Magnum Manifolds - New plan

[YYZ]

FWIW the upswept (driver's side) 340 manifold is the easier one to find of the pair as they were used on '71 A-body 340 cars. 

Flow, IIRC is very similar between the late Magnum manifolds (360 in particular) and the '68-'70 340 ones, so you wouldn't have a big mismatch from side to side.

Post up on Kijiji and get ready to hit the first Ancaster meet?

[Cudajason]

@anlauto Allan, do you have any pics of the non HP 340 manifolds on an assembled engine / k frame, that you could share?

Thanks,

Jason

[anlauto]

@Cudajason  What is a "non HP 340 manifold" ?

Not sure if I have pictures of what you want, BUT....here is a 1971 340 with the correct 71 manifolds.....

[RUNCHARGER]

Jeez: I didn't realize that 71 340 E-bodies used both the "junk" log manifolds. Yet the 71 340 is the best one due to the TQ. I wish I had known that when I was building sleepers back in the 70's.

[GY3R/T]

Beleive it or not.. There's not a lot of difference in flow between  68-70 HP's and 71 logs.

[Cudajason]

Thanks @anlauto ....that is exactly what I was looking for. 

I am guessing the casting numbers on those manifolds are:

pass - 3418623
driver - 3418621

These seems to be lots of space between the manifolds and steering box. 

For a guy like me, whose focus is not so much on the power, this look like the ticket!

Jason

[Cudajason]

Ok new plan!!!

I picked up these up today off of Kijiji!

Casting numbers are:

pass - 3418623
driver - 3418621

Which are for 71-73 340.

They need a little bit of work on the heat riser, but they will work!

Any suggestions on the heat riser, I have no interest in rebuilding it ($300 for the kit!!!)

Jason

[Topcat]

Looking good Jason.

Can't wait to hear my previous mufflers and resonators roar to life once again.

[RUNCHARGER]

The heat riser isn't really necessary on a hobby car IMO. If the shaft is not there you can just run a bolt across with a nut to seal the holes up.

[Chryco Psycho]

Or tap the holes with a pipe tap & insert plugs

[Cudajason]

Looking good Jason.

Can't wait to hear my previous mufflers and resonators roar to life once again.

Yeah me too!  been a long time coming.

Or tap the holes with a pipe tap & insert plugs

It looks like that is what some one did...but not well.  I will likely drill out what's there and try that.

Jason

[RUNCHARGER]

Don't wrench them in too tight and crack the casting.

[jimynick]

Don't wrench them in too tight and crack the casting.

Yep, couldn't you use brass plugs? You'll not likely get it hot enough to pose a problem with them. Kenny over at Brant Performance in Brantford has a set of the upswept manifolds laying on a shelf. I saw them the other day and forgot to ask him what he'd take for them, should you be interested. As for the heat riser, is the original shaft still there Jason? If it is, we can get it loosened for you. Let me know if that's something we could help with, eh? 

[Cudajason]

Don't wrench them in too tight and crack the casting.

Yep, couldn't you use brass plugs? You'll not likely get it hot enough to pose a problem with them. Kenny over at Brant Performance in Brantford has a set of the upswept manifolds laying on a shelf. I saw them the other day and forgot to ask him what he'd take for them, should you be interested. As for the heat riser, is the original shaft still there Jason? If it is, we can get it loosened for you. Let me know if that's something we could help with, eh? 

Thanks for the offer Ian @jimynick   I think I am good with what I have. 

No heat riser shaft left in the manifolds.  I will likely try go with the brass plugs.  Looks like there are sleeves in the manifold that have already been tapped.  I will drill them out and tap them.

Don't worry I will post pics as I go!!!

I think I will hit up Accurate next week for some head pipes and maybe over the axle pipes. 

Jason

[PLUM72]

Looks good.  How much more clearance do you have with the old 340 manifolds over the magnum manifolds?  I saw the pictures but looking for an dimensional estimate.  I think you barely had an 1/8 inch with the magnums.