifold from a mid-60s Olds full size will bolt to the passenger side as well.

 

I have SS Doug Thorley Hedders on my 403 Hurst/Olds in my '78 GMC Motor Home ,,when i was at the MOKAN Drags a couple years ago ,,a guy from St Louis had a '50 Olds fast back drag car with a Hi-Perf 455 Olds in it ,he had a set of Hi-Perf 455 factory cast exhaust manifolds that were like hedders ,,no cross over stuff ,,had em fer sale for $100 bucks ,,said they's bolt right on a 403 ,,not sure if all he said was true ,,but sure would be werth your time to check on eBay / craigs list ,,or where ever for a set of those ,,sure would solve your problem ,,

 

Another option is to use two left side manifolds. The one you put on the right side will exit at the front but if there is no obstruction, it will work.

 

thanxs for the help im still cruisen the net and trying to find something that will work good this motor is going in my 53 belair and im runing the stock suspension in the front so i dont have alot of room to work with so i would really like to find a nice set of manifolds that will work

 

He would be wrong. The 403 is a small block Olds, based on the same short deck height as the 350. The big block Olds manifolds will bolt to the small block heads, but they won't clear the motor mounts, oil filter, or starter. The big block's taller deck height is how Olds was able to fit these individual runner manifolds on those motors. As I said above, even the highest output factory small block, the W-31, used the crappy crossover manifolds. If the hi-perf W/Z big block manifolds had fit, Olds would have used them from the factory.

 

i just replaced the passengers side exhaust gasket on a 403 in a GMC motorhome, it had no crossover as i recall but had a funny notch which could be cut out and filled.