1972 big block exhaust manifold

[MilkyNoSugar]

My engine rebuild is almost complete, but a small crack has been found in one of the exhaust manifolds






Just in case the repair is not successful, does anyone have a manifold available for a 1972 big block? I believe its the passenger side I need but need to check that with the engine builder.

 

[Roscobbc]

Ordinarily I'd say fitting headers to a stock big block is perhaps a waste of time (as the stock items arn't that bad).......except that I did put headers on my then stock (other than a Holley 750 carb and Torker inlet) 390 hp 427 lump. An unexpected benefit was a cooler running engine and underhood temperatures.
However being as you have aftermarket heads etc fitting headers could 'round-off' all that engine world and allow a few more HP through. Theres a few choices out there - if choosing be careful of the larger tube 'race' style headers as they 'hang' very low in the chassis.

 

[MilkyNoSugar]

If money were no object then it would be having new manifolds, but right now I need to manage the costs where I can. The heads were an unexpected expense on this rebuild, and I could do without the costs of new stainless manifolds regardless of the benefits I know they bring. That can be a phase 2 upgrade next year....

 

[Roscobbc]

Welding cast iron is problematic I'm sure + and perhaps only by skilled welders. Wonder if it's feasible to drill a hole each end of the crack (to stop it spreading), grind a small channel between the holes and over the crack. Then fill with weld.

 

[MilkyNoSugar]

that's what is being attempted at the moment, and as you say, welding cast is a challenge

 

[Roscobbc]

that's what is being attempted at the moment, and as you say, welding cast is a challenge

Best of luck!