I'm driving a 1986 Firebird. It's a 305 4-barrel 5-speed, H-code in the vin.

Any tips would be appreciated. I would like to get a more power than I have, but I'm not looking to build a really high performance ride. Just a little more 'oomph'. I've read through some of the forum, and alot of you seem to know these cars like the back of your own hand, so any help is appreciated.

Where would be the best place to order the rebuild kit? Carb- brand suggestions for this model, cfm? Intake? Cam? Heads- new, or modify the stock heads? Anything else?

Thank you so much for your time.

 

carb is on top and easy to get to, but won't net you any HP. Go for HP, not ease of work

Start with exhaust. Headers, y-pipe, cat-back. All of it, replace it all.
Then look at getting a dual snorkle air cleaner
Then see about subframe connectors for your car
Then look at a camshaft, and porting the heads

 

Thanks. I'm having some problem with the exhaust anyway, so I had planned on a good system. The reason I mentioned the carb was because the stock carb needs a rebuild, and I'd rather just buy an upgrade. Any one else?

 

well im not a big carb fanatic but id say bump it up to an aftermarket unit, as far as the rest goes, he had it right with the exhaust, cam and head porting, id say change out the stamped rockers for some rollers but some people dont like em, they free up friction in the valve train which some would argue give more HP. Makes sense to me

Keep in mind if you put more "oomph" into it you may wanna upgrade the suspension, brakes etc, and possibly switch to a limitted slip rear. but those are of course down the road lol subframe connectors definitely help the handling of our cars becuase of the notorius flex in the frame lol some eibach springs if you like the look of a lower than stock fbody would be cool too

Theres endless possibilities to these cars

 

Nothing gives you more bang for the buck than long tube headers, but if you dont want to lift the motor go with short tubes. I have a 650 cfm holley 4165, which I believe is the perfect carb for these motors unless they are highly modified. For a carb rebuild kit i'd find what you want at summitracing or jegs, then find the same product on ebay, (i saved $10!).

 

Rebuild the carb.
Swapping to an aftermarket one brings all kinds of hassles into the game. Converting to non-cc, converting to non-cc distributor to match, needing a squarebore intake, or using a spreadbore aftermarket carb (then what are you really gaining?), etc. Just rebuild the stock carb.

Long tube headers require custom exhaust = huge PITA and $$$$. Short tubes mean you can use an aftermarket y-pipe and connect it to your normal exhaust. hooker 2460 I think is one of the good ones.

 

well really a well tuned quadrajet to me, is better than after market anyways

 

I think the options were ground down pretty well in this thread:

https://www.thirdgen.org/forums/carb...tions-lg4.html

 

sofa's advice in that thread is GOLDEN. Read it and re-read it, it's good stuff.

 

Especially that part about swapping in an electric fan and the guy who has saved all that gas money with the mileage increase these past few years. I heard he drove to Missouri and back this past summer (850 miles one way) and averaged better than 27.

 

You all are a big help. I'm newly married, and my wife has agreed to let me do all this as a wedding gift. Haha. Can't beat that.

 

congrates rmabe_85 on the marrage. and thats one hell of a wedding gift! lets see... you want more oomph but you don't want to complete street pro it. understandable. but not as much fun lol. now, i agree with the guys that want to go with the aftermarket carb, i did, and it wasn't any hassle, frankly i thought it was easier, well, i guess it wasn't anything special though. the intake manifold is just about the easiest thing possible to do in my opinion. get a high rise or dual place intake manifold, stealth ram has good ones, some people swear by the edelbrock performer RPM dual plane, others say weland (its what i go, its alright). depends on your money preference. so i say, get the carburator, the intake manifold, and headers (sonix opinion about the headers is the best i think). The intake manifold will open up a somewhat high RPM range, the carburator will just make sure your getting fuel etc etc, and the headers will make sure no power goes unwasted. (they can free up alot of HP). Now, if you want to get a little more techinical and a LOT more power here what you could do. you can get aftermarket bolt on heads that can add from 40-70HP, sometimes more on 350's i know, i'm not real familar with the 305 but i got the basics. anyway, the heads will give you a ton more air flow and a higher RPM power band, but all this mainly depends on the camshaft, and the thing is, you get heads, you need a good camshaft. i've heard talk about the zz4, i think its for the 305 and its got some bad A$$ lift and duration specs for a 305. now, some people don't like roller rocker arms, but i think they are simple, you just might have to get some bigger shinnier =D valve covers to go with them, depending on the ratio, 1.6 high end is always nice, more lift, more air, more fuel, more power. now the subframe connecters are definatly nice, but if you go with doing the heads and cam etc etc, you'll be getting a fair amount of power, so a suspension rework is recommended, unless you want a great burnout machine that is. torque arms, lower control arms, swaybars, panhard bars, springs/struts/shocks etc. it really depends on the amount of money your wife will let you spend lol, i'm kinda going all out here, sorry i'm having fun. with a 305 its not recomended to do anything with the bottom end, its just a waste of money, if your going to do that you might as well drop a 350 in it, its cheaper, and the power gains are alot greater.
like some people said above, you could just CNC port and polish the stock heads you have, but personally its better to get new heads that are CNC ported and polished with a great modified valve train. tell me what you want and i could even set you up with links to sites with prices and specs and estimated HP and TQ gain, just say it and i'll do it =D, hope to hear from you soon.


edit: whoa, i didn't know i wrote that much =D, sorry for the novel, but i was on a roll, my bad

 

As linked in the linked thread above, https://www.thirdgen.org/forums/faq-...5-engines.html . In the "FAQ" forum, no less.

Even though this is a "gift", don't waste money on things that don't improve performance. Please don't fall for the "aftermarket carb" stuff. Rebuild yours or get one rebuilt (I happen to have an extra sitting around, another member said he wanted it but then backed out).

sofa listed the "don'ts" pretty eloquently. The engine is my sig was basically the same when it was a 305.

(For the record, the ZZ4 is a GM 350 crate engine. The cam will only work in a factory roller lifter block. '86 will not have a factory roller block.)