Looking to see what I can/should do to an old 305 TBI. It has just under 170,000 miles on it, but it runs pretty well and doesnt leak and doesnt burn enough oil to notice the difference between oil changes. Blows out a little smoke on start up, but I understand that to be very typical of the factory motors as they age.

I'm trying to freshen up this engine so that its at least a little fun to drive (and also lasts) for the next few years while I address other expenses and save up for what will likely be a 350 swap.

Current problems:
1) Exhaust is in shambles and likely in danger of falling off the car. Looks entirely rusted through past the cat.

2) Factory air box is rusty and seems to be flaking rust onto the air filter, making it dirty faster. (not to mention rust in the air intake just scares me)

I was hoping to drop the entire exhaust and put some headers onto it, followed by a fairly OEM style exhaust, maybe expanded a bit.

I was also thinking of installing an open filter element and replace the whole OEM airbox.

I'm also contemplating disabling the AIR/emissions system as detailed in the article on the tech board: https://www.thirdgen.org/serpentine (no emissions testing in my area)


Aside from regular maintence/care any ideas on anything I should to to help extend/improve this motor? Anything I listed a bad idea? Keep in mind that this is a budget build for now...

 

The smoke at start-up is almost always valve stem seals. They can be replaced without taking the heads off of the car. A better type than stock is usually a good idea.

Headers are almost always an improvement.

I'd go dual snorkel before open element.

 

I have almost the exact same setup as you right now:

1991 camaro RS l03, 160K miles,

I'm going to be putting headers on it some time in the next couple of weeks, and I have a set of LB9 heads I may throw on it when I swap the intake, but I started thinking about it, and I might throw a cam in if I pull the heads.



as far as what you're looking at doing, if your going to put headers on it, I would also update the Y-pipe, the factory crush bent tubing is very restrictive, and if you plan to update to a 350, you won't be choking it with a stock Y-pipe.

 

five7kid: Any reason for the dual snorkel advisement over the open element?

ericjon: Absolutely agree about going non-stock on the exhaust, figured i'd hit everything at once from the headers back. Any ideas for a relatively inexpensive setup?

 

a properly setup dual snorkel will is a cold air intake, where as an open element just draws in hot air right off the motor, but it does flow better, but on a 305, you prob wouldn't notice a difference between the two as far as flow goes. I'm going to run a dual snorkel on mine (I'm making one out of two truck aircleaners).

as far as exhaust setups go, I have no Idea there, I'm prob going to make my own, but I'm going to be running longtube headers, not shortys, so I don't have any options for an off the shelf kit.

Goodluck-

Eric

 

Ah, makes sense. I thought I'd read that the open element's flow was more significant, but I can see the point, especially since there's a ton of other flow restrictions on the LO3 to begin with. Might as well be bringing in the cooler air.

 

this is in no way a reliable test, but my butt dyno noticed a bit of an improvement with a 4" open element air filter over the stock single snorkel. noted difference was in engine responsiveness, especially at lower rpms where the stock exhaust wasn't choking it off, and no noticeable difference in top end power. i'm positive a dual snorkel would be a much better option... i'd have built one if i didn't throw out my old single back then