well ive been to parts stores and cruised the net looking to replace rusted out header on 1974 hilux 18R-C. nothing. Any resource for aftermarket out there? or even used manifold? many thanks.

 

pacesetter made one, now NLA, need to find NOS for header. for Manifold, Offenhauser makes one, I think it's still available.

 

Try this search engine, it dig's through all the salvage yards. I would call and confirm a match before putting your $$ down. If you find a new one let me know where and how much (if you don't mind), I've been looking too. It seems the rarity and unusual nature of our single side flow motors makes it hard to find AM parts for the head.

Car-Part.com--Used Auto Parts Market

EDIT: (addition) Is that your '74 in your avatar? It looks just like mine from what I can tell-is yours sort of a fading slightly starting to rust blue? Maybe we should form a '74 alliance and show these I got a newer truck haters what it REALLY means to restore a classic (which are obviously pretty rare these days).

 

in australia the 18R-C was very very common as all hilux, hiace van, celica and corona had them from 1974/76-1984. we never had the 20R nor the 22R except for a rare few, freight although might not make such worthwhile.

as example
TOYOTA 18R/18RC CELICA/HILUX/CORONA FET WEBER MANIFOLD | eBay

if you were willing you can get whatever you want, so often aussies do the reverse.....

edit, both these places make adapters to fit whatever engine in and too near on any gearbox "transmission" in any car.
Castlemaine Rod Shop
Welcome to Dellow Conversions
otherwise the part you seek is very easy to obtain here, just google it .au

 

try checking out some first gen toyota celica fourms or other old toyota site sorry its super hard to find header and intakes for the 18rc a dime of dozen for the 20/22r

 

have an extra 8-rc

Not an extra 18rc.

Are they inter-changeable?

 

It appears they should be inter-changeable, as the only real changes between the 8RC and 18RC are: 18RC is bored out 2.5mm larger, it has several emission systems absent from the 8, 18RC has a different carb (has solenoid), some minor differences in valve train, and the 18RC is slightly shorter. Both have the cast-iron head and share many, many parts-so should fit. But can't say from first hand experience.