[Tom Charron]

I am in the process of restoring a 72 Challenger. It currently has a 340 4bl with old rusty headers. I would like to restore to factory original as possible. Question. Did the 340 have a performance exhaust manifold or is it the same manifold as the basic 318 you can still find in wreckers?

[Jack T]

1971-74 318 ex manifold part #3512076, casting #3512077. 1971-1973 ex manifold part #3418624, casting #3418623. I'll say they're different.

[dave-r]

Jack is correct but just to add a bit more information;

Passenger side and drivers side have different part numbers and casting numbers.

The 318 engine used three different castings from 1969-1974. Sometimes it was just different on one side only. Non of these fit the 340.

Same with the 340. The casting numbers changed on one side or the other at least every year from 69-73.

The year you want (1972) the 340 casting numbers are 3418623 for the passenger side and 3418621 on the drivers side if my notes are correct. I am not hot on small blocks!

Happy hunting Tom!

[tom Charron]

Thanks Dave, I forgot to mention my motor is not original. It is a 1969 340. Do you have the numbers for this year?

[dave-r]

I would use the castings for that year Challenger anyway so that it looks right in the car but 1968-1970 castings might be easier to find.
2863553 drivers side and 2863549 passenger side.

[Jack T]

I have the same thing going on - a 1970 340/4bbl in a 1972 car - it makes a world of difference due to the detuning that happened on the 1972 model year. The part numbers are 2863552 (driver's side) and 2863545 (passenger side) for 1968-1970. Good hunting!

[Tom C]

Thanks Jack and Dave. Another question. As I unbolted the old headers I noticed that coolant came out of both sides of the header/manifold bolt holes closest to the firewall. The exhast chambers are dry and the engine seams to run fine. Is this normal?

[dave-r]

Yes.

Those threaded holes go right into the water jacket.

The cast iron headers are held in place with studs so they stay in the head all the time on a standard car.

Headers use bolts so it is better to drain off some water from the engine before you take the bolts out or your feet get wet!

When putting the bolts or studs back in be sure to use sealant on the threads or they will leak.

[Johnny-D]

What other bolts on the heads and engine block go into water jackets? I ask because I am removing a number of excess bracket's off the front of my 383 big block that are not necessary for my current applications.

[dave-r]

I think the header bolts are the only ones.

[Hans]

Almost every bolt that's bolted into the front of the engine Johnny. Like the bolts that holds the bracket of the dynamo, steering pump.... And about the header bolts, I didn't knew that Dave, Thanks