Do I need a bigger cam?

S

stevensmach

New Member

Jan 2, 2003

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ga

Sep 26, 2004

#1

• Sep 26, 2004

• #1

Ok, this is what I have. 351w, ported twisted wedge heads, weiand stealth intake, street avenger 670, 1.6 roller rockers, msd ignition, and currently a comp cam with .224/.500 on intake and exhaust, 389 gears, headers and borla exhaust. Up until a month ago I had a edlebrock performer 351 intake and changed it out for the stealth and didn't notice a difference at all. With what I have, should I go with a bigger cam?

 

ratio411

Founding Member

Apr 21, 2002

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Pensacola FL

Sep 26, 2004

#2

• Sep 26, 2004

• #2

IMO you need a single plane intake.
Either that or you could try a larger carb.
Dual plane intakes tame carb size, so they can better utilize a large carb.
If you try a single plane intake, start off with the same carb you have.
There was surely a difference in the intake swap, but not like you would see with a Torker or Victor.
Personally, I would use a Torker with that combo.
My .02
Dave

 

thehueypilot

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Feb 25, 2004

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Sep 26, 2004

#3

• Sep 26, 2004

• #3

You need a bigger carb....try a 750 cfm. You could try a 1.7 ratio rocker arms to increase your lift to take advantage of your deep breathing heads. If you drive this car on the street I would shy away from a single plane...... unless you race it full time. Add another .02

 

ratio411

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Apr 21, 2002

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Sep 27, 2004

#4

• Sep 27, 2004

• #4

I like the idea of 1.7 rockers.
Good call.
Just make sure your springs can take it. If you got new springs matched to the cam, chances are you have plenty of room for the mod.
I still stand by the single plane mod though. If you changed to a dual plane and didn't get the power you wanted, it sounds like you would be pleased with a mild single plane.
I know from experience that switching from single to dual plane made me very unhappy with the losses. I went back to single plane quickly. I only swapped it off because all my friends bought into the dual plane myth and talked me into swapping. They said I would gain mucho low end without top end losses. It ended up the gains were unoticable on bottom and the mid/top losses were profound.
You can put a larger carb on the dual plane, I think it needs it, but you won't see the gains you would get from the 1.7s or SP intake.
Dave

 

washMO66

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Oct 30, 2001

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Washington, MO

Sep 27, 2004

#5

• Sep 27, 2004

• #5

Single plane intakes are streetable!!!!!!!!!!!

Don't be taken in by the "only use a single plane if you race myth"

Single planes "can" work much better in many applications as in some cases a dual plane may be the right choice. In my opinion I think you would be in tall cotten if you went to a single plane and ditch that street avenger for a mechanical secondary carb.

Although my application is slightly different I will tell you that I went from a performer RPM dual plane and a 670 street avenger to a Victor JR and a mighty Demon 650 and IT IS LIKE NIGHT AND DAY. I do race but I also drive it on the street and the street manners did not suffer one bit.

PS - At the track the car went from running 11.86's to 11.40's. That alone should indicate the power you may not be taking advantage of.

.02 + .02 + two bits...........

 

S

stevensmach

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Jan 2, 2003

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Sep 27, 2004

#6

• Sep 27, 2004

• #6

Thanks guys, btw this is mainly a street car. on dr's I run 8.30-8.4 but it just doesn't seem to pull like it should, could that be because of the intake? What do you think the best intake/carb combo should be? oh yeah,Italso has a mildly built AOD. Thanks

 

brianj5600

Active Member

Sep 19, 2003

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Middle TN

Sep 27, 2004

#7

• Sep 27, 2004

• #7

I say it is the cam. That cam was in comps catalog in the mid 80s. They have learned so much since then it is not funny. I have also heard that tftw heads stock need a little help on the exhaust, yours are ported so it might not need it, but I bet they are still a little soft on the exhaust side. I also beleive that a 347 will love a vic jr designed for a 302, his combo is the ci that the intake is designed for. I also don't see too many other choices for a 351. Keep the carb and intake, but upgrade the cam.

 

ratio411

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Apr 21, 2002

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Pensacola FL

Sep 27, 2004

#8

• Sep 27, 2004

• #8

With those heads, that cam is running plenty good for the street IMO.
Most of the newer stuff is dual pattern cams, IMO that would hurt your exhaust port velocity on a set of good flowing heads.
Pick up a used Torker 2 for 50-100 bux and slap it on there. If you don't like it, nothing really lost but a few hours and intake gaskets.
I am in the market for that intake, so I would buy it off ya.
One thing I noticed about going from a Torker to an RPM on my 302 was that the engine was 'lazy' with the dual plane.
With the mild single plane, the engine revved much quicker and responded better. Of course I was running 4.11 gears, but with anything over 3.50 there should be plenty of noticable revs on acceleration.
I know I keep butting in here, but I am conviced that changing your intake before jumping into the cam or even forking out dough for an expensive carb, is the way to go.

 

12sec67

Active Member

Oct 6, 2003

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San Diego, Ca

Sep 27, 2004

#9

• Sep 27, 2004

• #9

i like the bigger carb idea along with the 1.7 rockers - leave the gear alone.