Cam options

[VIKING_MECHANIC]

Since I will need a new cam for the engine(350) I'm building for the 89, I wanted see if there is any semi spicy cams that will play nice with the stock tbi heads or won't require too much modification.

I'm about to start building the engine once the machine shop is done with the components.

Appreciate the help!

 

[sntrym]

I put a Comp XR258HR in my 95 when I did the top end. I was originally going to use Vortec heads but I decided to put AFR 1006 heads on and a 46mm throttle body. The XR258 is old school so you need a new timing cover and a cam button but it provides great top end power with this setup and still gets good mileage. It did require quite a bit of tuning though, and you'll run into that with most any cam you throw in there. If you can upgrade the heads, do it. The TBI heads are trash

 

[L31MaxExpress]

I put a Comp XR258HR in my 95 when I did the top end. I was originally going to use Vortec heads but I decided to put AFR 1006 heads on and a 46mm throttle body. The XR258 is old school so you need a new timing cover and a cam button but it provides great top end power with this setup and still gets good mileage. It did require quite a bit of tuning though, and you'll run into that with most any cam you throw in there. If you can upgrade the heads, do it. The TBI heads are trash

I do not agree with TBI heads being trash for a trucks intended use. Not many choices outperform them from idle-4,500 rpm.

 

[sntrym]

I do not agree with TBI heads being trash for a trucks intended use. Not many choices outperform them from idle-4,500 rpm.

If you use the stock cam they are fine, but almost any air/fuel upgrade along the way is likely going to require other upgrades like a better flowing head. I was able to get around 300hp and 400ft/lbs with the setup I put on, yet still get 16-17mpg at 60-65mph.

 

[L31MaxExpress]

If you use the stock cam they are fine, but almost any air/fuel upgrade along the way is likely going to require other upgrades like a better flowing head. I was able to get around 300hp and 400ft/lbs with the setup I put on, yet still get 16-17mpg at 60-65mph.

I was able to get similar power with the stock heads and 20 mpg @ 70 pushing a brick into the wind. I do not know why you claim that....TBI engines are most restrictive in this order. Exhaust, Cam, Intake Manifold, then TBI.

 

[VIKING_MECHANIC]

So to clarify what I'm after, I'm not seeking Hp or torque increase. I'm wanting something that will give my engine a slight choppy idle - something within the limitations of the stock head and something I don't really have to dick with timing.

 

[Schurkey]

I'm wanting something that will give my engine a slight choppy idle

Choppy idle means misfire.

Misfire means reduced power, increased fuel consumption, and Death To Catalyst(s).

You will not pass emissions testing.

 

[Supercharged111]

Choppy idle means misfire.

Misfire means reduced power, increased fuel consumption, and Death To Catalyst(s).

You will not pass emissions testing.

This. That said, there is such a thing as a meaty idle that is still smooth. I would say my 1500 with the marine cam has a fairly meaty idle around 550RPM with the truck in gear. In P/N it's a more relaxed sounding idle. I didn't choose my setup for sound, I selected what I thought would make gobs of torque. A lopey idle (and its associated duration and overlap) is going to kill you under 2000 RPM and make the truck want to run where the rest of the stock motor doesn't want to be.

 

[Orpedcrow]

Weren’t the “thumpr” and “big mother thumpr” cams designed mostly for sound?

 

[PlayingWithTBI]

Weren’t the “thumpr” and “big mother thumpr” cams designed mostly for sound?

Yeah, early and long exhaust duration, more overlap, and high lift for over 2000 RPM to 6K+. Wouldn't work well with TBI heads and Throttle Body