Best mods for 305 TBI
 

Ok so far ive installed on my 305 TBI w/ 9,000 miles i have:

3" Hooker Super Competition Longtube Headers w/ full 3" exhaust

Flowmaster 80 Series

Accel Super Stock Yellow 8mm Wires and U-Groove Platnium plugs

Accel High Perf. Distributor Cap and Rotor

Edelbrock Chrome Air Cover w/ K&N 4" round filter

Transpack Shift Kit for my TH 700R4

Catyalatic Converter Delete


I plan on doing a B&K Under drive Pulley 3 peice kit, Hypertech Theromaster Chip w/ 160 degree thermostat, possibly a new Edelbrock TBI intake manifold. My question is, what other upgrades would you reccomend i do to get the most hp out of my engine before i start to do "internal" upgrades? Im on a tight budget and have been looking for the best yet inexspensive upgrades. Any suggestions? I do plan on putting a Magnaflow High Flow 3" Cat back on the car but will i lose hp doing that or will my engine perform better putting on back on. I can notice alot of black soot buildup on my rear bumper after i was it then drive for a few miles so thats the biggest reason on putting one back on especially after the car gets painted in a few weeks. But is there any more inexspensive or free mods i can do my engine to give it a lil more umph or "get go"? I also plan on a A/C delete and Smog pump pulley delete later this spring. Any imput is apprecitated!

Re: Best mods for 305 TBI
 

:lol: I have a friend that just installed them a few weeks ago, we suppose hp went up somewere between 0.1 - 1.5 hp because dosent make any difference.

0 hp gains + bad miles per gallon

0 hp gains

Loocks like you can save some $ and time.

Re: Best mods for 305 TBI
 

Im guessing with what i have installed right now im at least around 200-205 hp. The car comes stock at 170. But the smog pump and ac delete are going to happen anyway because neither work so it will just save me time to take them off now and it will save me some weight. I was told that the chip will help because yes you are only running at 160, but the computer will read the sensors as the engine is still cold so it will dump more fuel which will produce more hp and yes it will get crappy gas milage, but the car is only going to be a street/strip car so it wont get driven everyday like it is now.

Re: Best mods for 305 TBI
 

A good tune to take advantage of your exhaust is a good idea.

Lowering thermostat ° without fan switch sensor ° doesent make sense.

A good tune, 180° thermostat, 200-210° on/off fan switch and cold air intake is what tbi likes in hot conditions. Basicly a rather hot engine with fresh air.

Yust for your own science (doesent have to be expensive and good loocking), feed plenty of fresh air to your engine when its healty hot and then do the 160° hipertek mod for comparison.

Re: Best mods for 305 TBI
 

Im still looking for a cam that i can run that will still work with my stock ecm. I was told an Edelbrock Rolling Thunder would work. But i was also looking at a Comp Cam Xtreme Energy Camshaft and my dad told me i could run that cam with my stock heads as long as i ran new springs, but i wouldnt be gettin the optimum performance out of my cam unless i tuned it with a flashed ecm. is this true?

Re: Best mods for 305 TBI
 

save the money on the hypercrap chip, and buy your own hardware to burn you own chips. its been proven that the hypertech chip basically adds timing, and not much else. i think it works out to about the same amount of money.

Re: Best mods for 305 TBI
 

sounds good. any recommendations about a cam?

Re: Best mods for 305 TBI
 

I think we are able to put 305 (Lb9) heads on our LO3's. Maybe someone can add to this and clear it up some but I believe that there are gains to be seen in doing that.

Re: Best mods for 305 TBI
 

For a cam, many will suggest a LT1 cam, when it's time for me ill go a little warmer then a LT1 and get something that will give me a little chop in the idle :o) Not at that point yet so there is nothing really I can add to a cam choice.

Re: Best mods for 305 TBI
 

I do have Lb9 heads in the garage but i was told that there wouldnt be much of a difference between the 2 sets.

And can i run an LT1 cam in my car without having to replace my ecm or re tune it?

Re: Best mods for 305 TBI
 

No dont try that. Hypertech is a waste of $, dont go with the edlebrock tbi manifold, go with the carb manifold and an adapter, I say this because the tbi manifolds bores are 43mm, your stock tbi is about 46mm, somewhat of a restriction to be honest, and you wont notice a difference. Dont waste money on the underdrive bull, go buy a 50'' belt, get rid of the smog and a/c if you can or want to, you will notice a difference. That mod alone dropped my old lo3 0-60mph from 8.49 to 8.24. If you want to go with a 160 thermo it is a good idea but you WILL need a chip. Cooler engine=longer lasting and better breathing. The fan switch is helps alot, especially in traffic.LB9s are a solid 10hp.

Re: Best mods for 305 TBI
 

sounds good. What kind of chip would you reccomend running if i was to get a 160 thermo. Ill look into getting a carb manifold w/ an adapter. I just purchused a throttle body spacer off ebay for bout 35 bucks.

Re: Best mods for 305 TBI
 

You can use the Edelbrock TBI manifold and it make a differance, just get the holes bored out to 50mm. yes it works, ask me how I know. As far as underdrive pullies they do work as well but if your willing to spend the money get the WHOLE kit not just the pullies. It will free up ALOT of room on the front of your engine plus remove a good bit of weight as well.

Re: Best mods for 305 TBI
 

I'm sorry but that is just bad information. Fuel injected engines have no business running that cold. It has been proven that an engine that runs at 160° lives shorter and has more uneven cylinder wear than one that runs at 200°. And temperature has affect on how well the engine breathes, you must have meant something else. Fuel injected engines run more efficient at hotter temps than their older carbureted bretheren. This is why all new cars run between 212° and 220°. HOT! Like thomas1976 said a 180° thermo with a 200-212° fan switch is a nice combo for a TBI engine, no colder. With a custom tune to match! Not an off-the-shelf scam chip.

It has been widely debated weather the TPI heads are better than the TBI, and I doubt LB9s are an automatic 10hp without port work and/or a tune to go with it. I think Fast355 has proven that the L30 059 heads are a premium choice for a hot 305. I have some 416 heads (LB9/L69) heads that I was going to use for my 305, but now I am thinking 059 heads.

Re: Best mods for 305 TBI
 

I have a chip from my old TBI computer I got off Ebay a while back cant remember what it cost me but it help me out alot, I ran a 15.20 with everything you have minus the headers, and I have 373's and I did the ultimate TBI mod on this site I will sell it to you for 15 shipped if you want to try it, and of corse that was befor the lt1 and t56

Re: Best mods for 305 TBI
 

ya im interested.. Can you send some pics to JSimba711@NetZero.com.

Re: Best mods for 305 TBI
 

yes L69 heads do give more power. higher compression :) They do work well for TBI. Lets be honest though all that $ could go towards an LTx and you would hit 300hp pretty easy and still get ~20 mpg. I have a 305 too but refuse to mod b/c of the 350 option.

Re: Best mods for 305 TBI
 

i only plan on doing small monds just to gimme what i can out of the 305 for now until it takes a **** on me. Then i have a 383 stroker pushing almost 500hp all motor in the garage waiting to go in something. I also would like to put the T5 in my car that sitting in my totaled formula. But ill just do what i can for now till later down the line i can afford something bigger like the engine swap.
----------

I have 2 edelbrock carberated manifolds in the garage. 1 came on the 383 when we got it and its a Tourqer? Is that any good of just plain crap? Then we also have another one but im not sure what model. id have to take a look so i can already save myself money there and dont have to buy another manifold.

Re: Best mods for 305 TBI
 

I will get those for you today sometime. I did the exact samething and was getting 20 mpg on the highway with those mods

Re: Best mods for 305 TBI
 

haha must be nice. rite about now i can only go 210 miles on a full tank.... it sucks ***....gunna run some sea foam and clean up the injectors and replace the fuel filter today. sounds good to me man...

Re: Best mods for 305 TBI
 

L69 heads will give you the SAME EXACT compression ratio of the current engine. They also have a poorly designed combustion chamber that will not make the same power your current TBI heads will.

LTx is a pain in the rear. The 305 could EASILY make 300 HP from the stock shortblock. ZZ4 heads, a nice cam upgrade, single plane intake, and EBL controlling things.

Re: Best mods for 305 TBI
 

I remember being told that the L69 heads are also just as bad as mine and wont help that much, but im going to start looking into EBL tuning.