1972 340 testing by Nick

[1971 CY Dodge Dart]

This was a pretty good episode. Nick took a stock 1972 340 and did a mild build on it. Stock was 8.5:1 compression and now it has 9.8:1. Some mild porting of the stock heads and intake valves are now 2.02 vs the stock 1.88. Stock cast iron intake, stock thermoquad carburetor.

Unfortunately the owner didn’t give Nick the specs on the flat tappet cam.

Hooker Super Competition headers made only 16 horsepower 22 lb feet of torque over the restrictive 72 manifolds.

 

[fishmens67]

Hooker Super Competition headers made only 16 horsepower 22 lb feet of torque over the restrictive 72 manifolds.

I think 16 hp and 22 ft lbs is a nice gain, nothing to sneeze at, the headers also opens it up for further modifications.

 

[fishmens67]

Oh and ode to the mighty 340. lol
The 360's little brother.

 

[1971 CY Dodge Dart]

I think 16 hp and 22 ft lbs is a nice gain, nothing to sneeze at, the headers also opens it up for further modifications.

No question if the motor was going to be built for more power the headers would be more beneficial. In this case though the owner isn’t going any further with the engine.

16 horsepower and 22 lb ft of torque is probably in that grey area. Some will say headers are worth it and others are going to see it differently.

 

[fishmens67]

The fact is headers are the best bolt-on to improve performance.

 

[273]

The fact is headers are the best bolt-on to improve performance.

And 4bbl if the car doesn't have one of them are basically pure gains with basically no down sides performance wise, and cr also most other mods generally have some performance compromises.

 

[a-bodyguy]

The fact is headers are the best bolt-on to improve performance.

spray is the best bolt on its not even close

 

[Slantsix64]

Headers baby!!!!

 

[Bodyperson]

Like I've said before. Stick that 340 in an A-body with stock manifolds and exhaust pipes that need to clear torsion bars and the center link and see how much hp loss there is.

 

[a-bodyguy]

Like I've said before. Stick that 340 in an A-body with stock manifolds and exhaust pipes that need to clear torsion bars and the center link and see how much hp loss there is.

And they runs 10s and 11s just like that

 

[Bodyperson]

And they runs 10s and 11s just like that

No doubt but that doesn't answer my appeal to know the difference between that and the relatively free flowing exhaust on Nicks dyno.

 

[a-bodyguy]

No doubt but that doesn't answer my appeal to know the difference between that and the relatively free flowing exhaust on Nicks dyno.

Its been done before its about the same or less
nick just did a 390 stroker with exhaust manifolds 525 lift cam
over 400 hp 440 torque

 

[496 polara]

I will take 16hp and 22tq every day of the week. And that is just peak. I would imagine gains would be larger in most cases across the curve and hold on longer after peak as well.

 

[a-bodyguy]

I will take 16hp and 22tq every day of the week. And that is just peak. I would imagine gains would be larger in most cases across the curve and hold on longer after peak as well.

On a stock motor its less
that test used the chit straight dump 318 type maifold
15 hp for 1k bucks for tti headers is not a great to me
900 bucks for spray 125 hp and 200 lb ft of torque sounds better its also on demand
Ive had headers on every sbm except this last 340
if you can run 11s with manifolds then pop the hood no headers the chebbie and ford guys can sulk something about that i like

 

[CFD244]

Would have been a neat manifold comparison with the 68-70 HP's. It would be nice to see if the hyp is real.

 

[Topless69]

I remember watching this episode and thinking 30 over, 2.02 valves, 9.8cr, head porting, mystery cam, this build isn’t close to stock, and if Nick is getting 65hp/50tq over 72-73 factory specs. with manifolds nobody should be surprised. If I was going to do the same thing, I’d be looking to get over 400hp/tq

 

[fishmens67]

spray is the best bolt on its not even close

yea I've seen allot of blown motors in the late 70's/ 80's when nitrous entered the street scene. not exactly a bolt-on and go.

 

[340sFastback]

Like I've said before. Stick that 340 in an A-body with stock manifolds and exhaust pipes that need to clear torsion bars and the center link and see how much hp loss there is.

TTI makes mandrel bent head pipes for the 340 manifolds that are a full 2 1/2 inches no pinches or dents and they clear everything just fine.

 

[1971 CY Dodge Dart]

TTI makes mandrel bent head pipes for the 340 manifolds that are a full 2 1/2 inches no pinches or dents and they clear everything just fine.

Yep, that’s what I have.

 

[a-bodyguy]

Would have been a neat manifold comparison with the 68-70 HP's. It would be nice to see if the hyp is real.

its already been done
the holy grail manifolds were 3 or 4 better then the other manifolds
that dropped the gain to 10 to 12 hp 15 lb ft torque

 

[273]

I remember watching this episode and thinking 30 over, 2.02 valves, 9.8cr, head porting, mystery cam, this build isn’t close to stock, and if Nick is getting 65hp/50tq over 72-73 factory specs. with manifolds nobody should be surprised. If I was going to do the same thing, I’d be looking to get over 400hp/tq

The cr and valves puts it more in line with the older 340, be nice to know the cam specs.

 

[Topless69]

The cr and valves puts it more in line with the older 340, be nice to know the cam specs.

Yep, The description for this motor reads like an early 340, except for the porting and mystery cam

 

[a-bodyguy]

It had about the same vacuum at idle as my comp 268 its not a big cam
iam at 9.9 to 1 that motor is close to mine imo
my bottom end has 100k but has great cranking psi
320 hp good stockish 340

 

[65 Cuda 340]

I'm not sure where +16 comes from. I see a peak hp with manifolds of 328 at 5200, and 349 at 5000 with headers (see dyno sheets at 15:09 and 30.40). That's a 21 peak hp gain. But the gains are throughout the rpm range, not just at peak.

Here's what I see headers being worth over the manifolds, according to Nick's dyno:

3000 rpm +6

3500 rpm +13

4000 rpm +21

4500 rpm +16

5000 rpm +29

5200 rpm +20

As for my own experience, I replaced the stock manifolds on my old otherwise stock 73 Duster 340 with cheap BlackJack headers, and replaced the 68-70 340 manifolds on the mildly modified 340 in my 65 Barracuda and the mildly modified 360 in my 67 Barracuda coupe with TTI. In all cases, the power difference was amazing, at all speeds, low to high. Makes me wonder about the small gain at 3K on Nick's dyno. But ???

I don't have a problem with anyone who keeps his manifolds - I did for a long time, because in the old days, headers leaked, rattled, had to be clearanced with a BFH, and the A body ones hung so low that two tubes got flattened (my stepson knocked a hole in his in less than two weeks; I never beat mine that badly in two years of daily driving, but they did get flattened). The ones I put on my Dad's 440 had so little plug wire clearance that we routinely shorted out two plug wires - a problem we almost fixed with Hemi spark plug wire ceramic insulators.

Manifolds were much quieter, fit better, were more durable, and still made decent power for a street cruiser.

But there are good headers today that fit, don't leak and don't hang low. There's really no downside to running them except for the cost (and I sold the 68-70 manifolds in my two Barracudas for enough to pay for TTI headers).

 

[a-bodyguy]

I'm not sure where +16 comes from. I see a peak hp with manifolds of 328 at 5200, and 349 at 5000 with headers (see dyno sheets at 15:09 and 30.40). That's a 21 peak hp gain. But the gains are throughout the rpm range, not just at peak.

Here's what I see headers being worth over the manifolds, according to Nick's dyno:

3000 rpm +6

3500 rpm +13

4000 rpm +21

4500 rpm +16

5000 rpm +29

5200 rpm +20

As for my own experience, I replaced the stock manifolds on my old otherwise stock 73 Duster 340 with cheap BlackJack headers, and replaced the 68-70 340 manifolds on the mildly modified 340 in my 65 Barracuda and the mildly modified 360 in my 67 Barracuda coupe with TTI. In all cases, the power difference was amazing, at all speeds, low to high. Makes me wonder about the small gain at 3K on Nick's dyno. But ???

I don't have a problem with anyone who keeps his manifolds - I did for a long time, because in the old days, headers leaked, rattled, had to be clearanced with a BFH, and the A body ones hung so low that two tubes got flattened (my stepson knocked a hole in his in less than two weeks; I never beat mine that badly in two years of daily driving, but they did get flattened). The ones I put on my Dad's 440 had so little plug wire clearance that we routinely shorted out two plug wires - a problem we almost fixed with Hemi spark plug wire ceramic insulators.

Manifolds were much quieter, fit better, were more durable, and still made decent power for a street cruiser.

But there are good headers today that fit, don't leak and don't hang low. There's really no downside to running them except for the cost (and I sold the 68-70 manifolds in my two Barracudas for enough to pay for TTI headers).

It made 341.3 and climbing still @5700 with manifolds
with the chit 72 manifolds