Hey guys. I've been debating on what to do for more performance while I collect parts for my ls swap. I went from a h/c 460rwhp ls to a completely stock 305 5 speed so you can image what I'm going through lol. I thought about a lt1 swap (cheap) and a 350 swap. Then I thought why do that and waste money? So here's my plan. Port the tpi set up this winter (gotta do a intake gasket anyway) and a catback. I can reuse the catback with the ls swap ,porting the intake is free as I have all the tools. Also going to remove the smog pump,air and egr. My friend is also going to tune the car.

The only thing I'm in the fence about is 3.42s. Do 3.42s make that much of a difference in a 305 tpi 5 speed set up?

I'm also thinking about picking up some cheap Shorty headers.

So here's the break down
3.42
Ported tpi
Catback
Shorty headers
Tune
stock otherwise

What kind of boost in performance can I expect with these mods? Can it be a high 13 sec car?

I'm a noon with tpi and SBC. Thanks

Maybe an air foil and k&n's.

 

Ha ha those mods won't make your 305 feel like 460rwhp but 305/5-speed cars with the L98 style cam and G92 gears are no joke and nothing to laugh at in the hands of the right driver.

That's important to know - does your car have the L98 style cam? The highest performance LB9's were paired with the T-5 and 3.42 gears (10 bolt rear) or 3.45 gears (Borg Warner 9 bolt rear) and posi-traction. If your car is late year model year production 1989 - 1992 hopefully you have the N10 dual cat option.

TPI cars in general I have found perform best when an entire system is upgraded. The best bang for the buck I got was installing headers on my car. I installed hooker headers, a single 3'' high flow cat and flowmaster 3'' after cat exhaust. I got some gains from the new cat and flowmaster set up but my car changed a lot when I got the headers put on. That was when my intake was all stock too. All of the exhaust work should at least be worth 20hp and 20 pound feet of torque.

While you have the intake off do all the mods that you can afford at that time. Porting the plenum, high flow intake runners, and high flow after market base will help out to. Should roughly be worth 20 pound feet of torque and 15hp on a stock head / stock cam motor.

Also consider putting a ram air system on your car. The TPI Camaros are blessed because most of the air coming into the engine comes from right behind the fog lights. Hawks Thirdgen has some ram air boxes that work well for this modification. Take the base of the TPI airbox and cut out all the baffles. You just want to have the filters sitting in the housing with nothing below them. Then the air boxes get screwed to the bottom of the TPI airbox. This creates a ram-air set up as all the air that passes through the fog light area will get directed smoothly to the airfilters. I don't konw how much power this is worth but it made a difference to me in terms of acceleration through out the entire rev-range.

Install some subframe connectors and think about other suspension items such as bushings, shocks, boxed rear control arms, track bar, etc. Make sure you have good tires on your car too. Making power means nothing if you can't get it to the ground properly.

Yes with those basic mods and good traction you should be able to get the car in the low 14 second to high 13 second range in the 1/4 mile.

Your trans and clutch need to be in good shape to. The newest of our cars are from 1992 so now the 'newest' cars are 20 years old now. Just some things to check on all of our cars since they have all hit the 20 year or older mark now.

Your motor needs to be in good shape too. If it has a lot of miles and it's time for a rebuilt don't expect the same level of performance from a 200,000 mile motor that you would from a 50,000 mile motor. 305's and 350's can go for a long while and take a lot of abuse but, maintenance and care play a role to as I am sure you know.

 

It only has one cat and 3.08 gears. I saw those air boxes from hawks, not spending 300 but I may make my own. The motor only has 70xxx so I'm not going to due any internal work and its runs awesome. I'm going to dyno it before winter on the same mustang my ls1 put down 460.

 

Yeah making your own wouldn't cost that much and you would get some real gains too. No at 70,000 miles you are good to go in the engine department. Even if you don't switch to the L98 cam you may want to put on some 1.6 ratio rockers to get some extra lift out of the peanut LB9 cam.

After you do the intake and exhaust work you may want to get in to the motor, just depends on what you want to do. At any rate after all those mods you will have a strong running LB9.

 

I just wanna get a little more pep out of while I built the lsx. How much power would the 1.6 rockers add? Roller I assume? dumb question but can I change the cam with the heads on. IR do I need to pull the heads for a cam swap?

 

No you don't need to pull the heads for a cam swap. The 1.6 rockers should add around 12hp-15hp.

 

The single biggest "seat of the pants" mod youve listed will be the gear swap all the other free and or cheap mods you do will add up to very little in so far as what you will feel driving it, but gears will put a smile on your face. I went from 3:08 to 4:11's on mine and it was a far more noticeable improvement than when i changed the cam,base,runners,and heads. And even with the 4:11's and the 5 speed i'm still getting 25mpg on the highway