cam question
Senior User
Joined: Sep 2000
Posts: 161
Likes: 0
cam question
guys-
would it be worth it to put a nice street (NOT race) dual-pattern cam in a 390, if the 390 only had a 2-barrel manifold and carb?
or would you need the 4-barrel intake and carb to make the cam worthwhile?
the reason i ask is, i have taken a few days off next week, and all i have scheduled is boneyard-crawling. i have a line on a parts truck with power brakes and a 390. but i can't remember if the 390 was 2 or 4 barrel. (the motor in the parts truck isn't original.)
thanks,
sam
would it be worth it to put a nice street (NOT race) dual-pattern cam in a 390, if the 390 only had a 2-barrel manifold and carb?
or would you need the 4-barrel intake and carb to make the cam worthwhile?
the reason i ask is, i have taken a few days off next week, and all i have scheduled is boneyard-crawling. i have a line on a parts truck with power brakes and a 390. but i can't remember if the 390 was 2 or 4 barrel. (the motor in the parts truck isn't original.)
thanks,
sam
Senior User
Joined: Mar 2001
Posts: 136
Likes: 1
From: Highlands USA
cam question
Sam, you want to match the cam to your intended usage i.e. low end torque, rpm range, etc. I've seen some two barrel equiped vehicles turn in some extremely low ET's on the strip, and some racing classes are limited to two barrels. Keep in mind that if you compare a 500cfm 2bl to say a 600cfm 4bl, the 4bl will give better economy, performance, and throttle response than the 2bl! It is all related to vacumn and air flow/ velocity through the carb venturis. Hope this helps you. trey gorbett/ 78 F250-Bronco Hybrid "SuperBronco" 460,NP435,NP205,Dana60 front,Sterling 10.25 rear,4.10's, 17/40x16.5 GroundHawgs http://communities.msn.com/treys4x4
Senior User
Joined: Sep 2000
Posts: 161
Likes: 0
cam question
the truck is just a driver- nothing special. some occasional light hauling, (small boat, etc.) mostly just tooling around. i don't keep my foot in the floorboards.
had always heard that the dual-pattern cam helped it to breathe better, but didn't know if the 4-barrel setup was also required.
thanks,
sam
had always heard that the dual-pattern cam helped it to breathe better, but didn't know if the 4-barrel setup was also required.
thanks,
sam
Cargo Master
Joined: Aug 2000
Posts: 2,931
Likes: 12
From: SW Michigan
cam question
rustySam, no the four barrel is not a requirement to use a bigger cam. Keep in mind that most of the factory cams are very small. The manufacturers have to allow for folks like Aunt Matilda who idles four hours at a time and never drives over 35 mph. You could go bigger and keep the stock setup on the intake. Anything you do to help breathing is going to help power. If you are running a 390, the exhuast is in need of an upgrade to duals at least, adding headers will help even more, the factory exhaust is rather restrictive. Do you need a few suggestions on cams ? DF
Cargo Master
Joined: Apr 2001
Posts: 2,697
Likes: 46
From: Vancouver
cam question
I used Comp Cams 33-206-3 with excellent results. Specs are 255/265 at .006 and .460/.495. I have a 390 2V, 9:1, cast ex manifolds and 2.5 dual ex. Rear is 3.73. The cam gives great low and mid power, smooth idle, and a little more noise.
Eric
Eric
