Gordon, I have them both ways, meaning with stock manifolds and with headers. Just about everyone loves headers but if you might be selling the car and the car as you stated is pretty original your best bang is to put stock manifolds back on IMO.

 

Thanks, Chick, I'm inclined to think that way. Selling the headers will just about pay half the cost of the transition to make it worth it. Then the car will be practically 100% in original and added factory options condition.

 

Checking into the exhaust manifolds at Classic and a great price at 20% off this weekend whereas the others don't apply the discount to manifolds.

Just a question.....should I get the heat riser, too? Also should I be putting on those locks for the bolts?

 

If your going to change it Gordon, then I'd suggest changing it back correctly.

 

You don't need the locks, and leave the heat riser out no one will notice. There are lots of used ones out there. I love the look on mine.

 

I replaced my headers with truck rams horns.. gave significant bottom end torge increase...and still a very nice engine sound..
With cast manifolds and a good 2 1/2" duel exhaust system one still retains a nive sound...many comment better because it removes that 'tink' tin sound of the headers.
I have also noticed the same on sbs with std cast manifolds.
If the engine is a basically stock, or slightly mild cruiser u will alsoi notice a significant increase in bottom end performance/ economy... in spite of the marketing /propaganda BS ... the reason is the longer runners are more efficient yes, but designed for higher rpms band... outside that one tends to get scavenging of the mixture shot... ie that 'pool' of higher concentrated mixture that sits on the top of the valve just before opening, get pulled thru and out the exhaust valve before the Ex valve closes at lower cruise rpms.
So dont right off cast manifolds quite so quick because of marketing propaganda BS.....they do work...like headers in the right application...
And when cleaned up, all the dags casting bits not needed, smoothed off and painted do look the part of a nice cruiser engine

 

Now I feel better about going with the manifolds. Will stop at my exhaust specialist today and see if he'll supply the downpipes. Or if I should order downpipes from Jegs or Summit? Spacing is the critical thing here.

As for the spacer, it would be either the spacer or the riser, correct? If I didn't have a riser I would put in a spacer. But if I have the riser, then no spacer is needed, I think?

 

Is the rest of your exhaust system factory correct? If not, in my opinion reproduction exhaust manifolds combined with a muffler shop or aftermarket exhaust system aren't any more desirable than headers.

 

The rest of it is factory correct back from a little forward of the axles to the 2 shiny chrome tail pipes coming out. So, I'll need to have the correct piping in there between the manifolds and the rest of the exhaust system.

I imagine my exhaust specialist can either make them to specs, or order the downpipes in. If I order them myself I might be messing it up due to spacing with the heat riser and that connected.....??

 

I learned something new about the locks and outside bolt torque after doing some research. Very interesting. Guess I will be adding those.

 

"Very interesting"? You've made me curious, so if you could elaborate on that, please....

 

I found this on a search:

SBC's & BBC's used the locks on the front and rear bolt pairs only. The reason GM put them there, is that the end bolts aren't torqued to the same spec.s as the centers from the factory and the end pairs would loosen in service if the locks aren't in place.
This fact is not known by many and it is the reason manifold cracking is such a problem - not from the factory, but after someone services the engine and retorques the end bolts to 30~35-ftlb's same as the centers. Next thing you notice is the manifold is cracked at one of the ends a couple months later.
GM fiqured this out after they took the gaskets off the exhaust manifolds back in the early 60's and went to just surface to surface contact on the heads/manifolds.
So, if you are using the stock manifolds and want them to last. Torque the centers to 30~35-ftlb and then torque the end-pairs to 15~20-ftlb and bend over the french-lock tabs to keep them from loosening. This will allow the manifold to 'grow' a little towards the ends when hot and not crack...

 

I imagine my exhaust specialist can either make them to specs, or order the downpipes in. If I order them myself I might be messing it up due to spacing with the heat riser and that connected.....??

It is best to get custom fitted to the current exhaust system...
My casts where used, therefore the studs rather corroded...couple snapped off.
I ground a taper into a bolt then welded that tp the stud in the flange, then while hot gently wound out the old stud...some of the threads where not in good condition so drilled all the holes out and re taped next size up...new studs which once wound in where held in place with a small mig spot weld.
The pipe from the bottom flange is thick walled.. this was then able to be expanded/ bent and internal stretched to fit the larger 2 1/2 " pipes and welded in place.
Keep the bottom bend as high as possible, dont allow to hang down below the chassis level at that point...If u happen to roll off a kurb, or similar type action, and hit the pipe, chances are u will crack the cast manifold.

 

You might consider getting them ceramic coated as well. Just a thought, eh?

capt