i dont have the money for internals, so all i can afford is boltons....what should i buy to get me there? or atleast close i have an 85 iroc- 305TPI-700R....let me know what i should do to get into the 13's....please help, thanx

NOS

Don't expect any big improvements from any "bolt ons". If a K&N air filter gives you 5hp, you're not going to notice it.

check out my mods below. But there on an L98. I'm going 13.5 now. I'll be going low 13's within a week after i install the Prominator,pullies and afew other things i have planned. It might be alot cheaper to do heads/cam then to do what I have done.

well since you have an 85 IRoc your probably running low 15's I dont know if just bolt ons can get you there but you can certainly make your car pretty quick. Heres what I would reccomend: headers, high flow cat, cat back exhaust, Gut your air box and add K&N filters(if you do a search I am sure you can find a post that explains how to do this),3.42-3.73 gears, and do any weight reduction you can do. Now I dont know if that will get you into the 13's but it will definetly significantly improve the performence of your car. Good Luck.

iroc, thanx....that is what i had planned on doing, but im also doing march underdrive pulleys, and i was thinkin bout the 52mm TB...what do u think bout the bigger TB? also im gonna do the AFPR...and im getting a set of drag radials.....what else should i get ?

I would think that the bigger throttle body would be overkill on a bolt on LB9 your not gonna need it until you change the heads and cam. You migh want to try asking someone on the tpi boards those guys will have all of the answers you need.

I would do the exaust first if I was you.

bolt ons into teh 13's is not really hard depending what you consider a botl on.
my formula would be:
1. gears, at least 3.73's, 4.10's would be better. add a fresh posi unit if you need it.
2. torque convertor and shift kit. you don't have to go too nuts on teh tc to see a major gain from it, something in a 2400-2600 stall speed woudl work nicely for you. for the shift kit, i am a fan of teh trans-go kits. they are pretty easy to install at home.
3. rear suspension = boxed stock control arms, control arm relo brackets, and an aftermarket torque arm(slp/bmr have a nice design that is well priced and an easy bolt on)
4. full exhaust, headers, and a 3inch cat back. go for a cat delete if you think you can get away with it in your area.
5. some sort fo cold air intake, teh stock system is rather restrictive. if you can find an elbow like the firebids used to turn the air inlet 90 degrees you could run it over to the fender area with a cone filter.
another option is to gut the bottoms of teh air boxes and use a few pieces of sheet metal to fab up a ram air of sorts
6. mess around with your shifts. see if maybe holding the car in each gear a little longer helps you down track. nothing nuts, just an extra 500rpm or so. that shoudl allow the engien rpm to fall onto a stronger part of teh power badn after the shift and continue to pull harder.

this is not a promise of 13's, but choosing the right parts will get you a long way towards your goals. as always though, the place to start is by getting to teh track and getting a baseline on teh car. see where you are starting and see what you are up against.

later
tim

Not to be flip or anything, but the best bolton would be to bolt in a 350. I know a lot of guys like to see what they can get out of a 305, but why not start out with a big boost. Im running in the low 13s with boltons, of course Ive bolted on just about every bolt on possible from intake (superram) to exaust (borla catback).

Drag radials can be a big help, cured my spinning problem for a while till I got more motor at least

Nitrous and drag radials for starters.

Time to buy a Mustang, if you want 13s with a few bolt ons, LOL!!!

I think it is possible but one big downfall is the cam. I suggest swapping in something better, maybe some port work on the plenum and runners, bigger TB, full exhaust, gears, TQ Converter, shift kit and some DRs! That should net you some easy 13s!

Depends on the mustang, the SN95's are slow as balls.

Still run 13s with bolt ons!

Also would the car benefit from L98 heads, or are the 305s better? Might be something you can find cheap!

No I dont think the L98 heads would be better, unless they were the aluminum vette L98's. The LB9 heads are pretty good flowing for a 305.

Those heads are really pretty good. I had a pair on my '88 when i had it. Woke my car up alot. Paid $500 for them with 2.02/1.6 valves, K-Motion valve springs, and a 5 angle vavle job. Not bad for $500. Surely you can find a deal like this, or close to it. With all the aftermarket heads available, I see less and less people wanting these heads. Look around for them man, it would be a good deal.

Why do some people just insist on a bigger TB for their 305?

Save your money, you dont need a bigger TB until well after you've hit the 13's

you do not need a ton of power to run 13's, hell you only have to trap around 95mph as long as the gearing and traction are taken care of properly. so don't go nuts or even worry about big money power parts.
for power all you will ned to do is exhaust, CAI of some sort, and free mods.
gears/shift kit/convertor will take care of the rest for you.
it also never hurts to do some minor weight reduction too. you don't need yoru spare tire during a pass, you don't need 80cd's for a 1/4 mile trip, and that 3month pile of McD's wrappers is nasty anyway.

later
tim

Uhhhhhhh am I the only one that noticed this?? 4.10 gears in a Tune port car with stock EFI?? The factory gears that the 85 305 TPI came with are actually a pretty sweet match. On my 85 iroc it had the factory 3.23 gears and a few minor bolt ons and it was DAMN quick. 14.6 @ 95 in 3,200 feet tucson (that corrects to a 14.1 @ 98 which is close to 13's at sea level) and I barely had much done to the car. If you are close to sea level, you won't need nitrous to get into the 13's, but you will need a REALLY good running motor with all the basic upgrades such as the free intake mods, free home ported manifold, regulater, airfoil, exhaust (mine ran that time with stock manifolds tho no headers), and a functional posi!! You'd be suprised how quick you can make the car for cheap if you just port all your factory stuff.

you shoudl try a gear swap, then you will know what 13's feel like. the cars out of the factory have extremely compromised gear selections. it is a plain and simple truth that choosing a gear that alows the engine to run through it's entire power band through every gear you use will be worth a sizable drop in et.
going form 3.08 or 3.23's to a 4.10 gear is consistantly worth .3 to .5 in the 1/4.
gears are most likely teh best bang for the buck et mod you can make, with the right torque convertor being a close second.

later
tim

4.10 areway to much gear for a stock TPI car. The stock TPI only makes power upto around 4500RPMs. If you run 4.10s with stock TPI your going to be slower then you would be with 3.27 1st gear will be very short , then when you shift 2nd you already be almost over reving same goes for ever other gear.It will totally put you over the cars power band.I'm running 3.73 but my car isn't stock. Still only pulls to 5000RPMs with all my mods.

how woudl the car be over reviing? teh shift points are still based on the input shaft speed(the tranny governor controls that) and will not change the actual rpms the tranny shifts at. the speed you are traveling at that rpm will be lower, but if the goal is to run out the 1/4 that is not significant.
since the goal here is to run in teh 13's i will use a generic 13sec trap speed as my example, approx 96 mph will put you solidly into the 13's if you have traction.
96mph in 3rd gear(700R4, 5spd it woudl be 4th gear) with 3.27gears = 4100rpm, this is not taking full advantage of the entire power band of the car. barely getting into teh neighborhood of peak hp is not the way to use the entire power band.
96mph in 3rd gear with 4.10's = 5200rpm, this uses the entire power band through all gears and actually lets the car run a few hundred rpm past peak power(peak power is advertised usually between 4700 and 5000 depending on who's version you are reading).
management of power and getting it to the ground is where et's are made. how many times have you been to the track and seen a car that ran a huge mph but didn't et worth a damn? it is a result of poor parts matching in the drivetrain and chassis 9 times out of 10.
use the power band, use the gear. it is a reasonably low cost and easy way to knock time off at the track.
if you don't believe the rpm ranges i am using jsut look at this link, http://www.f-body.org/gears/ , it is one of the better gear calculators on the web.

later
tim

thats funny that you say 96mph in 3rd gear with 410s =5200rpms. I'm running 13.5s, 3.73s and at 5200RPMs i have trap speed of 101.36 in the top of 3rd gear. See the 4.10 would be slowing you down. a stock TPI car would be past the point it makes power at 5200RPMs. I have after market injection so I pull alittle past 5000RPMs. a stock TPI car will fall on its face after 4700 RPMs. What you dont seem to follow is that stock TPI car makes all there power at lower RPMs. Sometimes more gear can hurt a cars performance.If you want to be shifting at 5200RPMs your going have to have full exaust and after market injection first. Then you might consider a gear change of 3.42 or atmost 3.73s.

aftermarket injection to turn 5200rpm? why would you have to do that? the computer has more than enough tables to run the car to 6000rpm stock. aftermarket injection does not even enter into the equation.
if 3.73's are enough for you to use your entire power bnand through all gears then they are right for you. i do not see how that applies to a 305 with bolt ons, but good for you anyway.
the simple fact is that with mild bolt ons the engines ability to pull past 4700 will be expanded. the power band will easily move up to the 5000mark with exhaust and free intake mods.
tpi makes enough power across a broad enough range to take full advantage of 4.10 gears, 3.73's are not a bad option, but with the example of a 305 with bolt ons the car can achieve more with a bit more gear.
i don't understand why this is so complicated to some people. it is simple logic to say that if you do not use the entire power band of the engine before the end of the track you are leaving et on the table.

later
tim

funny how a guy with a 17sec LG4 is telling me whos going low 13's w/ stock heads and cam and ChrisFormula355 whos going 12.0 that we don't have a clue. I tried to teach you but you dont want to learn. Have fun playing with your online calculators.

funny how the guy you think you are getting smart with has been building adn racing cars for 15years now. jsut because my latest car is an LG4 that i have not modded yet does not exlcude all of the 10second cars i have helped to build.
if you don't understand teh importance of gear selection then you are leaving et on the table, plain and simple. go read up on the NHRA stocker forums and think about it a little, those are the guys that taught me, perhaps you can learn from them too.
ask around the boards as to who i am, i have a lot fo time into these cars adn the respect of many members who go much faster than you.

later
tim

Guys Guys relax. There is no need to argue.
I believe the reason that TPI-Formula350- is saying you need an aftermarket setup is because even with extra bolt ons and porting of the plenuem and manifold the gm tpi system (not computer,but the maifold,plenuem, and runners) were designed for low end torque and it restricts power above 4500 rpms. Thats why you get a different manifold setup like accels or holleys. Its like switching from a dual plain to a single plain. The dual plain is designed for low end power and a single plain is designed for high end, like when you have a bigger cam,stall, etc. So if he has the stock manifold setup all 4.10 gears are gonna do is take him out of his powerband quicker therefore hurting him more than helping him. I am not trying to add fuel to the fire, this is just simply how I understand the system to work. We are all here to lend our advice there is no need for personal attacks. If you dont agree with someone just say you dont agree and forget about it. There is no need to get worked up over words from someone who is *** knows how far away from you on there computer. Lets just take it easy guys.

my view was more to the point of using the gears as another bolt on. that is why i mentioned the intake and exhaust mods.
even at stock or mildly better than stock airflow, teh gears will eb a huge help, certainly better than the stock gearing.

later
tim

the guys that say they are done at 5000 are right on the money,
my buddies car with 383, afr heads, falls on its face with a pile of ecm tuning still over 5000 rpm....the stock intakes are limited, he tried running it higher rpm shift points and went slower, the car dynoes over 400 ft/lbs at the rear wheels....if you have a carbed car like mine that spins 8000 rpm and has everything matched to do so then your 4:10s work, i run 4:10s and come across the line at 7100 rpm.... they are good if your complete set up is gonna work with it...

go with the nitrous...and some sticky tires...thats all it will take .a bigger t/b can actually hurt your lower rpm throttle response....i have done it....
nitrous is your friend....

5000 rpm vs 5200 rpm, is a difference of 200rpm used in teh last hundred feet or so of the track going to hurt the et gain that is made over the previous 1220ft?
the answer is no.
you will gain more in 1220 ft than you will lose in 100ft. that is why you have to use the gears as a part of a complete combo, not jsut by comparing the gears you use to run your motor that spins to 8100 or teh 3.73's you use in your bolt on 350 car.
the car in question is a LB9 with 700R4, the comparisons of many members here based on other build ups are not going to match up to the combo in question.

later
tim

I guess what we're all trying to explain to you is a car with stock TPI is passing the top of its powerband at approx. 4500-4700 RPMs. So shifting at 5200RPMs will be over reving a car with stock TPI by upto 700 RPMs. Thus making your 1/4 mile times slower then if you shifted at say 4500-4700RPMs. TPI is setup for low end power an TQ. Hope this helped ya out....

Period.

i am refering to the rpm that the car will eb coming through the traps and crossing the line, not the shift rpm. perhaps this is actaully where we are not all seeing each others point.
to select proper gearing you have to backwards engineer it from the trap speed and match it to a gear set that allows you to enter the speed trap at the end of the track jsut after you have reved past your peak hp. this allows the car to use the whoel power band and carry every onunce of speed it can through the end of the track.
the shift rpm should be choosen based on where on teh torque curve teh rpm will be landing after the shift. in this example runnign 1st a little further will most likely result in a small gain because of teh huge step between first and second(3.06 1st gear to a 1.63 2nd gear, approx 45% rpm drop), teh 2nd to 3rd split is a lot closer so the shift rpm does not have to be dragged out as far to avoid a little bit of lag after the shift.

later
tim