Manifold help

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MechArm1

MechArm1

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I have a 318, I just took the old stock manifold off because I had a torker 340 manifold to put on. well It doesn't seem to fit. will that manifold only work with 340 heads on the 318?

Also it has a small dowel on the engine block that the old manifold has a hole for. And at each corner there are these little tiny tabs that are sticking out? they are very thin easily bent little things, two each at all for corners. Are those part of the head gasket? Do I leave tose when instaling the new manifold?

If I'm limited to only a manifold that fits 318 heads to add a 4 barrel, what manifold should i be looking for?

Any help on the things I pointed out would be great. . the car was running this afternoon, and now its sitting with no hope of starting up till i figure something out.

I Have AC and want to keep that, if that helps the suggestions for certain manifold.

Thanks for any help
 
273-318 intake ports are smaller than a 340-360, the tabbies are for the intake gaskets at each end of the engine to hold them into place. make sure you use a .60 gasket set for aftermarket intakes . the dowels are locators for the intake. you need one for a 273-318 , edelbrock, weind etc. make good intakes for the SB LA engines. i think it will physically will bolt up and work, but i have never tried.
 
you could pull the locator pins out and the manifold will fit, may not be ideal as mentioned above, but it should work
 
I would use a manifold made for the 273/318 port size. They just flow better. Most brands have a street version that has the bosses for the A/C brackets. If this is a street car with freeway gears, I would get a dual plane for better low end torque. If this is for high revving performance use, get a single plane. Use the locating pins if the manifold has the holes or pull them out if it doesn't.
 
Thanks for that info guys. So that manifold "should" physically fit on there? even if the port size is too big. I felt like it was too "wide" to sit down in there properly, like it was just the wrong manifold. It didn't seem like the dowel was the factor keeping it from fitting, If I pull the dowel out just to see if that was possibly the difference, will it hurt anything to not have the dowel on there, if i put the stock manifold back?

Thanks also for the info on the little tabs and the dowel,

If I could find a really good deal on a 273/318 manifold i might get one, but this manifold was a freebie, and should only be on there till i get a set of heads and a few other items i need to put the 340 in it. . .

Thanks for the replies
 
The dowels are for alignment of the manifold and gasket. If you're carefull setting the manifold on, there should be no problem. Don't be surprised if you have a bad hesitation using that manifold on those heads. Other than that, it will physically bolt on.
 
Actually the dowels are used for port alignment.

Turn the intake upside down. Take a straight edge and run it up the center of each port separator . Scribe a line around the top of the intake, Now you can physically see the center of the divider of the ports from the top looking down.

On the head itself the center is defined by the valve cover bolt. It is in the center of the port divider.

Set the intake on the engine with the dowels in place. Put the scribed lines in the center of the holes for the valve cover bolt holes . Now you just aligned your new intake to your heads. Tap down on the intake so the dowels leave a mark in the underside. Center punch them and drill them 1/4 to 3/8 deep. Now every time you install the intake you know for sure it is in the center of the port separators. Alot of guys take them out because they think they are for only holding the center of the end gaskets

Your intake probably don't fit. Meaning you are having a hard time getting the bolts started. Early heads pre 70 are different. Did any one try and put a 70 six pack on a x head motor. Now I am talking un cut heads or block. You probably will find it hard to get the bolts started also. A LD 340 intake will fit on a x head motor. Try and install a later intake and you will run into this problem. All later intakes are Machined for uncut 915 castings an newer with a 956 deck. All 340's with X / 894 heads were listed as 10.5-1 all later 340's with U,Z / 915 heads were 10.3-1. they didn't change the deck or the pistons in 70,71 it was the heads that were cut more in 69 back. This is the reason later intakes are tough to get on early motors. Today they make different thickness gaskets to help the installation,. And also its hard to find a block or heads that were not milled. Use this info however you want. Its what I found from building these motors for years. X heads were always known to be the head of choice. It was the increased compression that made them better . The castings were identical to the 915's it was the machining that made them perform better.
 
Thanks again, I'll be looking for a manifold more suited for the car, maybe i'll get lucky and find something that's for a 273/318 for cheap.

Thanks
 
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