Choosing a new carb and intake

[79scottsdale400]

So I'm swapping the double pumper that came with the truck for a demon. Which model would be best street demon or road demon and I'm thinking of a 750cfm. I do plan on camming the 400 with a 268 voodoo cam. I don't know of any good intake manifolds. Anybody have any ideas?

 

[79scottsdale400]

Anybody??

 

[bigcountryguy19]

I like edelbrock intakes myself, what rpm range is the 268 voodoo cam? You should always match your cam rpm to your intake rpm. Same with the carb, read what they are best intended for. I only build high torque low rpm engines, cause that's what I like in my 4x4's. I like edelbrocks performance packages, I have had very good luck with them.


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[79scottsdale400]

Hydraulic. The most awesome 268 cam ever produced! Out-powers all others! This High Performance street cam likes 2400 RPM stall, 700 cfm carb, dual plane intake and headers. Makes un-equaled power to 6200 RPM with proper valve springs. If you're looking for a Very Strong cam with great street manners then this cam is it.
Advertised Duration (Int/Exh): 268/276
Duration @ .050 (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .489/.504
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1800-6200
Includes: Cam & Lifters (#71817PR-16)


There's the specs from their site. I want low end and mid. Since it's 4x4 4 inch lift and 35s. 400sb under the hood

 

[bigcountryguy19]

That tells u all you need to know, use that info when buying an intake and carb. Don't forget valve springs.


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[79scottsdale400]

It says it likes a 2400 stall. Excuse my newness to this but what's that. All I know is something with a tq convertor

 

[79scottsdale400]

Also do I need any info on gear ratio when doing this?

 

[SlickGTP]

For the low end torque you're going to want a dual plane intake of some sort. The single planes are better for high RPM applications.

When choosing a cam, you have to take everything into consideration. RPM range, Gear Ratios, Tires, etc... I say this as I'm still learning about what one needs to consider after already installing a cam that is just a tad too much for what I need.

Figure out what RPM range you're typically going to be running in and base your decision on that. To do that you'll need to know the tire size, rear end ratio, transmission ratios, etc. Are you going to be running the trails mostly, city driving, highway? All considerations.

All that said... In my 454 I'm running the Lunati Voodoo 276/284 Hyd Flat Tappet and love it. Now, I'm trying to figure out how to set the rest of the truck up to work best with the cam. lol... It works alright for now, but it could be better. Looking back I also wish I had gone with a hydraulic roller. Would've cost more up front but would have been worth it in the long run I think.

 

[hirschdalechevy]

Thats quite a bit of cam for a stock low compression 400 , you may loose some bottom end with your selection. 35's , stock gear's , automatic trans , (if that what's you have) will problably be soft on the bottom end but may run out well. Just my 2 cent's

 

[79scottsdale400]

I don't know if the gears are stock or not. When I changed gear oil the rear looked brand spanking new. I want a cam that's gonna give some oomph when I'm trail riding and splashing around in some mud puddles. And no I'm not gonna hit big mud holes or anything
If you got a better cam idea go ahead tell me. I'm not as experienced with these motors. Especially ones this old.

 

[bigcountryguy19]

I built a 355 with flat tops, 76cc heads and the edelbrock performer package. (Cam, lifters, valve springs, timing set, and intake with a 600 cfm Holley carb. I had 3:55 gears and 33 inch tires. It had impressive power. I ran stock exhaust manifolds too. I hate headers.


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[79scottsdale400]

Lunati's Voodoo series of Hydraulic camshafts deliver more area under the curve than any other series of Hydraulic camshafts. This means more throttle response, quicker acceleration, more vacuum, better efficiency, combined with maximum horsepower and torque!
Hydraulic. Mid-level performance street cam with excellent drivability. Exceptional replacement for muscle car type cams with automatic transmissions. Works well with stock type exhaust manifolds and dual plane intake with mild 4 bbl carb. This is an Awesome 4X4 and performance marine cam.
Advertised Duration (Int/Exh): 262/268
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .468/.489
LSA/ICL: 112/108
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1400-5800
Includes: Cam & Lifters (#71817PR-16)


This seems to be a bit better. A good mild cam.

 

[Thunder]

I know I'm probably a little late with this but I've been out of town for a while. your second choice would of cam, the 262, would be a better choice for your motor. It sounds like you are dealing with a stock engine. Stay with a dual plane manifold. 650 cfm would work better for you. I you do a lot of off roading check into Predator carbs. Great off road, good on the highway.