273 Ex Manifold on 360 Head? Will it Work?

Hi--will a 65 273 exhaust manifold seal and work on a std 340 / 360 head like a J head?? I know bolt pattern is same just wondered if it will cover the port and seal--Thanks!!

The overlap between the outer portion of the head's exhaust port and the manifold will be very very narrow. You will need to pay close attention.

I think I had like 1/8" overlap on my 65 Cuda with the 273 manifolds. Mock it up on the stand and you will see.

what Supercuda said & I forget if you want the 273 or the regular 318/360 gaskets, the ones that are whiteish on one side and silvery with indentations on the other side I forget the brand (or make your own)

I have some 273 manifolds on a 78 360. I had to plug the smog/emission ports but they sealed up fine with the silvery gaskets in the Fel Pro gasket kit.

No, I had one customer do that exact same thing using OEM 1965 273 exhaust manifolds on a 340 motor with J heads in his 1965 cuda fastback, it was a real turd through those manifolds Measure the height and width and go from there Maybe the Hi Po 4 barrel 273 mnifolds might, might have enough meat in them to allow opening(porting) them up big enough to work on the later heads
Let us know what you find out and do

I was thinking the same thing. Can? - Probably will physically fit with no leaks. Should? - Probably not, due to being flow restricted. I'd at least roll the port openings back with a carbide cutter to the exhaust port actual size (NOT header gasket size).

My 2 cents is that this would definitely be either a no funds to buy other manifolds situation, or a fitment issue situation - just not a good idea if you can get the 360 manifolds that will fit the body.

I don't see why it wouldn't seal, but your giving up alot of hp, if you have the extra cash get a set of tti headers, not sure if 340 or 360 manifolds will fit but if you don't have the cash for headers you might want to look into it.

yes, the outlets on them are 1&7/8" which is the same as (1) big block header primary tube dia. On an early A they are a good fit for a low po DD

The low po 273 2bbl and hi po 273 4bbl used the same exact exhaust manifolds.

The only direct dyno test I seen showed all the small block manifolds within about 10 hp on a 300 HP magnum crate engine. Everything from the 273 tiny ports to the early 340 "pot o gold" manifolds. I know my old 66 dart when I started off had the factory 273 manifolds and switching to 340 manifolds did not show up in the time slip but it was a stock 360 at the time(talk about a huge let down after hearing all the hype and coughing up $500), maybe a big built stroker or something would show more difference. Even the FAST guys all seem to be in agreement that extrude honing is pointless also. I think if you are running manifolds run what you brung and don't worry about it.

Here you go

http://www.hotrod.com/how-to/engine/mopp-0307-mopar-crate-engine-exhaust/#photo-18

Note the 318 manifold they used is the same as a 273 manifold

I am just asking about physical--will it bolt up and seal without grinding heads etc--power robbing not the issue--Thanks again!!

mine sealed fine once i permanantly plugged the smog holes

My car ran hot when going threw the manifolds switched back to headers and it was fine Performance was way off also

Thanks everyone!!!

as said with the right gaskets/plugging the smog holes it will seal, You know us we're always going off on a tangent, we call it covering all bases!

Hi all, does anybody know the correct format and spacing for the 2 emblems that go on the tail panel of a cuda?

[]Just a slight hijack of a post, hahaha.

R.[]

dont get on much, not too sure how to post. my apologies

Go to the restoration forum and click on the upper left hand side under new subject and ask your question on there, hopefully someone who knows about that will respond

Thank you