340 Head/Cam upgrade before vs after with results

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IQ52 said:
Most welcome, love following your stuff. Especially with the iron heads. We don't get to build the short block but I'm waiting to see what this small block 340/440ci with ported stock 340 iron intake, ported 596 heads with 11/32 x 2.02 intakes flowing 278 @ .500" and a custom solid flat tappet. It is a undercover stock look even using stock 340 cast iron exhaust manifolds.
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Well we know it will make tons of torque! Is this for a F.A.S.T. car? Or is this someone's sick idea of a sleeper--lol! That will be interesting for sure. J.Rob
 
RAMM said:
Well we know it will make tons of torque! Is this for a F.A.S.T. car? Or is this someone's sick idea of a sleeper--lol! That will be interesting for sure. J.Rob
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I get the idea it is for a street car that may someday see the track once. I think the little Abody, with a trunk full of concrete for traction, may be able to upright overturned semi tractor-trailers.
 
My comment was totally a joke. I run 2.05 intakes all the time... with the right bowl prep and valve
Job. RAMM is one of very few guys I would pay to do stuff for me if he were close. I also enjoy his tests mostly for the reality they present.
 
moper said:
My comment was totally a joke. I run 2.05 intakes all the time... with the right bowl prep and valve
Job. RAMM is one of very few guys I would pay to do stuff for me if he were close. I also enjoy his tests mostly for the reality they present.
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Anybody who saw the "lol" should have immediately recognized it as a 'tongue-in-cheek" comment.
 
moper said:
My comment was totally a joke. I run 2.05 intakes all the time... with the right bowl prep and valve
Job. RAMM is one of very few guys I would pay to do stuff for me if he were close. I also enjoy his tests mostly for the reality they present.
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That's quite the endorsement! I appreciate your comments directed at realistic testing and builds Thankyou, and I figured you were being facetious with the 1.88" statement. J.Rob
 
You know something I realized that would have made the after testing look a little better is the water pump arrangement. I swore I used this belt and pulley arrangement the first time but the picture shows an electric set-up. This would have yielded an additional 5-7 hp had I gone this way. Oh well. J.Rob
 
Great post, thanks for taking the time to share your knowledge. Have you ever considered moving to Florida.
 
mderoy340 said:
Great post, thanks for taking the time to share your knowledge. Have you ever considered moving to Florida.
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Your welcome and no offense but I hate humidity, you'd be surprised how humid it gets here in the summer months. J.Rob
 
That's true! The humidity does creep up north. I myself, living on an island can not escape the steamy water in the late summer. It becomes murderous here late July & August.

Also true.....

Real actual tests with real world builds. No guessing. Bamm! There it is, just the facts.

J.Robb, what do you figure the
RPM intake would do? 10-20hp?

My last build was similar. Same cam & Comp 1.5 roller rockers on a zero deck .030 - 360 with Edelbrock heads, RPM, 750, 1-3/4 Hooker Super Comps.
 
Real nice comparison, Robb. Thanks. As you say......it wasn't a bad little motor to begin with. Nice improvement though.
 
rumblefish360 said:
That's true! The humidity does creep up north. I myself, living on an island can not escape the steamy water in the late summer. It becomes murderous here late July & August.

Also true.....

Real actual tests with real world builds. No guessing. Bamm! There it is, just the facts.

J.Robb, what do you figure the
RPM intake would do? 10-20hp?

My last build was similar. Same cam & Comp 1.5 roller rockers on a zero deck .030 - 360 with Edelbrock heads, RPM, 750, 1-3/4 Hooker Super Comps.
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Those heads on a true zero deck 360 with a Comp 294S I can't see why it wouldn't be a 430-440 hp piece easy. On this 340 I would expect the RPM to be 5-10 hp better with the same in torque--probably not worth it unless torque below peak came way way up. J.Rob
 
Mopar 576 castings were sold by Mopar performance as a upgraded replacement for the 308 heads. Has the same exhaust port as the magnum heads. No dog leg,a nice smooth radius.
I have the part#574 made off the 576 casting. It was 2.02 valve version and called the 340 replacement.
 
m880 said:
Mopar 576 castings were sold by Mopar performance as a upgraded replacement for the 308 heads. Has the same exhaust port as the magnum heads. No dog leg,a nice smooth radius.
I have the part#574 made off the 576 casting. It was 2.02 valve version and called the 340 replacement.
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Yes the exhaust is very nice on these heads. Intake flowed a dismal 191 cfm which is what the exhaust flowed after reworking--Lol. Nice heads to work with-still a set of lightly worked Mag's would probably wake this example up by 15-20hp yet. J.Rob
 
Refreshing to see HONEST, real world testing. Thank you sir for taking your time to post!
 
I will echo the other responses. Nicely done! This is the kind of info we can all use.
 
toolmanmike said:
I will echo the other responses. Nicely done! This is the kind of info we can all use.
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Head work. I keep my throats small @ 88.5% of valve diameter. J.Rob

IMG_20160830_153323.jpg
 
Awesome build-thanks for sharing the experiments and progress on here. Makes me want to swap the roller in my 5.2 Magnum for a slightly smaller solid cam...just gotta buy the accompanying adjustable parts. At that point, I'd probably just buy new heads and rebuild the bottom end with some decent flat tops.
 
Nice build and reinforces the BS that was in the 340 Dyno Derby article, 340, stock heads, XE268H making 391HP... Yeah sure... :)

Good job on the upgrades.
 
Curious, why the LD4B instead of a bigger Performer Air Gap, LD340,or even a stock cast intake?
 
Louie70Dart said:
Curious, why the LD4B instead of a bigger Performer Air Gap, LD340,or even a stock cast intake?
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The customer wanted to retain everything he could and save $$$. Don't blame him really, you could buy parts and this project could spiral out of control easily. J.Rob
 
RAMM said:
Yes the exhaust is very nice on these heads. Intake flowed a dismal 191 cfm which is what the exhaust flowed after reworking--Lol. Nice heads to work with-still a set of lightly worked Mag's would probably wake this example up by 15-20hp yet. J.Rob
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Yes the intake sucks but was advertised as being a porters head.
First set Mancini sent me had the pushrod holes offset,out of phase on the pushrod drilling fixture? So I called them and no argument,sent Me another set to the garage I worked and picked up the others. Showed a guy I worked with in the Mopar performance catalog the heads like 5 mins.after transfer.damn,damn i noticed at that point they sold a t/a replacement head with offset pushrod holes,damn it.
 
I would have liked to see a backup test with the 750 vacuum secondary on the original motor.
 
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