Intake bottleneck thoughts

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TrailBeast

TrailBeast

AKA Mopars4us on Youtube
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I rarely tell people what I am doing with my car, and mostly because I don't need extra opinions but this subject is something others may like to know so here we are.:D

When I built my drivetrain I had a limited amount of money to work with so I bought a totally stock Magnum with approx. 96k on it.
I knew I was replacing the heads and cam right away, and used the Engine quest CH318B (LA intake drilled) heads with 1.92 intake valves, good positive sealing stem seals and the Hughes 1110 spring kit with the extra clearance retainers.
I wasn't going for all out horse power, but a nice reliable daily driver.
The cam is 214/224@.050 .512 lift on a 110

I used the Edelbrock 600 cfm carb and 2176 318/360 Performer intake I had on my 318.
Now awhile later I am going back over a few things I knew were not quite optimal even just for a daily driver.
Even though the motor runs really nice and has been super reliable, I have to somewhat laugh about the intake to heads ports situation.
The EQ heads intake ports are around 1/4 inch larger all the way around than the 2176 ports are, and though I know it would be way worse if it were the other way around it seems I can't stop thinking about doing something about it, as I can't help thinking the intake charge is probably slowing down right where it probably shouldn't for the mid RPM torque the cam is ground for.

Any thoughts on if a different intake would be better for ft lbs but still keep everything under thee hood and keep the dual plane street manners?
It sure wouldn't hurt anything to have more power available, but would a different intake make that much difference for daily driving.

I can use the excuse that the 2176 would better suit the Wifes stock 318 with a 1968 340 grind cam.:D
 
Beats the **** outta me.

(Rodney King's quote when asked his opinion of the LA Police Department.)
 
The intake should be the same size as the port, and get slightly bigger towards the plenum.

Never make the intake smaller than the head. Power killer every time. I'd rather have the intake bigger than the head than the other way around.

Takes about 20 minutes to figure it out on a flow bench.
 
yellow rose said:
The intake should be the same size as the port, and get slightly bigger towards the plenum.

Never make the intake smaller than the head. Power killer every time. I'd rather have the intake bigger than the head than the other way around.

Takes about 20 minutes to figure it out on a flow bench.
Click to expand...

That right there was what I wanted to know, as I was thinking port velocity might be more important for torque vs size.
Apparently not in this case.:D
I also saw that same Engine masters episode recently that you did, and that was interesting. (mid range cam/heads) and still good power compared to larger.



ScampMike said:
Edelbrock Performer RPM AirGap - read this: Make Big Power With Your Magnum 5.9L Mopar With These Heads! - Hot Rod Network
Click to expand...

I have read so many things on these engines and heads it could almost fill a book.
Still, there were little bits and pieces in that article I hadn't seen yet.
Mostly some of the background.
Thanks.

Both of you confirmed it.
The Wifes stocker 318 is going to get the Performer.
 
I'd port match it . Perforer may not make as much power as an RPM but for a driver I wouldn't lose sleep over it.
 
skrews said:
I'd port match it . Perforer may not make as much power as an RPM but for a driver I wouldn't lose sleep over it.
Click to expand...

I was kind of wondering about that also.
(matched vs different intake) but if I do that the Performer won't be any good for much else, like the Wife's 318 with the small ports.
Probably change out mine just because of that.

Thanks.
 
Go larger and don't worry about it. It won't hurt your low end as the cam is not very large anyway. I ran a 1st gen Torker single plane on my 351C, along with 1-7/8" headers, and it did not EVER lack for low end torque or almost stock-like driving manners. The cam selection took care of that.
 
Or just the regular Performer RPM- That's what I have on my mild 360 works fantastic Trail.
 
You got it right the first time - stick the performer on the 318 and get a manifold for a 340/360 for your motor. Performer RPM Air Gap, or in my opinion a vintage Edelbrock LD340 and then gasket match the ports
 
RustyRatRod said:
Beats the **** outta me.
^^^^^^^^^^^^^^^
(Rodney King's quote when asked his opinion of the LA Police Department.)
Click to expand...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LOL !!
THE SMALLER INTAKE MANIFOLD PORTS WOULD SURE STOP ANY REVERSION ! Unless u make the whole runner the same size, port matching it probably won`t help. Can u get a perf. rpm to work?
Bet that would help !
 
famous bob said:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LOL !!
THE SMALLER INTAKE MANIFOLD PORTS WOULD SURE STOP ANY REVERSION ! Unless u make the whole runner the same size, port matching it probably won`t help. Can u get a perf. rpm to work?
Bet that would help !
Click to expand...

I'll be watching for one.
 
famous bob said:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LOL !!
THE SMALLER INTAKE MANIFOLD PORTS WOULD SURE STOP ANY REVERSION ! Unless u make the whole runner the same size, port matching it probably won`t help. Can u get a perf. rpm to work?
Bet that would help !
Click to expand...


This just isn't true. Trying to use the manifold to control reversion is a power loser every single time.
 
The cfm drops some, but more so "speeds up"...not "slows down" probably helps throttle response till about 2800 ish and then negatively effects power after 4500+
The gain in between those rpms is probably 8-14 with a port match.
It's up to you, it isn't much work to correct it.
 
My understanding is the 2176 manifold is tapered to suit 318 size heads but can easily be ported out to 360 port size?! I have one here I can feel the taper. For a car that's not a race car I'd just port match the 2176.
 
70coupe said:
My understanding is the 2176 manifold is tapered to suit 318 size heads but can easily be ported out to 360 port size?! I have one here I can feel the taper. For a car that's not a race car I'd just port match the 2176.
Click to expand...

HEY!, watch it now.
What am I going to do for an excuse to get a new intake if I do that? :D

That was what I was thinking though, since it runs just fine for everything I do with it.
It's a daily driver that takes long road trips on occasion.
Thanks.
 
TrailBeast said:
HEY!, watch it now.
What am I going to do for an excuse to get a new intake if I do that? :D

That was what I was thinking though, since it runs just fine for everything I do with it.
It's a daily driver that takes long road trips on occasion.
Thanks.
Click to expand...
Follow the plan, be miles ahead of the game.:thumbsup:
 
My LA360 plow truck runs great with the 318 Performer on it. It's more about where you want the power. I don't ever go over 4200, and most stuff is 3500 or so max, with cruise at 2K-2400. It's been on there 10 years of more now. I'd say if you're not normally running full throttle over 4k, it's fine and it's all in your head. Up to you. SOme people get bugged by stiff like that.
 
I keep coming back to a couple questions. If this was my boggle, would I be satisfied with the 2176 reworked, even if I thought I could feel the improvement on the street, or at the strip for that matter? Would I constantly wonder if the bigger volume of the air gap would be even a little better? What if I cleaned up the air gap before I put it on; how much more would I get? Screw that! I'll get the air gap so these questions don't keep me up at night.
 
get the air gap.it was a large improvement over my ld340, contrary to popular opinion!now to try strip dominator with tq superquad
 
I’d like to see that myself.
If it were possible to keep the “actual” cfm the same. That would be very cool.
 
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