340 Intake

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bobscuda67

bobscuda67

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I'm putting together a 340\373 cube motor with iron magnum heads and 69 340 exhaust manifolds and was thinking of a iron 340 intake and a thermoquad carb. Is the performance level of this intake combo good enough to get me to high twelves with good traction? Or should I go to a aluminum intake with a Holley? I like the factory look of the iron intake, plus it has the mounting bosses for my a\c compresser. Thanks in advance, Bob
 
bobscuda67 said:
I'm putting together a 340\373 cube motor with iron magnum heads and 69 340 exhaust manifolds and was thinking of a iron 340 intake and a thermoquad carb. Is the performance level of this intake combo good enough to get me to high twelves with good traction? Or should I go to a aluminum intake with a Holley? I like the factory look of the iron intake, plus it has the mounting bosses for my a\c compresser. Thanks in advance, Bob
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cant realy answer your question but i hope you know that the intakebolts are at a diferent angle on magnum heads unless you have a set of those new moparperformance magnum heads with oldstyle intake bolts
but its not imposible to redrill and tap the boltholes
 
You will easily be able to run high 12's with that intake and carb. There is a stock eliminator 340 duster that runs at the track I run at that runs high 11's with the iron intake and TQ.


Chuck
 
I also agree, the stock cast iron T-Q intake and carb are up to task for 12's. You may not even need to cam it up veru much. Combo dependent of course.
(I'm not a fan of exhaust manifolds myself.)
 
I found a Offenhauser Dual Port intake on e-bag for a thermoquad and was wondering if those are better than a stock cast iron intake, other than the weight savings. Bob
 
I have never used an Offy dual port intake but have seen tests on them and some people run them and in some cases they performed worse that a stock 4 barrel intake. If you were going from a 2 barrel to that intake then yes you would have a gain in performance.
If it was me I would use the stock intake over the Offy.

Chuck
 
bobscuda67 said:
I found a Offenhauser Dual Port intake on e-bag for a thermoquad and was wondering if those are better than a stock cast iron intake, other than the weight savings. Bob
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Do not touch that intake!!!!!!!
 
Thats the felling I'm getting from people I've talk to. I'll think I'll stick to my original plan. I found the Demonsizzler website and their thermoquads look pretty nice. Anybody use one? Is their a better year cast intake to look for. I noticed some of them have egr's and balance tubes in the secondarys. I assume an earlier intake would be better. Bob
 
bobscuda67 said:
I found a Offenhauser Dual Port intake on e-bag for a thermoquad and was wondering if those are better than a stock cast iron intake, other than the weight savings. Bob
Click to expand...

I had a couple of friends who used Offy Dual-Port intakes. One was on a 318 Challenger with a Thermoquad & the other was on an Olds Cutlass 350 with a Quadrajet. I wasn't very impressed with the way either of them worked.
 
bobscuda67 said:
Thats the felling I'm getting from people I've talk to. I'll think I'll stick to my original plan. I found the Demonsizzler website and their thermoquads look pretty nice. Anybody use one? Is their a better year cast intake to look for. I noticed some of them have egr's and balance tubes in the secondarys. I assume an earlier intake would be better. Bob
Click to expand...

I have used Demon sizzler before. NIce results. You'll enjoy it.

I have no idea what a balance tube is. The EGR's can be blocked off. Actually, just mount the valve and fail to hook it up. It opens with vacuum, closes when you hit the hammer.
The floor jets can be pluged on one side and welded shut on the other. Or drilled and tapped then pluged.

The earlier years do not have the EGR valve in them and that would be a plus in time at the shop for sealing up the floor jets.
 
Oh, the balance tube you mentioned equals the EGR path ways under the intakes runners....IIIIII got it now.

There was just an early T-Q intake on E-bay the other day. There heavy, so keep that in mind when calculating shipping.
 
1971 was first year for TQ and the TQ intake. '71 and '72 are IMHO the best years for the TQ cast intake. The later years had the 'bolt' in the plenum floors. Removing that and pluging with JB weld or welding it closed then it would be equal. Have to know what you are doing to weld cast iron..be careful. Good luck and as always...give us a progress report. Terry.
 
Thanks guys, looks I'll be looking for a 71 or 72 cast intake.
Bob

Car parts 008.jpg
 
Thanks Adam, I found it. Its a 72 and it looks nice, and its located about 30 miles away! Bob
 
hi, the last four casting numbers are 2100, this is the 71-72 T.Q. manifold, it has no egr in the floor. the last numbers of the replacement manifold is 025,
this will have small casting humps in floor, bit no holes.
 
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