Intake interchange?

I'm in the process of swapping engines in my 63' As it turns out my new engine is a 231 instead of a 225. Everything so far has been the same but I'm wanting to switch intake manifolds with the 225. Are they a direct swap? I know I could hit the Auto parts store and check part #'s but I figured someone besides me has done this before. Thanks

 

It is a 74-75 odd fire 231 with a single barrel intake. I don't have the intake # with me. Looks like a stock application to me.

 

I have an Offy 231 intake on my 225.

 

The parts man at the local FLAPS says the gaskets are different for231 and 225. The 225 is a normal gasket at about $15 and the 231 has a valley pan and runs $40-45. This may be tight of me but I'd like to figure out which gasket to use before I tear into the 231 and have to buy an expensive gasket. What have you guys used, normal or valley pan. Also, what is the real advantage to a valley pan gasket anyway?

 

I could swear I used a gasket along the runners and RTV in the valleys on my 225. It's been a while, though.

 

Use the gasket not the valley pan. The valley pan creates a heat barrier that's normally not used on any aluminum manifold anyway. The gastets are much easier to seal. Use a little RTV around the water ports to prevent coolant leaks.

 

yep, ports should be the same on the pre 78 engines -- or was it 79?

*lifts baseball cap - scratches head*

 

'79 was the first year for the "highport" head, as stated before 231/225 manifolds will swap without a problem, some ports may need capped.
A "highport" intake ('79 and up) can be used on "lowport" head if the HP gasket is used. This isn't optimal for flow but will work.

 

I went through this a few month's ago and the posts are here I presume.
Info based on 2 stock intakes.

I wanted the carb off the 231 1975 I had in a Buick Skyhawk I have and am parting out.

So I did a real nice rebuild on it and then it wouldnt fit on my stock 225 intake in my Jeepster.

Turns out its a bigger version of the 2b.

So then I got to thinking the intake off the 231 might work .

Based on the tech info here at ECJ5 I went ahead.

note I had just instaled the HEI off said motor and had to grind the 225 intake some

Took offthe 231 manifold and had it clean'd up good.

It fits just fine.
I did use the vally pan and it was fine too.
Planning on using the EGR valve too.
Just need a new temp switch for the vacume.
Havnt found one.
Note: this hole would also make a good spot for a temp sensor for an electric fan

I think this a good idea because of the larger carb and EGR does lower internal temps, and an HEI will almost just drop in.

If you look closely at the 2 pics at the right front corner bolt holeon the 2 .
The manifold on the left is ithe 225 and you can see where I grinded that down about a 1/4 inch..
The manifold on the right is the 231 and you can see it is even thinner around the bolt hole.
The 225 manifold worked as is in the pic but I could have went fruther as shown.
Nice comapison shot if you doing the HEI conversion