I've searched and read many posts about building up a 305 LG4 4bbl with the "peanut" cam. Most are for racing or getting as much power as possible without regards to economy.

What kinds of changes to you recommend to gain some more power / economy for a car I will just use as a daily driver on nice days with the T-Tops in the trunk. The car is an 86 with 39k original miles. I don't think there has been any mods. All parts including exhaust look stock.

So far I'm planning on upgrading to the dual-snorkel air cleaner with possibly a catback system as the exhaust pipe is starting to leak. I have already changed belts / hoses, and cleaned the carb. the plugs / wires were changed 5000 miles ago. Do things like intake, headers, and cam really make a difference for a daily driver that will never see a track? I read of 350's getting in the 20's for MPG. i'm getting 17/18 MPG.

Anything else you can think of? Since this is a daily driver should I just give it a good tune up and leave it alone?

 

Check my sig. The last time I checked mileage on the highway, I was getting 24 mpg, which is better than I was doing stock. More power and better mileage with mods. How could you go wrong.

JamesC

 

If you're just looking for a little more 'oomph' when you hit the pedal, I'd recommend a set of headers, y-pipe and a good catback. This will help to get the air out of your LG4, as the stock manifolds and exhaust are very restrictive on this engine. Get a cat-back intended for a 305/350 TPI car, not an LG4. Same for headers.
Your stock intake and carb are plenty sufficient - no need to change those. You may need to tune in the secondary metering rods to keep up with the additional airflow. The dual-snorkel aircleaner is a good step. If you have a mechanical cooling fan, swap it out for an electric one.
If you are really ambitious, maybe swap in a bit larger cam, something with maybe a .420/.442 inch lift (intake/exhaust).

 

I have the Xe256 in my LG4, granted its a Caprice, but still. It's a good cam. Fits under factory specs. Good idle, plenty of vacuum.

 

Not only do you have to let the gases out, you have to let them in.

Do the exhaust as recommended above, but the dual snorkel is also essential.

Cam - Optional, but the XE and Compucam grinds are highly superior to the factory's peanut cam. Mine still idles at 500 RPMs in drive.

 

Thanks for the advice. I briefly looked online at summit and jegs. Not that I have the cash right now, but what brands / models do you guys recommend for a header-back and cat-back? If I am eventually going to replace the entire exhaust should I do it all at once or do you think I do a cat-back first than header and cat?

 

Do it all at once and all for a 305/350 TPI car, that way you get a larger Y-pipe (when it comes to that part). Do you have emissions? That determines header and cat choice.

Hooker makes a great cat back setup. So does Spintech, although, Spintech is a bit more pricey. It's about $120 for their Split Case direct replacement piece i beleive.

 

Hedman Shortie headers and y-pipe $200 for the set.

They aren't the best but they are cheap.

 

Me Leigh, where can u get those headersand Y for that price and do they come with A.I.R.