What are some good modifications (such as,carburetors,intake manifolds, and cams) to make my 305 scream on the street. I want to make as much horsepower as I can without going over the $1000 spending limit. Any help will be appreciated.

 

Edelbrock Performer intake:100$$
Edelbrock 600CFR:200$$
Summit cam, 204&214W/.420&.444 lift:90$$
headman headers and Y pipe:200
Corvette Toque Converter:1-150$$(available from any transmission shop)
shift kit-20-200$$depending if you want a crummy B&M(I like mine though!) or a good trans-go kit

 

I am going to do true dual exhaust, not a Y-pipe.

 

It would be nice to know what you've got now - year, model, induction, transmission, etc.

The intake and carb are a waste of money, especially on that budget and if you already have a carb. Reasons: 1) Nothing wrong with the CC q-jet, it'll out-flow the above recommended carb, and get better mileage for daily driving; 2) replacing the carb requires replacing the distributor, and that wasn't included in the list and increases the outlay of money, further reducing what you can spend on things you really need; 3) your TCC lockup will not function without the carb/distributor input to the computer, so you need to rig something up to do that. More money to spend, unless you go with a manual switch.

The exhaust is going to cost you. Your "true dual" plan is going to be expensive, and not really worth it on a 305. A good 3" cat-back system (even if you don't use a cat) will cost less and support a 305 just fine.

If you replace the cam but keep the CC-carb (my recommendation, if you hadn't figured that out), go with a slightly more expensive computer-compatible cam. And, replace the valve springs while you're at it. You can do this because you aren't going to waste your money on replacing the carb.

The transmission upgrade suggestions are okay. Except, don't even consider anything other than a TransGo for a TH700 (if that's what you have - again, you didn't say).

That's a good start. To really get it going, you need to do something about the heads - either port your stock pieces, or get some Worlds. But, new heads would bust your budget, and without the other things, wouldn't be worth it. So, port your heads - unless we're talking about an LO3 TBI here. In that case, get some non-swirl port heads and port them instead.

 

I have a Turbo 350 transmission and a carbureted 305 with a Q-Jet. I have changed the carburetor to an Edelbrock 600 one time, but I had to take it back because there was something wrong with the carb, so the distributor doesn't have to be changed. I still want to go the true duals route I can get it done for about $145. I plan to get some headers. I would like to do some work to the heads. How much does porting cost?

 

It is a 1986 Trans Am.

 

Do a search on the exhaust board for No4Njunk, he has duals, but don't exit the rear.


I'd say headers $350.
cam $150 at most
SFCs $100
and maybe a TC.

A home porting kit costs like $40 I think.

 

I didn't price it because I planned on doing it myself. But, I've heard from $120-$200 for a basic bowl blend and gasket match. The Standard Abrasives deluxe porting kit is around $40, but you need a die grinder (I paid $13 for mine at Harbor Freight) and good air compressor to do the job. The heads you have should be good candidates for porting.

If you can get any exhaust work done for $145, you must know somebody. Still think full duals is a waste on a 305, and will most likely reduce ground clearance, but it's your car.

 

I also do not have Computer Controlled carburetor. It is just a regular Quadrajet. Will a Performer manifold be a good performance upgrade instead of the Holley carb? I plan to add headers and a cam to the mix as well. I feel that the true duals is the only way to go as it is a restriction to have a Y-pipe. I also plan on going with a set of World S/R Torquers in the future. What performance (HP/TQ) am I looking at with a Comp Cam (.477/.480 lift), ported World heads, an Edelbrock Performer manifold, and the stock Quadrajet?

 

Also a MSD 6A ignition.

 

MSD 6A is a waste. True duals are a waste. Attack the issues your car really has. Spend your money on things that actually open up existing bottlenecks, instead of throwing it away on things that will accomplish absolutely nothing because the real problems aren't fixed.

Resist the temptation to unbolt easy-to-reach parts up on top of the engine, they will do nothing whatsoever for you. They are not the things that are limiting your engine's performance. Shiny new gadgets up there in plain sight won't make the car go any faster; you need stuff that you can't see.

Your intake is not a restriction until you fix a whole bunch of other things first. Leave it alone. Your carb is fine. A properly designed and sized single exhaust, that fits the car unlike a dual, is plenty.

You have the LG4 I would bet, which has a group of well known problems. The first is exhaust, all the way from the heads to the street. Get a set of application-specific headers and a cat-back for one of these cars, but DO NOT get ANYTHING that will bolt to what you've got; if it fits LG4, you don't want it. Get the parts for something like a 88 TPI 350.

Next problem is the cam. You have a roller motor, so you should get a roller cam for it. I would recommend the Comp "302" grind, XR264HR-12, along with a set of their 1.52 ratio steel roller-tip rockers, timing set, and new valve springs and retainers.

The next bottleneck is your heads. Their ports are tiny, and they have a big step in the bowl right behind the valves. While you ar edoing the cam, pop them off, get them cleaned up, buy yourself a Standard Abrasives porting kit, and follow their instructions carefully. Then get a valve job on them.

After that, you need gears; you have 2.73s now. You should get a posi at the same time if you can; the SLP $99 would be great, but you'll need a set of axles to do that because that carrier is for 28-spline axles but you have 26. 3.42 or 3.73 gears would be best.

Get yourself a dual-snorkel air cleaner from a L69 car. They show up on this site's classifieds all the time. Don't use an open element, the cold-air L69 setup is good for about 10 more HP than sucking in hot underhood air. Big chrome things don't necessarily make more power just because they're big and chrome.

You'll be able to make it through the exhaust, cam and head work for $1000, but that's about as far as that much will take you. However, those 2 mods alone should be good for somewhere near 40-45 HP if done right.

 

Man, I'm sure glad that I "WASTED" all my money on my 305. I guess the Edelbrock Performer intake, Holley 600 VS, Heddman full tube headers going into true dual exhaust with H-pipe, were all stupid investments, and it was just the 3.42 posi rear that put the 86 firebird with 120,000k on the 305 into the 14.80's at the track. Jeez, I guess hind sight is 20/20. And I'm really disappointed cause I got to reuse these parts on the 355 I dropped in a while back, only now it breathes through a Holley 750 VS. I sure hope I can find the old exhaust system, intake, and POS Quadrajunk. Hell the Cobras and Vettes might stand a chance again!!!

 

You haven't "wasted" your money--you are overstating what RB83L69 said.

I'll bet the first thing you changed was the exhaust though, just like everyone says to. And I'll bet the dual exhaust would not give you any better ET than the single 3 inch exhaust everyone recommends on an LG4, either.

Then it is head, intake and cam work, with the QJet (properly modded) providing plenty of oomph.

This was clearly the gyst of RB83L69's post, and almost everyone who has been there will vouch for it, too.