LA 340 Intake Manifold

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Yep, your engine sounds like a hot rod piece. Overbuilt for most street cruisin'. Pull it and sell it. Like mentioned, a Magnum is a goid choice.
Yeah it was a hot rod no doubt. It runs just not optimally of course and the converter is un matched. I hear ya about the Magnum swap. I also have the or318 but that needs to be gone through as well and may require machine work.

How does one find a decent magnum motor? Salvage yards suck here in phoenix. Do they furnish cherry pickers? I don’t have a truck or anyone to help me so thats a problem right there…
 
Was wondering can you stack head gaskets? Or is that unreliable? Never heard of it being done before.
Heard of it being done, but they won't seal worth a sh**.
Heck, Direct Connection used to sell head spacers to drop your compression, back in the bad old days of the first couple of "gas crises". Didn't last worth a hoot then, they dropped them pretty quick.
Plus, once you start stacking, or using spacers, or whatever- you start messing up your intake port alignment, so you have to stack intake gaskets to compensate, and it just snowballs to the point where nothing fits right and everything leaks...
 
How does one find a decent magnum motor? Salvage yards suck here in phoenix.
Keep your eye on FakeBook Marketplace and Cracklist- not just for the motor itself, but for entire vehicles (trucks, vans, Durangos, Jeep GCs, etc.) that might have a blown transmission, have been hit, are rusted beyond saving (well, maybe not in Phoenix...), and can sometime be picked up whole cheaper than just the engine can be found elsewhere. Take what you need, part out the rest, scrap the carcass, and you might just break even or even turn a slight profit on the whole deal.
 
So is this design considered a square bore and compatible with my Holley double pumper 4150? Is this because the port is equal shaped as opposed to a larger secondary and smaller primary?

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For the LA motor do I need to drain the radiator coolant prior to replacing the intake manifold?

Sorry so many many questions here. But really appreciate the help here!
 
You can get a good chunk of $$$ for that M1 intake if you don’t price it too low, no need to under price, I bet you could sell it here quite easily, especially if it’s unmodified or undamaged. You may find a good used Edelbrock RPM or Air Gap if you keep your eyes peeled. Might end up being an even swap. Doesn’t look like you’re pressed for time so take some time and look around.
 
I’ll have to get back to you on the specs as I don’t have this Info handy right now. Was wondering can you stack head gaskets? Or is that unreliable? Never heard of it being done before.
Stacking head gaskets? I’ve never done that. What I did do a long was back was use the MP head shim to drop the compression down. It is a .060 thick steel shim you use with a gasket on top. You could use one on both side of you wanted to. I did not. What it did for me was drop the ratio from over a 10-1 engine requiring 93 to an engine that used 87 quite well.

I doubt you’ll find the MP head shim anymore. Now, I just call Cometic and spec what I want and they make it up. What Cometic does is use thin steel to make there gaskets and stack them up for the desired thickness. I have used them several times without issue. As thick as .100 thick, no problem.
Cometic rivets them together. The rivets are outside of the contact area of the block and heads. Nothing special needed for there use.
 
Stacking head gaskets? I’ve never done that. What I did do a long was back was use the MP head shim to drop the compression down. It is a .060 thick steel shim you use with a gasket on top. You could use one on both side of you wanted to. I did not. What it did for me was drop the ratio from over a 10-1 engine requiring 93 to an engine that used 87 quite well.

I doubt you’ll find the MP head shim anymore. Now, I just call Cometic and spec what I want and they make it up. What Cometic does is use thin steel to make there gaskets and stack them up for the desired thickness. I have used them several times without issue. As thick as .100 thick, no problem.
Cometic rivets them together. The rivets are outside of the contact area of the block and heads. Nothing special needed for there use.
So in pulling the intake manifold do I need to drain the radiator coolant?
 
Ok keeping you guys busy must be my thing today. What is the smaller line from the water pump to the manifold? Is this a return path or bypass? And why do I not see this on the Chinesium manifold ?

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I would finish the car, and at least drive it with what you already have, then make a decision on which way to go.
 
I would finish the car, and at least drive it with what you already have, then make a decision on which way to go.
Yeah I hear ya but the issue is to fit the hood I needed to remove the carb spacer and subsequently lost my pcv vacuum port. I don’t want to drill out the race manifold for that. Seems like I can pop in a more appropriate manifold and have one that supplies my pcv and works better for the road. It might even be 1/2 shorter which I’ll take as well.
But point taken and thats my plan I have a ton of work to do in assembly beyond a simple manifold swap right now.
 
So in pulling the intake manifold do I need to drain the radiator coolant?
I’m surprised to read this. This is a basic thing most know already. Have you worked on any small blocks at all? Big blocks?
I think you need to read a few books. We can’t teach you a step by step of you don’t know the basics to these engines. A “How to rebuild” book should be a must have book n your library.

There are two plugged water ports in the block on each side of the engine. I suggest you pull these out as to drain the water from the heads down to empty the heads best. Emptying the radiator doesn’t get to the heads and such fully. Even tilting the engine helps. The intake also holds some coolent. Tilting the engine a slight bit (via a jack) helps get it all. After all, the less coolant in the oil pan the better.
Ok keeping you guys busy must be my thing today.
:rofl:

:thumbsup:
What is the smaller line from the water pump to the manifold? Is this a return path or bypass? And why do I not see this on the Chinesium manifold ?

View attachment 1716116850

View attachment 1716116851
The top picture is a newer intake that has the water by pass nipple like a Magnum engine.
 
I’m surprised to read this. This is a basic thing most know already. Have you worked on any small blocks at all? Big blocks?

It’s 118F here my brain is short-circuiting lol. I’ve done it once before. This is a virtual garage hang out for me as I don’t have any family close to me, none of my neighbors work on their cars heck l never even see them cut their lawns or paint there houses lol. Most of my friends are out of state and so I am grateful to be able to bounce my questions off you guys as if we are all hanging out in my garage shooting **** talking **** drinking beer and wrenching on a car together.



I think you need to read a few books. We can’t teach you a step by step of you don’t know the basics to these engines. A “How to rebuild” book should be a must have book n your library.

There are two plugged water ports in the block on each side of the engine. I suggest you pull these out as to drain the water from the heads down to empty the heads best. Emptying the radiator doesn’t get to the heads and such fully. Even tilting the engine helps. The intake also holds some coolent. Tilting the engine a slight bit (via a jack) helps get it all. After all, the less coolant in the oil pan the better.

:rofl:

:thumbsup:

The top picture is a newer intake that has the water by pass nipple like a Magnum engine.
 
It’s 118F here my brain is short-circuiting lol. I’ve done it once before. This is a virtual garage hang out for me as I don’t have any family close to me, none of my neighbors work on their cars heck l never even see them cut their lawns or paint there houses lol. Most of my friends are out of state and so I am grateful to be able to bounce my questions off you guys as if we are all hanging out in my garage shooting **** talking **** drinking beer and wrenching on a car together.
Trust me, most happy to answer them and help you along with the project. Keep asking questions! Don’t be shy!
 
Yup it’s really slowing me down getting work done. The low here in Phoenix was 90F!

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I am to old for that heat anymore, good luck getting anything done.
 
Question about the M-1 intake, as I have a new one, that has never been run, on a bagged 340 in my Garage. did these (M-1) ever come in a dual plane,??.

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M1 was the name of a line of manifolds sold by MP- there were single plane, dual plane, big block, small block, Magnum, carb & EFI manifolds...
 
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