New intake manifold worth it?

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DartVadar

DartVadar

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Ive had my 360 together in my dart swinger for a while now and been driving it around all summer without a hiccup in the engine. It makes really good power and is nice and healthy so I have no problem. But ive been thinking that my intake manifold may not be completely correct for my engine combo. The intake is a weiand dual action plus dual plane.

Engine specs:
360
Holley 650 sitting on top
KB 107 pistons at zero deck
Stock crank and rods
edelbrock heads with matching springs for camshaft
lunati solid roller 237/243 @50 and .566/.578 lift which is good from 2500-6600 RPM
Roller rocker arms
Dougs headers out to 2.5 inch exhaust at the rear bumper

The car has a 999 transmission with a soon to be installed 3000 torque converter and 4.10 rear gears.

Would it be beneficial to change out the intake manifold for one that is more for higher rpm? or would It not be worth it to change it. Has no issue lighting up the 255 rear tires so there is plenty of power as it sits now, just wondering if Im leaving anything on the table.
 
That's a pretty good intake, especially for a street car.

650 carb could be leaving a little on the table though.
 
Do you spend much time in the 5,000 to 6500 pm range ? If not don't see much of a benefit , besides you'll probably gain a few 10th's of a second in the 1/4 mile , is it really worth it ? You won't see a big difference on the street
 
Put a Holley 750 on it,, that'll put the grin back on your face,, and cheaper than a manifold.. lol ..

Pick one up at the next swap meet,, should get it for less than $100,, kit it,, and luv it,, use the short yellow spring in the vac secondary.. You'll definately feel a difference..

cheers
 
I do drive it hard when I do, and it loves to rev so I dont mind bringing the RPMs up, but yes its not all the time so maybe ill leave the manifold where it is.

I have been wondering about the carb as well, so a 750 would be a better option? Oddly enough I tested it with an 850 carb and the throttle response was night and day, didnt get much of a driving test because it was way too lean for some reason.
 
650 runs out of breath at the top end on my car as well , 750 would be better on the top end , but I'll live with the 650 , only at the track 7 -9 times a year . Plenty good for the street , 750 might hurt mpg , going from AVS to Holley street avenger hurt mpg so no more hurting mpg for me
 
jerry6 said:
650 runs out of breath at the top end on my car as well , 750 would be better on the top end , but I'll live with the 650 , only at the track 7 -9 times a year . Plenty good for the street , 750 might hurt mpg , going from AVS to Holley street avenger hurt mpg so no more hurting mpg for me
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I feel for you man,.. You only get to put a smile on your face 7 - 9 times a year,, why, cuz that's the only time you put it to the floor... You built a storming motor, prob head work,, headers,, cam,, and put a 650 on cuz you wanna smile 7 - 9 times a year..

Do you believe a 360 engine running at,, say 2500 rpm would use less fuel with a 650 cfm,, as opposed to a 750 cfm..?? ( equal A/F ratios )

I drive, and get paid to build, cars that put a **** faced grin on your face every time you punch it,, on or off the track,, why limit you fun by running a puny carb, and kid yourself that you only wanna get ON it at the track..,. LET your right foot worry about gas mileage..

I like driving around with the ability for perma-grin at any given moment,, and I grin a LOT.... lol .. jmo

cheers
 
What kind of Holley 650? 4777 Double pumper? If so, a new Holley or Proform main body will turn it into a 750.
 
You're leaving a good amount of ppower on the table with that intake and carb. I'd replace it with the Air Gap or an M1 (gasket match either one) and add a carb of at least 750cfm. If the goal is more racing and the 4.10s going in I'd go with the M1 single plane
 
I'd spend some money on fitting some bigger tires on that hummer first.Until you get traction, you're kinda defeating the purpose of that big cam anyway. Or did you just put it in there for the awesome sounding idle.
My engine combo is much like yours. I have a 68 FormulaS clone, stick car.My car was "dangerous",until I put 295s on her. Then it was too quick(IMO) for street. I swapped out the 292/509, for a 223*fast-rate. That was a sweet cam, but when it dropped 2 lobes, I replaced it with a 232* fast-rate. Now it's just right,for me. And it doesn't send me into 360s at every chance it gets anymore.
BTW, I got a kick out of the comment regarding fuel mileage.
 
moper said:
you're leaving a good amount of ppower on the table with that intake and carb. I'd replace it with the air gap or an m1 (gasket match either one) and add a carb of at least 750cfm. If the goal is more racing and the 4.10s going in i'd go with the m1 single plane
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x 2.
 
I'd put an air gap on it if you do swap out manifolds.

Not enough converter to cover the big hole in mid range an M1 single plane leaves with that converter.
 
Cam, Gears, Converter, Ede heads, Headers. Sounds like its time for an Air-Gap and a 750 carb.
 
crackedback said:
I'd put an air gap on it if you do swap out manifolds.

Not enough converter to cover the big hole in mid range an M1 single plane leaves with that converter.
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I agree with this. I don't believe the single plane M1 will catch up to the air gap until about 5000 rpm. The small gains of the M1 above that point won't be enough to offset the losses below. JMO, of course.
 
How about the holley strip dominator? I used it on a 360 x-heads and a 280/474 cam mopar. I replaced the LD4B intake because of heat crossover issues (gets mighty toasty here in the south). It gained power everywhere! Believe it or not even down low @ least the seat of pants feel I got. Oh I also run a thermoquad 850 & 3.55 gears.
 
I don't think the M1 will leave any hole given the cam and rest of the package. Not saying the RPM might not be close, but I think the M1 is a better match. IMO anyway.
 
moper said:
I don't think the M1 will leave any hole given the cam and rest of the package. Not saying the RPM might not be close, but I think the M1 is a better match. IMO anyway.
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He may find that hole when he changes to a higher rear gear,, if the 4:11's don't work out, for the street,, (as many discover). jmo..

cheers..
 
From what I am taking either an m1 or an air gap with a 750 on top would be a better combo. The old carb is just a vacuum secondary 650 so I dont believe I can change the main body out to make a 750?

The converter is going in during the winter, and I am yet to actually order it (getting a custom one built for the combo) but the 4.10s are actually already in the car and I love them! Traction is an issue though but Im not too concerned with that.

My entire package is more of a high rpm one, I really notice that with this cam it makes zero power up until about 2500rpm, but I dont mind that at all. I didnt choose it for the sound either, it was recommended for me and I think it was a great choice. The biggest problem with the combo now is the converter, its a new stock unit I believe, and it takes a bit longer to get into the power band so with that changed out itll be a new car.
 
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