How fast can modified dailydriver 305 with ultimate tbi be?
Any chance to go mid 14's and still be daily driver?
Does it make huge difference if it was 350?
What is potential rpb range for these engines? How much worse tbi is than tpi? Or is it worse in overall ranking (fuel milage, hp, reliability etc)?
Just interested since i will have to rebuilt my engine and of course i want it to be faster, still reliable as my current 305 tbi is and not a gas-o-holic.

 

the TPI can support more HP but the TBI is lower cost to modify. check out intake cost for TPI manifolds as well as TPI injector costs. there is no substitue for cubic inches. if you were to modify a 350 engine there are more options and lower cost due to competition.

 

im running 14.791 with the mods in my sig...this week i plan on installing a ProBuilt Street/Strip tranny and ACT 9.5" 2400 stall torque converter and if it doesnt rain sunday ill be going to the track, so hopefully i will have some new and better times then.

 

I ran 14.48 @ 96 mph with a 305 TBI and stock heads. Search for my name and 305 dyno numbers. Drove it everyday for ar until I got my 350 TPI back. I believe with cheap heads (~$500-600) and decent tuning you can get 13s with a TBI 305.

 

Stock TPI vs stock TBI have the same potential IMO. Stock TPI sucks, MPFI(multi-port fuel-injection) is good. If you consider MPFI, got aftermarket (Stealthram ,superram, LT1 modified,mini-ram) and get a custom chip. You WILL need a need fuel pump for a high pressure system ($120) + $200+ labor for MPFI.

 

My stock interanally 305 was only good for low 15s, and that was with alot of tuning.
Yes, it's noticeably easier to go faster with a 350.
The RPM range is what you design it to be, for a streeter, doing less then 6K RPM there's no worries.
TPI done right can generate a lil more HP, but, it's alot more expensive to build. TBI can also take alot more tinkering with to get it to run it's best. Either can be done well, I have TBI in my truck that I've tuned some, and Port in my car, and both drive alot better then any stocker ever thought of, but both have a fair amount of tuning in them.
Gas mileage is about the combo, and tuning. I got 23-25 with a 13 sec TBI car.

 

here's a post i just put up on the status of my 305 tbi project.

if i'm not in the 14s yet, i believe i will be when i do the intake and chip tuning.

i hope to get well into the 13s when i do heads and cam. it depends on how long the 305 holds up. it's in great shape, so i want to get what i can out of it, but i'll never put money into that shortblock if it pukes.

read everything you can on here. there's a lot of great info. as you learn, make notes to yourself and begin to plan your combination.

post -----------------------------------------

the sig is where i was before header/exhaust install.

went against conventional wisdom, and i think i may have hit a small jackpot.

went with slp 1 3/4" headers (w/ air tubes)

dual 2 1/2" cats

awesome custom mandrel-bent y-pipe and 3" cat(s) back.

flowmaster muffler and dual 2 1/2" tailpipes tucked up under the car.

the stock 02 sensor works fine, it idles at 600rpm, and is actually quieter than before (and it's the same muffler!).

more importantly, i'm not experiencing any of the bottom end torque loss i feared with the big tube headers and more free-flowing exhaust.

i have a serious wheelspin problem now where it bogged before. get best 60' times by launching at around 1,500 rpm, waiting till the tires hook, then nailing it. still only in the 2.3-2.4 range. there's a lot more et improvement in lowering those 60' times.

times on the g-tech have varied from 15.30s all the way down to several 14.90 runs. prior to doing the headers, i ran the car down the dragstrip and on the g-tech simultaneously. it was close. the car feels a lot faster now, i think the g-tech is pretty accurate.

comparing the tach to the g-tech memory shows my factory tach to be right at 500 rpm slow. i've gotten my best times shifting at 4000 on the tach. the g-tech memory shows the actual shift point to be at 4500. winding it higher makes it slower.

i'm taking the car to the dyno thursday night to see what the hp/torque changes are. won't be able to get real track times on the car till january. : (


SECRETS TO GETTING ACCURATE G-TECH TIMES:

1. accurate weight. I weighed my car with a full tank of gas and me in it ... 3775lbs (i weigh 275)

2. did the g-tech setup inside, on a flat table, with a level. it corrects to .00, .01 now in the car

3. set rollout to zero. there's a section on rollout in the manual. it makes it clear that the more rollout you set on the unit, the faster the times will be.