273 v8 intake question..

[crashcaptn]

I have a 1965 dart GT with a 273/904 and i wanted to know if the intake manifold for a 318 would fit and work on my engine? I have the stock 4 barrel intake on the car currently with a holly 4 barrel, but would like to switch to something a bit more powerful and i can only find intakes for 318 and on. I do know the small blocks were somewhat interchangeable, but i didn't know to what degree. Any suggestions?

[cudajim]

I have interchanged them with no problems whatsoever.

I do have an original 273 intake manifold, it's heavier than hell though.

[cudajim]

I see you're in Northern California - what town?

I currently own 2 barracudas, a 69 fastback/318 and a 67 ragtop/273

[crashcaptn]

Hey there, I'm in Rohnert Park, next to Sonoma State University. There isnt much of a scene up in this area so i get a lot of questions about "wow, what IS that??"

[1 Bad Mirada]

i thought that all of the production small blocks from the last 40 or so years (nono magnum) were interchanglable with respect to the components. (obviously not the rotating assembly, at least not without some machining)

[crashcaptn]

Not completely. What ive learned is the small block 273 has a strange angle for the intake manifold. You actually have to get one for the early model. The 318-340 and so on has a different angle. The transmissions are a bitch too in 1965!

[440roadrunner]

My memory is getting old, but I don't think the angle you speak of is the same for all 273's--that is I think later 273's were the same angle as the larger LA engines, HOWEVER--

I'm not sure you'd gain anything by using a 318 intake on your 273, anyway. The 318 ports may not match up very well.

(I once put 273 heads/intake on a 360. What a torque hound, up to about 4600RPM--at which time you might as well get out and push!!)

[lonewolf6108]

what ive been told is that the intake runners on the bigger small blocks are larger than the 273. they will bolt up, but you wont get much better flow, because the runners on the intake will be a different sise and shape than the head. but i have been told that 318 stuff works pretty well on the 273. also ive also been told that there are differences in the pre 1967 273's that restrict the number of parts that interchange. BUT none of this is first hand info, when i get ready to but an intake and four barrel on my 273 ill call mopar performance or offenhauser. i know through summit that offenhauser makes an aluminum intake that says right in the discription that it will work for the 273, but they want something like 250 bucks for it!

[Mopar Guy in Delaware]

I think even if you can get an intake to fit, the best situation would be to port and polish the combination and resize the gaskets as needed.

Also matching the carburetor to the intake will produce a much smoother flow thru the engine.

If you go that far, it would be well worth the effort to plan in the future when the heads are off. To decarbon the cylinders, pistons heads, valve guides & stems and cc the heads.

The next step would be to do the same for the exhaust head ports and manifolds. If you going for headers. The length from the carb throttle plate to the valve seat should be roughly 2/3 the distance from the exhaust valve seat to the end of the header collector or cutout opening for max flow and peformance.

Again the engine is noting more than a air pump with internal controlled explosions. The unobstructed cfm's of air in will combine with the best fuel amount for the best fuel air mixture and an explosion within the combustion cahmber producing the most btu.
I'm talking max power here.