Any height difference?

[JMB711]

I obtained a what I thought was an almost complete stock 73 340 minus a factory intake. Pulled the valve covers yesterday to get the head #'s and found 1970 2531894 heads dated 01019 and 12268. I already have a 73 340 3671918 intake manifold, and I am wondering if its worth my while to swap that for a 3462848 1970 intake. Just for a performance standpoint?
And wondering if there is some sort of height difference between these two intakes?

 

[Xcudame]

I guess it depends on what carburetor you have or want to run. Personally, I'd use the 73 3671918 intake and build a good Thermoquad for it. But all Thermoquads are used and some are better than others.

 

[Xcudame]

Oh, any height difference is negligible.

 

[JMB711]

Oh, any height difference is negligible.

Yes, ment carb aside height difference. Would love to see some blueprints on both intakes, but I'd guess that's not happening anytime soon. Lol

 

[Chryco Psycho]

The intakes are very similar other than the different carb mounting , personally if you have a good TQ I would use that & the 73 intake

 

[JMB711]

The intakes are very similar other than the different carb mounting , personally if you have a good TQ I would use that & the 73 intake

Why the 73? I'd think the 70 would be a better match with the 1970 X heads?

 

[Chryco Psycho]

600 cfm carb or 1000 cfm carb with 73 intake

 

[JMB711]

600 cfm carb or 1000 cfm carb with 73 intake

Have no idea what TQ I have, will assume a totally stock 727. But cant do a 600 or 1000 cfm carb with the 70 intake?

 

[Chryco Psycho]

the 70 intake only has the smaller carb flange for AVS carbs , you might get a 750 AVS to work but the primary holes are smaller , Holley type carbs will work with a spacer

 

[Challenger RTA]

Just to be sure. This is not a stock flat hood, right?

 

[JMB711]

Just to be sure. This is not a stock flat hood, right?Flat hood

Flat hood. The 73 car did have the snorkel hood. Engine is installed with its Edelbrock performer intake still attached. Will install the Edelbrock 1406 carb and stock air filter housing, and do the tin foil ball trick later, but suspect there will be no real issue.

The 1406 will not work with my 73 intake. But it certainly looks like some light machining by a competent shop can open up the intake a small center amount letting the carb primaries open, avoiding a spacer? Or find a 6319 thermoquad. There is one on e-bay, looks very complete and not hacked up. Never been a real fan of aluminum intakes.

 

[Xcudame]

If Chrysler had the Thermoquad in 1968, I guarantee every 340 would have had the spreadbore intake and Thermoquad. Except or course for the 6-pack 340s, but that's a whole different animal.

I've driven Holley and Carter AFB/AVS four barrels and the Carter Thermoquad has a whole unique sound and performance. In my opinion, much better than Quadrajets and spreadbore Holleys.

I bought a 64 Imperial last year and instead of rebuilding the tires AFB, I yanked the intake off and bolted on a 73 440 intake and Thermoquad! So much better. (C and D body guys are probably pissed at me!).

 

[JMB711]

I did some poking around earlier and found that if I were to go with a 70 or 73 intake I'd need a spacer to use the Edelbrock or Holly I already have. Using the tinfoil ball method I find with the original hood pad there is just about 1/2 inch clearance. So I'm not inclined to use any kind of spacer.
As I said earlier I believe a little light machining on the 73 intake and the 1406 edelbrock will work or just find a thermoquad. Now what's nice about a thermoquad is the heat-resistant center section which is very helpful in keeping fuel temps down inside the carb hopefully preventing percolation. I also, no matter what I use, intend to block off the heat riser passage.

You are really getting me to lean towards a thermoquad. Never had one and I think it might be interesting to learn more about them. And Steve Delcich of roadkill fame also gives them the stamp of approval. lol

If Chrysler had the Thermoquad in 1968, I guarantee every 340 would have had the spreadbore intake and Thermoquad. Except or course for the 6-pack 340s, but that's a whole different animal.

I've driven Holley and Carter AFB/AVS four barrels and the Carter Thermoquad has a whole unique sound and performance. In my opinion, much better than Quadrajets and spreadbore Holleys.

I bought a 64 Imperial last year and instead of rebuilding the tires AFB, I yanked the intake off and bolted on a 73 440 intake and Thermoquad! So much better. (C and D body guys are probably pissed at me!).