Another thing, would I really have to change my flywheel? I have a 305 tbi/ t5 combo.

 

You never "need" to change your flywheel, but it can be helpful. If I'm not mistaken, the flywheel that came on the RS weighs 22lbs and the flywheel that is on the IROC-Z and Z/28 weighs 16lbs. So for under $10 and some elbow grease you can free up some of that valuable power lost between the engine and the wheels.
Personally, I'm going to make the swap on my car along with an aluminum driveshaft. The two should be good for 10-20 rwhp and a few pounds

 

Ok cool. What about a 350 vortec flywheel? Know any stats on it? Will it work, do I need to change the starter? do all aluminum driveshafts work?.... With a t5, or do I need a manual car driveshaft? Speaking of t5, I'm not planning to beat on my car constantly, but is there anything I can do to a t5 to make it more, force handling?

 

305 tbi... set of headers, exhaust, 204-214 cam and that's it. you'll get decent gains for the buck but it stops there. the swirl port design of the TBI heads make great low end torque, and great gas mileage. other than that they are not race car heads. i'm not saying don't mod a TBI engine--- because it's fun to zoot stuff up. just dont expect the world out of it.

 

wow what a thread. im glad im not trying to go fast anymore. a simple stock 305 replacement or a stock 350 here. enjoying the 24mpg and smooth running. figure if i wanna go fast ill go to my buddies and grab the big block 91 camaro and go for a spin.

 

Now this is what I don't get- the swirl ports are great for low end torque but the cars came with such high gearing they didn't get to show it off.... *sigh* GM "green engineering"

 

high gears makes it longer to get up which keeps it in its powerband. I would love to get another 305 tbi car and keep it very close to stock for my daily as my current one is just too much gas.

 

i sold the ls1 i had. not just for fuel mileage. but for old school look as well. right now with a worn out 305 im getting 24mpg. i figure all new with underdrive pullies and some hands on tuning ill get even more.

 

advance the timing to +2 degrees, headers, and keep the tall gears. a little bigger cam can help too.

i had an 88 chev 2wd reg cab with an lo3, with headers, a 204-214 cam, and 3:08 gears. it would get 24 mpg (cdn) on the highway. had a similar setup in an 89 with a 350 with similar mileage.

seriously the tbi's were the best trucks on fuel i had. just gutless.

 

True, I did not think about that. What kind of mileage are you getting now, and what killed it the most?

 

the swap i did on here i took my 91 305 tbi and put a 87 350 bored it .030 over and dropped it in my 91 kept the ecu out of the truck that gave me the 350 swapped it and it ran fine never gave me a issue

 

stall converter, bigger fuel pump, and more horsepower cost me the most gas mileage. im still tuning though.

 

...most of the threads I see here tend to be pulled of the topic/highjacked LOL.
I was pretty much puzzled with what to do with 305. Untill I seen S10 for sale at my neighbor's driveway..... dingdingding....
For now I'll probably do the cam and the bbc tbi, header, better manifold thing. After all most of that crap can be re-used on 350 block A-hhhaaaa!!! All that if I have time to do anything at all. If not, I'll just floor it the way it is untill it's dead.
Anywho I've done some extensive (15minutes) searches and came up with this:
1)www.tbichips.com which pretty much has all info, it's too much info on what can be done with 305 TBI to get about 50% more power at 10% of LS1 swap cost (ok, ok, start hating me on numbers....)
2) https://www.thirdgen.org/forums/tbi/...-ultimate.html by Shifty
3) http://www.tbi-superchargers.com/

There. There's all to it. Simple. Enjoy....
No ifs ends or buts. And next time, do yourself a favor before asking for the obvious:
DO YOUR OWN RESEARCH... lazines usualy brings the worst in people on the receving end of one..

 

wow

thanks for all of the information. And here I was thinking the cam, swirl port heads and small bore were the limitations

 

 

i thought ls1s got great gas mileage?

 

yeah my ws6 gets 30-32 mpg pretty easy.

 

^^^ my friend has a ws6 as well, he's getting 30 mpg, with close to 600 to the wheels....(when he doesn't dawg it) he averages 25-28 typically, with hitting 30 now and again

 

All this talk about fuel mileage makes me wonder why everybody is so anxious to buy a 4 or 6 cylinder rice-mobile

 

that has to be a 6 speed?

My 4th gen LT1 4L60E gets 22mpg highway if driven like granny

 

Just located a set of TPI heads not too far from me for $50. Goodbye MPG's!

 

Haha.

 

I mess around with my 305 all the time. Almost everything you do to the motor will work on a 350 if you choose to change it at a later date. My car isnt really anything close to a daily driver anymore but it gets great mileage with the proper tuning and Im not running anything related to emissions smog equipment. Alot of the parts you can use come from other cars and you can be as creative as you want from just reducing the weight to swapping heads and intakes from other GM vehicles and most can be found in junk yards for cheap. I have alot of fun with my 305 and until it blows up for 7k rpm runs ill be keeping it.

 

TPI heads wont give you bad mileage. Not tuning the computer for the new heads will.

 

That is still good mileage. I would say 20 mpg is descent in any car.

 

What do you mean. They came with 273 gears. That is probably better for low end. If you are making most of your torque in the lower rpms , then why do you need a gear like a 342 or 373 that is going to get you into the higher rpms faster? You know those heads make torque down low.

 

I would do a tpi conversion, yes.

 

It wasn't a real serious statement. Theoretically, none of the mods I'm doing will make my MPG's drop below 18 average.


and ninetyone, I know. Wasn't exactly one of my most lucid moments there.

 

that's what i said earlier....some people don't get it. they dream. but dont understand practicallity

 

yes ls1's get great mileage. but there is a cost to go with it. then all the tuning which i can do myself. 500 to start with tuning. but to me it is really nice to see a tbi engine fixed up really well verse an ls1 that people put in everything. sure a tbi engine isnt going to beat a lot of things. but in a preservation stand point ill take it.

 

if that's what you really want then im all for it. but if someone is expecting an 11 second car with 305 tbi not happening unless the car weighs 1000 lbs.

 

Don't know if it's the best thing to revive this thread again, but for those who haven't seen it- this is worth a read.

Articles like this make me wonder why so many hate on the 305. And think about what the numbers would be like with a Hydraulic roller cam and a properly modified and tuned TBI system. Either way we're still seeing at least 300rwhp

http://www.popularhotrodding.com/eng...s/viewall.html

 

it's an awesome article whch shows the potential

now here is where reality and cost/benefit comes into play

are you going to do that to an engine with a tired bottom end? I would hope the answer is no

so, enough said. Why go through the expense when for a few dollars more you get 45 cid more?

imagine the numbers if the test engine had a 4 inch bore?

Look, you have a 305. It is what it is. It's not going to perform like the new 5.0 from Ford nor will it ever perform like a similar modified 350 OHV chevy engine.

It's your car and be happy that you have one. When you can afford a more performance oriented vehicle then do it. That time will be here sooner than you realize.

 

You are certainly right, but a 305 can be a great, streetable engine that gets solid MPG's. And if you're like me and want to keep your stock engine, then it's not a stupid build and some pretty decent power can be made with it. I love my car and don't want it to be like a new 5.0- even though they are certainly faster lol. It's got character.
Even though my car has just over 120k on it, it was very well maintained through its whole life so I have no worries about the bottom end.

Also I've heard that de-stroked, these motors are crazy (summer T-bucket project??).

 

where do you hear this nonsense about destroking?

the destroking craze was during the TA phase of the late 60's early 70's when a 4 inch bore SBC was destroked to become the "legendary" 302 and to meet displacement requirements. (please note that they chose to use a 4 inch bore)

those "wonderous' engines don't even hold a candle to modern technology such as the new five oh.

old school is just that; old school

you have an OHV smog era 305 cid engine. It is what it is. it takes time and money to make that 305 cid perform and the beauty of the SBC is that for just a few dollars more, you can do it with 45 cid more and not need to get as radical to reach the same performance.

The ford and Mopar guys had no such choice because parts interchange were not the same as with the SBC.

there is no value in "keeping the stock engine" unless you plan on some type of complete restoration bringing it back to showroom condition

even then, the market is soft for 3rd gens

do not get all caught up in "the good ole days"

I can take my SCT tuner and without even leaving the comfort of my car I can change the performance of one of my vehicles.

good ole days........pfffttt

 

Sorry, I prefer, as the writers of Motor Trend referred to it- "Vehicular Viagra"