Camshaft Recommendations?

[Niedhogg]

I'm trying to get a little more power out of my 304, and could use some suggestions..

I have a '79 304 that was a totally stock smog engine when I started. I have removed all the emissions, and have added headers, an Edelbrock Performer intake, and a 470cfm Holley truck avenger, and converted the ignition to HEI... It just seems like it should have better accelaration, it's really sluggish, and it is using copius amounts of gasoline. I know there are other factors, I am unsure of the gearing and I have 35" tires. I am planning to check the float levels on the carb today as I think the rear bowl may be running over, because the last time I had the carb off the back two barrels were really wet at the base gasket. The carb is new from Holley and has the factory settings. Could that be causing my sluggishness?

I was also going to upgrade the cam during the build, but I had a time restriction that I just didn't feel like I could finish the project if I'd tackeled that too, so, what would you guys suggest for a cam size for my motor, I'm not really worried about the gas cosumption, but for all the gas it's using I'd like to at least have the power to show for it..

[Manhattan]

How do you use the Jeep? If it's all street, then a cam might be the way to go. But - and it's a big but - if you drive the Jeep off road much (ever) I'd stick with a stock or very mild cam. As you know, on the trail, you spend 90% of your time under 1,200 rpm - and a lot of it under 900 rpm. A "big" cam, while fun on the street, will really suck on the trail. Crawling with a lopey motor is a bitch.

It sounds like the top side of the motor is dead on - right size carb', the ignition, etc. Those carb's are usually set pretty much perfectly out of the box too.

You've got headers... what's the rest of the exhaust system - duals? 2.5"? 1 or 2 mufflers? Cats? Wondering if you've lost too much back pressure?

Do the math on the axle and report back - if you've got 3.31 gears and 35s... your answer might be right there.

[Niedhogg]

Originally Posted by Manhattan How do you use the Jeep? If it's all street, then a cam might be the way to go. But - and it's a big but - if you drive the Jeep off road much (ever) I'd stick with a stock or very mild cam. As you know, on the trail, you spend 90% of your time under 1,200 rpm - and a lot of it under 900 rpm. A "big" cam, while fun on the street, will really suck on the trail. Crawling with a lopey motor is a bitch. It sounds like the top side of the motor is dead on - right size carb', the ignition, etc. Those carb's are usually set pretty much perfectly out of the box too. You've got headers... what's the rest of the exhaust system - duals? 2.5"? 1 or 2 mufflers? Cats? Wondering if you've lost too much back pressure? Do the math on the axle and report back - if you've got 3.31 gears and 35s... your answer might be right there.

Ok, so I have dual 2-1/2" through mufflers all the way out the back, and right now, I'm just driving it. But, I AM going to wheel it, AND I'm planning on towing a small trailer with camping gear, or my Harley, depending on the weekend. And all I'm thinking about, cam wise, is just like the first notch, rv type cam. I'll try to check the gearing this weekend, but like I said, it barely gets out of it's own way now which I figure is because of the gearing, so I can't imagine trying to tow a trailer, or even trying to get through some deep mud. The cams I've been looking at are just basic, off-idle type torque cams. Plus, right now I'm running an automatic.

[Old Dog]

I have a comp cams 4x4 cam in mine (1000-5200 rpm) and like it.
I have a 350 chevy with an auto.

I'm betting you need a gear change.

[Niedhogg]

Originally Posted by Old Dog I have a comp cams 4x4 cam in mine (1000-5200 rpm) and like it. I have a 350 chevy with an auto. I'm betting you need a gear change.

I'll be working on the gear change later this summer with any luck, along with axle upgrades. I figured the cam change would be a much cheaper route to some more power right now, and then the gear change would just accentuate the power gain, right?? I might have enough to work over the heads a bit, would that be worth my time and money? What can be done with the factory heads? I can't imagine it would hurt anything..

[jeepboy45]

I'd go with a cam with a bit longer than normal duration. The main problem with a 304 is the heads.... the valves are SMALL....

As was mentioned, you dont want a ton of cam lope, but you need to get it to breathe

.

[Niedhogg]

Originally Posted by jeepboy45 I'd go with a cam with a bit longer than normal duration. The main problem with a 304 is the heads.... the valves are SMALL.... As was mentioned, you dont want a ton of cam lope, but you need to get it to breathe .

Kind of what I thought, I'm sure someone makes bigger valves for them. I used to have a '74 AMX in high school, pretty sure there was some hp stuff available then...

[CJ]

Originally Posted by Niedhogg Kind of what I thought, I'm sure someone makes bigger valves for them. I used to have a '74 AMX in high school, pretty sure there was some hp stuff available then...

You cannot put larger valves in a 304 head without notching the cylinder walls or the valves will hit. Also, since the valves are shrouded, negligible HP gains are realized.

[jeepboy45]

Originally Posted by CJ You cannot put larger valves in a 304 head without notching the cylinder walls or the valves will hit. Also, since the valves are shrouded, negligible HP gains are realized.

x2 .. thats what I was gonna say.. but CJ is quicker (AND he has the advantage of owning the site and probably SLOWED down my post so he'd seem smarter!!!) LOL .............Just kidding CJ.... (great, I'm gonna get reprimanded for this....haha)

[CJim7]

Yeah...there's a lot involved in going with larger valves...the headwork alone is worth the price of a couple new engines.
And for that, you could pick up some AMC aluminum performance heads.

Have you tried playing around with your timing?