need help . i,m on disability and have limited extra funds for my bird.my question is will i gain any power from removing the cat,emission stuff and installing high flow air filter. emission stuff not needed.car tagged antique no inspection needed . by the way it,s 305 4bbl . everything stock ! THANKS FOR ANY HELP OR SUGGESTIONS ron

 

What I would do is get a high flo Cat(or remove it), headers and a Cat Back exhaust and muffler. Yes, K/N or somthing on the air filter. Gotta watch the K/N due to the oil on the element and contaminating the MAF on some models,

Removing the smog pump and AIR tube won't really gain anything, but if you get the headers, you can get them with or without the AIR tube ports, your choice.

Being limited on funds, you may have to save here and there and install it all at once

 

How much could it cost some kind of good headers + a high flow cat?

thanks

 

See below for my answer...

 

The "best" headers, are ceramic coated and will run $700 for the headers and y-pipe from Dyno Don or Hooker if you do the install. To have a shop install them will run around $400. A good 3" catback will run $500 from magnaflow and will cost about $200 for a shop to install. The cat will run about $150 if I recall when I bought mine.

A high-flow cat from catco won't affect how much your exhaust flows at all. Removing all the emissions stuff might get you 3-5hp.

The headers and catback will free up between 10-20hp.

These two things, the headers and catback will be the most effective means of increasing horse power until you change heads and cam.

For a cam, a Lunati 60102 (60101 is basically a factory replacement) or equivalent from another manufacturer would be a nice upgrade. Remember to swap the springs as well. If you have a roller cam in yours (they started putting them in some 86 models) then the cam will be different as the one listed is for flat-tappet cams.

For heads on a 305, you will want 55cc, 1.94 and 1.5 exhaust. Both World and Trick Flow make decent 305 heads.

However, if you're going to break the motor down far enough for a cam swap, dollar for dollar, it's more economical to swap to a 350.

On a 350, you factory intake, carb and any exhaust you buy (as long as it's 3") will swap strait over (I did it on my 84 T/A).

 

On an LG4 car, headers, 3" cat and 3" cat-back are worth 30hp minimum (could be as high as 40hp).

 

Shop smart and do any and every little thing you can find to gain HP or reduce weight. It all adds up in the.

5 little things that are 3 HP each gain adds up to 15 HP you know.

Taking the smog pump and all off will save weight, and reduce some drag on crankshaft.

Good rules of thumb 100 lbs = 1/10th sec faster in 1/4 mile
10 lbs = the same performance gain as a 1 HP increase in power


true cold air/ram air setup where the carb is sealed and ducted to an outside of car air source is worth 1% power per every 10* f temp drop. It's easy to see close to 100* cooler air outside of car than under the hood. So that could be a 10% gain in power for something you can fab up with scrap sheet metal, $5 poly bucket/pal, alum. cake pan, etc and some dryer ducting.

Do you have the means to do an engine swap? If so do you have $1000 or so budget for it. A vortec 350 with carb would add 100+ HP and with a cam swap and headers would almost double your power.

You can find vortec 350's cheap if you look around. Just on Delaware's craigslist I found these
$550 112K miles http://reading.craigslist.org/pts/5017347648.html
$500 http://binghamton.craigslist.org/pts/5000823027.html
$750 83K miles http://smd.craigslist.org/pts/4991550953.html

Resell the intake, dist., coil, throttle body, acc. drive, etc etc for a couple of hundred bucks

Buy a summit stage 1 vortec intake for $165, mild performance cam for $200-250, intake gasket set for $65, $

All in all after you sell off the un used vortec parts you would have about $900 in the engine. Stock 255 HP, after intake, cam, headers will be around 300 HP

Again for headers. Shop smart. Using Delaware craigslist I found these
$100 shorties with 3" Y pipe http://baltimore.craigslist.org/pts/4998683342.html
$75 summit shorties with Y pipe http://reading.craigslist.org/pts/4990157368.html

 

i removed the cat and air pump , installed a high flow air filter . feel a little better ! saving up for 3 inch exhaust. any other low budget ideas on exhaust ? THANKS EVERYONE FOR YOUR INPUT , VERY HELPFUL

 

Thanks!

I tried to recap with this image I made:



is it correct?

Changing heads and cam is out of planes, I consider it a huge modification. Isn't it?

Is it ok to remove the smog pump? What does it can lead me to?

Night rider327, the two headers you linked, I mean, buying one of them and replacing the stock GTA headers would improve with 5hp a we said before?

thanks!!