Cam help please
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Cam help please
I'm planning on running the Offenhauser intake with the Holley truck Avenger 670 cfm and a heddman header duel 2 1/2" outlet, and plan on running 2 1/2" exhaust with minor head work. Which cam do you guys recomend? I have a couple ideas I need the best for my buck.
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From: Iowa
What rpm range are you running? Are you modifying the engine internally? Different compression? Do you want low rpm torque, or a racing engine.
If you're just looking for a gutsy truck engine, which I suspect, something with between 205 and 215 degrees of duration on the intake at .050" would be about ideal. I like comp cams, and they have one advertised as a "260" that would be about perfect.
I'm with stractor - you really don't need any carb bigger than 500 cfm... I run a 525 Road Demon on mine, and it's a big plenty. 600's can work, but you'd have better driveability staying smaller. 670 is a monster of a carb, suitable for a healthy small block v8 or a stock or smaller big block...
If you're just looking for a gutsy truck engine, which I suspect, something with between 205 and 215 degrees of duration on the intake at .050" would be about ideal. I like comp cams, and they have one advertised as a "260" that would be about perfect.
I'm with stractor - you really don't need any carb bigger than 500 cfm... I run a 525 Road Demon on mine, and it's a big plenty. 600's can work, but you'd have better driveability staying smaller. 670 is a monster of a carb, suitable for a healthy small block v8 or a stock or smaller big block...
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From: Kalispell, MT
Originally Posted by benwantland
If you're just looking for a gutsy truck engine, which I suspect, something with between 205 and 215 degrees of duration on the intake at .050" would be about ideal. I like comp cams, and they have one advertised as a "260" that would be about perfect...
MontanaFord
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I plan on running between 1000- 5000 rpm. Combustion will be around 9.5-10.5:1. I like the low end torque but need more horsepower at higher rpm. I want the holley truck avenger because of its off-road design. The only size it comes in is 650 and 750 cfm. Teh intake and the header rpm range is listed between 1500-4500 rpm
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Originally Posted by stractor
Hi, are you the owner of a gas pump, because with the 650 Holly you are going to drown the poor engine.
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From: St. Louis, MO USA
Originally Posted by FordGirl_22
How do you figure I will drown the engine when you can run a 302 Ford with even a 750 Holley which is only 2ci bigger than the 300 and I plan on boaring it so it will be bigger than a 302?
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The reason for being able to run the 750 on the 302 is because of the design of the engine. a V8 will spin higher than a 300 any day because of the restrictive design of the 300's head, and thus the 750 won't drown the motor as bad. It will cause it to run pig rich if not tuned properly, but it'll work.
Where the 300 will shine is where you cam it to run...a cam with a power range from 1000-4500 would easily take care of just about anything meet on the street.
Do remember though you are going to have to jet that carb of yours down to make it run properly on the 300. You will indeed have a motor running pig rich with that much carb on it.
Only bore your engine if its nessisary. Everybody knows a 300 is cooler than a 302 any day. No since in getting caught up in a cubic inches war.
It is your motor though, so build it as you wish. Good Luck!
Where the 300 will shine is where you cam it to run...a cam with a power range from 1000-4500 would easily take care of just about anything meet on the street.
Do remember though you are going to have to jet that carb of yours down to make it run properly on the 300. You will indeed have a motor running pig rich with that much carb on it.
Only bore your engine if its nessisary. Everybody knows a 300 is cooler than a 302 any day. No since in getting caught up in a cubic inches war.
It is your motor though, so build it as you wish. Good Luck!
Last edited by desperado_18_2000; Aug 1, 2004 at 04:52 PM.
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my 300 with the holley 390 and the offey intake runs poorly in second gear. It has a hell of a buck at partial throttle if you don't feather it just right. I was expecting to be able to smoke the tires in second with my new power package
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He he, this is a good thread! First, fordgirl, the 390 can be setup to run about as bad offroad as you will likely ever go. Not to brag, because I wouldn't do it, but my buddies did and here is a pic to show what an untuned 390 can handle.
https://www.ford-trucks.com/user_gal...=49429&width=2
That is pretty steep, and it doesn't have the crossover tube or any of that other stuff holley brags about the truck avenger. The floats are side hung, so they don't feel inclines as much. It is a good carb, but it is your truck. You have a good plan of attack. Mine is set up almost identical to what you want to do, and it goes fine. You should have no problem tearing it up
Watch4, it sounds like your timing is a little off. Is the advance receiving good vacuum? I had a broken advance before, and it would do that. Anyway, I would check that, and maybe your accelerator pump? This is where experts need to help you. I am just a guy who tinkers (a lot) Ted
https://www.ford-trucks.com/user_gal...=49429&width=2
That is pretty steep, and it doesn't have the crossover tube or any of that other stuff holley brags about the truck avenger. The floats are side hung, so they don't feel inclines as much. It is a good carb, but it is your truck. You have a good plan of attack. Mine is set up almost identical to what you want to do, and it goes fine. You should have no problem tearing it up
Watch4, it sounds like your timing is a little off. Is the advance receiving good vacuum? I had a broken advance before, and it would do that. Anyway, I would check that, and maybe your accelerator pump? This is where experts need to help you. I am just a guy who tinkers (a lot) Ted
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750 cfm on a 302? Yea, that will work, starting at about 4000 rpm.
I had a 390 cfm on a 289. It would run up to 6000 just fine. Not as fast as 600 would have, but it ran nice and clean and smooth down to 1500 in 4th with 3.0 gears.
The smaller carb is the way to go. You will save your low end and still flow enough to handle it up to 5000. This thing isn't going to "zing" in the rev dept anyway, unless you swiss cheese the crank and flywheel, and get some aluminum rods etc etc.
I had a 390 cfm on a 289. It would run up to 6000 just fine. Not as fast as 600 would have, but it ran nice and clean and smooth down to 1500 in 4th with 3.0 gears.
The smaller carb is the way to go. You will save your low end and still flow enough to handle it up to 5000. This thing isn't going to "zing" in the rev dept anyway, unless you swiss cheese the crank and flywheel, and get some aluminum rods etc etc.
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At 5000 RPM and 100% volumetric efficiency the airflow requirements are 434 cfm.
Here's a link to the airflow calculator page I use - http://www.racewindsor.com/performan...carb_size.html
Brad
Here's a link to the airflow calculator page I use - http://www.racewindsor.com/performan...carb_size.html
Brad
