Just make sure they have thick flanges on them.
Do the heat cycle thing and like Eric said use the Remflex gaskets.
I have used headers on my big block truck and they fit in there like they were built for it.
They are a set that was intended for a Nova.
You will need to attach your current exhaust to them.
You will need to adjust your carb mixture due to new efficiency found from cylinder scavanging.
You will enjoy all of the things
@Rusty Nail pointed out.
We put headers on the truck and it went from wienie to hero like a Charles Atlas cartoon advertisement.
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Dirty old headers from a buddies project car that he no longer needed these for...
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When we first installed them it was with the stock Q-jet and stock low-rise intake.
Just the headers changed the whole attitude of the engine.
No other changes made at this time and it drove like a champ.
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Now we have come along even further with this 454.
It has an Edelbrock Performer 2.0 intake and is topped with a used rebuilt Holley 750cfm carb that I pulled from the swap meet. Junior put some parts into it to the tune of $160 and for just $200 we have a totally serviceable carb and whole spare jet set for fine tuning to boot!
The engine is still fairly mild, but miles more fun to drive.
It has way more power everywhere in the power band.
I was driving it the other day and forgot to put it back into 2nd (manual transmission) at a light to take off.
It pulled away with no issue in 3rd from a full stop.
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