will 340 exhaust manifolds work on 318 heads?

[resq302]

The 70 challenger that dad recently got has a 318 in it bored out so it is fairly close to a 340.  The previous owner installed an Edelbrock LD340 4 bbl intake on it and has headers for the exhaust.  We are looking to get a somewhat stock appearance and were hoping that the 340 exhaust manifolds would work on this car.  Dad found a 1970 Chrysler cast iron 4 bbl intake fairly cheap and also has located a correct 340 snorkle-less air cleaner housing as well.

Can this be done and fit correctly or no?

Thanks for your answers.

Brian

[crash]

yeah the manifolds will fit.

[resq302]

Ok, so that is one vote for yes so far.  Has anyone done this to a 318 yet?  I know someone had thought that the port sizes were different but as long as it would bolt up and we would have no leaks, we can always have the openings ported if they havent been already.  I will have to go back and check out the receipts the guy gave us from having the engine work done.

[dads_69]

The manifolds will work. I have a 318 w/340 intake and H.P. exh. manifolds. Not sure which gasket they have on exh. side, 318 or 340 style. Ask the local parts store if there is a difference just in case due to port size excess that is in the way of exh.Triming gaskest might be in need. I also have a 340 w/340 H.P. manifolds also, J heads.

[Rolling_Thunder]

yes - they will worky...       had a 74 duster with them on a 318...     also seen them on a 360   

[resq302]

Just finding out now that the 68-70 340 casting numbers are different design thant he 71-74.  For those of you that have them on your car, which casting numbers or year do you have?

Thanks,

Brian

[dads_69]

I have '70 style in a '72 A body.

[Charger74SE]

Ok, so that is one vote for yes so far. Has anyone done this to a 318 yet? I know someone had thought that the port sizes were different but as long as it would bolt up and we would have no leaks, we can always have the openings ported if they havent been already. I will have to go back and check out the receipts the guy gave us from having the engine work done.

I would replace those 318 heads with 360 heads. With all the engine work done to step it up to almost a 340, the 318 heads are restricting added performance of a 4 barrel setup.
318 heads have a 1.78" intake and 1.50" exhaust valve. 360 heads have a 1.88" intake and 1.60" exhaust valve and the ports are already sized to go with the 340 intake and exhaust manifolds.
Your engine will perform alot better with the 360 head setup.

[crash]

Ok, so that is one vote for yes so far. Has anyone done this to a 318 yet? I know someone had thought that the port sizes were different but as long as it would bolt up and we would have no leaks, we can always have the openings ported if they havent been already. I will have to go back and check out the receipts the guy gave us from having the engine work done.

I would replace those 318 heads with 360 heads. With all the engine work done to step it up to almost a 340, the 318 heads are restricting added performance of a 4 barrel setup.
318 heads have a 1.78" intake and 1.50" exhaust valve. 360 heads have a 1.88" intake and 1.60" exhaust valve and the ports are already sized to go with the 340 intake and exhaust manifolds.
Your engine will perform alot better with the 360 head setup.

i agree, 360 heads will wake up a 318, or if you could find some 2.02 valve  340 heads.......... 

[resq302]

I am assuming that the heads are correct numbers/dated matching as everything we got with the car was original to the car with the exception of the modded stuff he put on that was still on the engine. Everything that was original to the car came with the car in the trunk.  I guess when I have to pull the valve covers I will find out if it is the correct casting number and date and such.  I do know from the engine building receipt and blue print, that the engine was ported and polished so it might be ported out to match up to a 340 exhaust already.  All I do know is that the car can perform a hell of a lot better than my 383 HP engine with my 4 spd.  I am trying to convince myself that it is a whole power to weight ratio thing since the chally is so much smaller and probably lighter than my charger.