340 head, intake advice please

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TA head 69?

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Recently picked up an unfinished car. 73 340, .040. 3418915 heads. Edelbrock performer intake. Aside from the obvious difference in intake manifold, head port sizes, will this seal up without any leaks? Not concerned with performance at the moment. Would like to get the car running and driving with what's here before we start dropping cash bombs. Thanks very much.

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915s are "J" heads, and came in both 1.88 and 2.02 intake valve sizes. Considered to be one of the better LA heads.
Screw it together and run it.
Of more concern is the fact that the '73 340 was a cast-crank motor; and whether your rebuild retains the cast crank. It's an adequate crank, but it is externally balanced and requires a 340 cast crank only flywheel or convertor/flexplate for proper balance. Note: this external balance is NOT the same as an LA 360 or 5.9 Magnum. generally, if it retains the cast crank/external balance, it will have a harmonic balancer like this:
1720200128891.png
1720200152639.png

If this is what it has, it MUST be assembled with the proper parts; the specific cast crank flywheel, or the 340 external balance torque convertor/or a neutral balance torque convertor and the B&M 10235 flexplate (727 trans.) which is made with the 340 external balance.
 
It does have that balancer. Haven't been under the car yet to check the flywheel. Have receipts from a machine shop for the engine and tranny rebuild. Thanks for the info! Was concerned about vacumn, oil, water leaks with the small port intake.
 
Show us pictures of the throttle bracket and kickdown linkage once you have them installed. You should have the nice Thermoquad throttle bracket-it should work on your existing carb and intake. Make sure you have the Edelbrock Chrysler throttle adapter-part number 1481. Please don't cut your original linkage up.
 
The 318/360 Performer can be port matched about an inch or so deep to a 340/360 sized gasket. Even then, it's only a few HP better than a stock '71 or '72 340 intake.
 
i'll echo what the others have said upthread and go with snapping it together and running it.

if you wanted to get saucy you could gasket match it up, but that's wholly unnecessary.

dry fit it up before laying down any gaskets and sealing goop to make sure everything fits up properly. you never know if somebody's cut the heads or intake so better to find out now than chase a leak later.
 
My 69 340 had a locator pin at the back of the block to align the intake, but my intake didn't have a corresponding hole. I just removed the pin.
 
just curious, when folks use a small port manifold on big port heads which intake gaskets do you use???
 
junkyardhero said:
dry fit it up before laying down any gaskets and sealing goop to make sure everything fits up properly. you never know if somebody's cut the heads or intake so better to find out now than chase a leak later.
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What he said! And pre lube and rotate engine over with a breaker bar while driving the oil pump with a priming tool to confirm you're getting oil to both rocker shafts.
 
Garrett Ellison said:
What he said! And pre lube and rotate engine over with a breaker bar while driving the oil pump with a priming tool to confirm you're getting oil to both rocker shafts.
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^^^ this right here.

you've got everything apart. now is the time to check, verify or change anything.
 
TA head 69? said:
It does have that balancer. Haven't been under the car yet to check the flywheel. Have receipts from a machine shop for the engine and tranny rebuild. Thanks for the info! Was concerned about vacumn, oil, water leaks with the small port intake.
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Sorry I missed the part about a 4 speed.
 
lemondana said:
Take a picture of the whole back of the flywheel. These holes in this picture are not the cast crank 340 balance holes. There should be 3 drilled circles on the middle ring on this back. I guess is this whole assembly got balanced together, it should be OK.
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No, no, no.
You're thinking of the LA 360 flywheel, which is a whole different external balance than the 340. The 360:
1720235963782.png

And the cast crank 340:
1720234916900.png

(Above diagram is also handy if drilling a standard neutral balance flywheel for the cast crank 340)

From the Mopar chassis book:
1720235334557.png

340 cast crank:
1720236421762.png
 
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Run what you got. If you have the time, equipment and skill set to open up the port window on the 318/360 performer intake, it will help a little. IMO, for a driver deal, it's not worth the time or effort.

That performer intake with a 1" open spacer works well on warmed up stuff. Open the port window/spacer and it's dang close to an Air Gap/RPM intake.

Weiand stealth and action plus have a small window and people say they are OK on a 340/360 head.
 
Garrett Ellison said:
The 318/360 Performer can be port matched about an inch or so deep to a 340/360 sized gasket. Even then, it's only a few HP better than a stock '71 or '72 340 intake.
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I found that same issue with the Performer I put on my 351W MoFoCo. Just not that much better than the iron I took off of it. Sure wasn't the Torker I put on my 289 previous to that. That 289 was an animal! :steering:
 
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