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Holley Contender Intake 300-36 vs AIR GAP RPM

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Holley Contender Intake 300-36 vs AIR GAP RPM

WScott WScott
New User | Posts: 40 | Joined: 03/12
Posted: 12/10/12
03:38 PM

i have a 406 sb in a 67 chevelle, it has 186 casting, 64cc heads with 2.02 and 1.6
valves. i want to install victor jr. cyl heads with 2.080 and 1.6 valves
my ? is i am running a holley contender  300-36 intake, the specs for the intake
say that it is from off idle to 7200 rpm. since i will never see that kind of rpm i
was wondering if a edelbrock rpm air gap would be a better choice. also why is the
air gap rated at 1500 to 6500 and my contender dual plane is rated so high to 7200
the cam i have is a comp cam cs 280h-10, gross valve lift 486 intake and exhaust
dur. @ .050 is 230 across. the old heads are in need of a complete overhaul so i
decided to splurge and go with newer technology, other than that the car has a
4 speed stick with 3.55 rear gears and has a truck load of torque and is a blast to drive
i enjoy reading the posts everyday and and can honestly say that
i have learned a lot off the experience of you  guys
thats why i am asking  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 12/10/12
10:17 PM

Changing to the Victor Jr. Cylinder Heads. With a 215cc intake port,I would stay with the Holley Contender intake. You don't want to run out of air with the 2.080/1.6 valves. Upstairs in your RPM range. If you think it was a bear with the old 186's. I don't know if you young guys actually power shift any more. If you can hang on to the steering wheel!
  You have enough cam to spin that engine to 6600RPM+. Just set the base timing @12* and 34* all in at 2500RPM if you get good gas. One other thing. Whatever heat range spark plug you are using go a step colder in heat range. In the summer when it gets hot go 2 steps colder.....Any questions ask away.... Cool  Grin


zman123 zman123
Enthusiast | Posts: 531 | Joined: 06/08
Posted: 12/11/12
08:11 AM

What kind of pistons are you using? Flat top? Dished? if dished how many cc is the dish? Deck height?  What compression ratio do you figure you have? the reason I ask is I have a 406 SB and I used 200cc World Sportsman 2 heads on it thinking that at lower engine speeds where it operates most of the time the intake charge velocity would stay a little higher keeping the fuel in suspension better. Anybody else out there have ideas on this subject?  

76Skylark 76Skylark
Guru | Posts: 853 | Joined: 12/11
Posted: 12/11/12
12:50 PM

Oh yea we got Opinions, look at the 327 engine in engines heading.  

WScott WScott
New User | Posts: 40 | Joined: 03/12
Posted: 12/11/12
02:19 PM

i have flat tops, the comp ratio is 10-1 , i also am running a holley 750 vac sec carb  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 12/11/12
04:37 PM

  Like I said if that ran good with the 186's just hold on with the newer heads. You will be surprised at the difference. If it doesn't bogg with the 750 on it leave it alone. Of course tune it to the new heads.
  Just some FYI Don't toss the 186's. Those are becoming scarce, the purist's will be looking for them. I sold a set of Bare 461X castings for $450.00. They needed a complete rebuilding


skyeking skyeking
Addict | Posts: 2738 | Joined: 08/09
Posted: 12/13/12
04:53 PM

Hi Bob,
 Those 461's could be reasoned for power.
 I'm certain that Poncho man can give all
 the details to the affirmative. Good luck People...