Cam

[Brandon777]

What is the best cam for a 350, I'm trying to get a slightly rough idle and I want to keep the whole project below $350, and I would like some towing power if I could get it, but not loose any speed. Any suggestions?

 

[MikeB]

A few things we need to know:

engine compression ratio
intake and exhaust specifics
transmission type
torque converter stall speed
rear axle ratio
tire height

In general, it's hard to find a cam with a rough idle that also works for towing, where you typically want to make lots of torque at 1500-3000 RPM. A rough idle is caused by misfires due to lots of valve overlap, which totally kills torque at lower RPMs. And a big cam with too little engine compression further kills torque.

 

[Brandon777]

Right now I have a totally stock 78 sbc 350 with Dana 60 in the back and Dana 44 in the front I will be putting 35s on, sorry I don't have a good deal amount of info

 

[MikeB]

A stock 350 with the addition of a free-flowing exhaust system will usually benefit from a modern cam that has a little more duration than stock.

However, a big-time rumpety-rump cam will kill power everywhere if you don't raise the compression and install intake, heads, and exhaust system that allow for better breathing.

What is the engine RPM at 60 mph in top gear? And what kind of transmission does the truck have? Maybe we can come up with a compromise -- a little lope w/o hurting torque and driveability too much.

 

[MadOgre]

Right now I have a totally stock 78 sbc 350 with Dana 60 in the back and Dana 44 in the front I will be putting 35s on, sorry I don't have a good deal amount of info

8.2 compression

 

[MadOgre]

Headers, aluminum intake, RV cam and a properly operating carb sounds good. Not lopedy lope but as soon as you go off idle with it, it will sound good! And you will feel it right off the line. which will make up for the lack of lope you want

 

[350runner]

x2

Sent from the dust in front of you!

 

[rich weyand]

Yup. A loping idle means the engine isn't set up to run at low rpm, but at high rpm. That's a great setup for a track vehicle, but not for a street vehicle, especially a truck.

Probably the best all around cam for a street vehicle in the low-compression 350s is the Comp Cams 12-230-2. Do not forget to change the lifters at the same time -- that is a must, or the old lifters will eat up the new cam. They need to bed into each other with both new. I would replace springs as well, because the stock springs with a bunch of miles on them will have a hard time following a modern cam profile and you'll float the valves.

 

[Georgeb]

Yup. A loping idle means the engine isn't set up to run at low rpm, but at high rpm. That's a great setup for a track vehicle, but not for a street vehicle, especially a truck.

Probably the best all around cam for a street vehicle in the low-compression 350s is the Comp Cams 12-230-2. Do not forget to change the lifters at the same time -- that is a must, or the old lifters will eat up the new cam. They need to bed into each other with both new. I would replace springs as well, because the stock springs with a bunch of miles on them will have a hard time following a modern cam profile and you'll float the valves.

Ditto to that! I ran that cam in a 327 punched .040 over. It went like a mother even with my vacuum advance set up wrong

 

[Brandon777]

A stock 350 with the addition of a free-flowing exhaust system will usually benefit from a modern cam that has a little more duration than stock.

However, a big-time rumpety-rump cam will kill power everywhere if you don't raise the compression and install intake, heads, and exhaust system that allow for better breathing.

What is the engine RPM at 60 mph in top gear? And what kind of transmission does the truck have? Maybe we can come up with a compromise -- a little lope w/o hurting torque and driveability too much.

I don't have a tachometer so I'm not sure my rpms but I have a th350 transmission

 

[firebane]

Mmmmm 12-300-4 goodness..

Can't wait to get the truck 100% solid and really go take it for a rip.

 

[Brandon777]

I'm also planning to put on a 600 cfm carb, with a high rise intake manifold and headers

 

[firebane]

I'm also planning to put on a 600 cfm carb, with a high rise intake manifold and headers

Just get a good dual plane aluminum intake like the Performer.

 

[MadOgre]

Just get a good dual plane aluminum intake like the Performer.

Because he will be using a 600cfm square bore use the Edelbrock 2701 EPS aluminum intake.

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[Brandon777]

Thanks guys for all your help