I know a bunch about the suspension of our cars but the engine work is all new to me. I have a 305 TPI in my 87 IROC and from what I read it was rated at 190 hp and 295 lb/ft from the factory. That seems ok but I was wondering what the best bang for my buck is. I would prefer to get more torque over horsepower but I understand they come hand in hand. So my question is, what mods could I make to get more power out of my engine and how much will that cost? I keep hearing the heads,cam, TPI base and runners would be good things to change, but how much can I expect to gain from that?

 

Best bang for the buck? A 350 long block. The TPI base and runners alone will cost you pretty much the same as you could get a rebuilt 350 for. I don't think the 305 is an ideal choice for making low-end torque, and the TPI intake won't feed it well at high RPM, so it's kind of a lose/lose.

 

numbers mean nuthin with these cars...does it fell powerful to you?..if so that all that matters

 

I hear this alot on here. Alot of people think that the displacement of 350 cis will make more tons more power then a 305. Its not the case.
You mention to buy a 350 long block. If he goes and does that, he will spend, how much? 7- 800 bucks at least( that would be a conservative estimate for stock replacement grade parts. And all he will have is 50 extra cubes, with the same crappy heads, and all the other junk that he had before. And maybe gain 50 hp? and 40 ftlbs

But if he where to spend $1500 and buy a set of good heads and a decent cam he could gain 200+ hp. The heads and the cam is where all the magic is. Look at a "little" 4.8l lr4 gas saver its not even a 305 and it matches the "almighty" 350 tpi's 230hp 330ftlbs with more hp but less torque at 279hp 294ftlbs

Best bang for the buck hands down. NOS

 

depends on the setup but with stock TPI and stock heads, and the stock L98/Lb9 h.o. spec cam, 350 will make alot more power and it shows. My bolt on L98 went 12.90's. GTA matt has gone 12.85 with his L98 with less mods than mine.

havent heard of any 305's getting anywhere near that. its a big difference in power

BUT i do aggree, a proper set of heads/cam/intake on that 305 will make more power than stock heads/cam/stock TPI on that 350 longblock.

May not match allthe torque but it will be close and the 305 will move out well

 

Yeah I know NO2 is the best bang for the buck, but since my little 305 is bone stock with 128,xxx miles on it, I don't think it could handle the NO2.

Would the power from the 350 with cam/heads/and intake make it worth the trouble of swapping out my 305 instead of building it up?

What kind of gains can I expect if I only mod my 305? What kind of heads/cam/intake should I go with? I still want the car to be streetable.

I think CarCraft recently published an article about swapping the iron heads on a 302 for aluminum heads and they gained 92 hp and 43 lb/ft. Is that common or did something out of the ordinary happen with their engine?

 

a 350 with its larger 4 inch bore is leaps and bounds ahead of a 3.73" bore 305

Much better aftermarket parts to choose from with the 350 and you will make LOTS more power depending on the setup.

Depends on your goals tho with the car. with 128K miles, it may not be a great idea to cam/heads that 305.

I'd look into crane powermax 2032 cam, matching springs, for the stock heads and just run that for awhile with a tune and see how you like it. that should net a good increase in power over stock

AFter that, maybe a vortec HSR with vortec heads and that cam with 1.6 rockers will make a nice combo.

But throw that on a 350 you'll have more torque and hp so i'd really look into buying a 350 motor. Even the zz4 crate longblock isnt a bad deal at 3500 bucks or so. Just add intake and accessories, and a better cam

 

It most certainly is the case. Cubic inches makes torque, and the more torque you make, the more calculated horsepower you make. This is an indisputable fact. The only possible exception is boost, and even then, the engine with more cubic inch displacement will always make more, either way you slice it....

 

guys, he asked how to get more torque for his 305. Not if i had a lot of money and wanted to spend it to get the best possible deal for my money wut would i do?... Just let him know how to get more torque from a 305... simple as that...


Also, I feel your research for torqueing up your 305 shouldnt be on this site, everyone here likes to bash 305's if you cant already tell...

 

Nater, it is what it is. Nobody is bashing the 305, but if your asking someone how can I get more torque from the 305, then the answer is simple, more cubic inches. This can be achieved by either stroking the 305 to 335, or simply swapping in a 350 in it's place (which is obviously more feasible). There is a reason why the older 70's engines with 400+ cubic inch displacement were known as torque monsters. More cubic inches will always make more torque, which in turn will always make more calculated horsepower. Think of it as scientific fact, and not 305 bashing....

 

Make what torque you do have more powerful.

Swap your rear gears out for 3.73s or 4.10s. We went from a 3.08 open to a 4.10 posi in our autocross car.

Made coming out of the corners much easier, but at the same time, had to learn not to STOMP on the gas, or we'd just spin out, coming out of the corners on the course.

 

Cubic inches alone is a poor way of making little more torque power, that is an indisputable fact.


If the 305 is choked down with crappy heads, what makes you think that a bigger air pump is going to breath any easier through the same crappy heads.

 

Is it? Try running a camshaft with duration in the 230/230 range, and see which engine is more tolerable, while easily passing emissions. You have to over-cam a 305 to see any real significant power increase, so "a little" isn't going to cut it with an already anemic 305 engine, not to mention what you are compromising by over-camming the smaller engine. Again, unless we're talking about boost, the larger engine always wins when it comes to torque....

The only real way to make a 305 build worthwhile would be by paying attention to all of the variables, and this would include the gearing of the car (both the tranny, and rear), as well as the weight of the car. It would be a complete waste of time trying to get that much power out of a 305 to run in 3500-lb car. More cubic inches allows for more power under the curve, as well as peak, and fourty five additional cubic inches over the 305 is very significant....

Who is talking about the stock heads? How could you possibly desire more torque WITHOUT modding the stock heads. Why not use the STOCK camshaft for that matter, and say you want more horsepower too lol. Either way, the L98 will always make more power. There are guys here running 12's naturally aspirated with the 305, but the 350's were running those numbers for years without even breaking a sweat....

 

Don't know your budget, but if the 305 is in good shape, and I needed to do things in increments, I'd go with a set of 1.625 long tube headers, a 3" intermediate pipe to a either a Dynomax welded race series single in dual out for the factory looking dual exits, or if money was tight a single 3" in and out version. This would support a healthy 355 or larger engine for future builds. Take the plenum off, port it if it hasn't been already and add an adjustable fuel pressure regulator so you can bump the pressure up to compensate for the exhaust and plenum work.

Next would be a cam in the 212/218 -112 spead range. This cam would work fine in a 305 and would do well in a 355 TPI if you went that route later. While the intake was off I'd port the base,, nothing fancy just taking the lip out of the entrance and smooth things out. No need for a throttle body or runners,, the stock ones with a cleaned up base will feed the 305 without problem.

Next I'd look at gears and/or an increased stall speed converter.

Then,,, heads. Here's the delima at this point. You're rather limited on heads for a 305. Probably the best bang for the buck are the vortecs, but the Vortec TPI base you would need to run these heads is rather expense. Heads and base would put you out about $1000. Trick Flow has a set of "305" heads, but the flow numbers on them are only marginally better than the Vortecs,,, and the stock intake would more than likely put you at about the same place you would be with the Vortec combo.

So,,, before buying the heads, I'd take a long hard look at swapping the short block to a 355. You do that,, and later you can add a set of 195 Canfields for around $1000 (that flows about like the older version of the AFR heads) and you could run the stock base. A 355 with the stock base and 195 Canfields would out perform a set of Vortecs and Vortec base. If you went 355 and Canfields,, next step would be the FIRST Injections TPI system. Intake, runners, plenum, throttle body, fuel rails all for $1000 which is a good price for all that. It's not a direct bolt on, you'll need to get a stand-alone AFPR and run fuel lines to and from it,, but it's not all that hard to install.

So,, if you think you might swap out to a 355 later,, I'd do it before buying heads. If your long range goal is more cubes,, that's the way to go. You build in increments and you'll know if more is never enough and the cube bug bites. However, if you're set on running the 305 while it is still working fine,, I think I'd go with the Vortec combo, and swap the runners and throttle body when and if you ever go with a larger engine.

 

Seems like everyone thinks my poor little 305 is a lost cause...

I know I asked how to build up my 305 but I'm still open to all suggestions. I also know the 305 is the ugly duckling when it comes to making power with a V8. My motor runs fine the way it is so I guess I'll just leave it alone and focus on my suspension rebuild (I autocross). Then later down the road (probably after college... still a junior in high school ) I hope to drop in a 383 or something.

 

simple bolt ons for now will increase power but dont expect a whole lot. maybe 2-3 tenths of 1/4 mile performance with intake mods and better exhaust.

 

to actually try and answer youre question, to make " more tq" the to do list would be the same as on any other motor. basic bolt on's. a good free flowing exhaust from headers to tips is the best start, that and a afpr with a bump in the fuel can give you up 20ft pds of more tq. match it with the proper cam and intake and u can more than double that. and more importantly get all youre tq to the ground with a built tranny, gears, and suspension. and you should have a nice jump in overall performance.. i have lots of bolt on's on my "anemic" 305, and trust me, it makes torque!!!! 1st gear is pretty much useless. i want more tq so im strapping on a supercharger right now, and when the 305 blows a 355 will be built with all the stuff from the 305 block.. pretty torquey id say..

 

Not to start a whole big thing with you, cuz I happen like you, but what do you consider "making torque"? Are you pulling at least 300 pound feet of torque to the wheels in the power band? Cuz if your not, then your not making torque. Yes, if your going to compare the anemic 305, to say, a 2.8/3.1, then yes, it does make more than enough torque (for what it is). Torque is PULLING power, not SOTP power. Come on over one friday night here at the track, and we'll gladly embillish on the true principle behind torque for ya....

It's not a lost cause, it's just not worth the investment....

Now your talking! A 383 in comparison to a 305 is literally a night to day comparison. If you want to build up your 305, I would say go for it! We all made similar mistakes over the years, which is why you'll get a lot of us telling you to go the 350 route, cuz we don't want to see you newer guys, who are first starting out with their builds, making the same mistakes. Whatever you do to the 305, make sure it'll benefit the 383, since it's all inter-changeable. However, just don't spend that much money on the camshaft. If you want a cam for the 305, go with a used (but good) LT1 camshaft. When you get the 383 in there, then you can delve into the newer lobe designs that provide an unbelievable amount of power under the curve, while stretching that power all the way up....

 

hey street, thanx 4 not beating up my reply.. anyways i would have to assume that im making at least 300tq to the wheels with my mods.. whats youre opinion?? ive seen up to 500tq, but realisticlly id like to make 425tq to the rear wheels after the procharger goes in, and i get tuned. ive done many hours of searching on here to come up with those numbers. its been done more than a few times with boost and the supporting mods. read my long annoying sig, and let me know

 

^ I don't think your making 300 pound feet of torque to the wheels with just the Crane Cam; 270/276 .452/.465. Do you have any work done to the heads in conjunction with the cam, as static/dynamic compression will help paint a better picture, overall. Other than the cam, most of the other aftermarket parts you have are designed to allow the engine to run much more efficient, launch very well, as well as some very good suspension mods to boot....

Try to make it out to Englishtown this Friday night, as the weather is supposed to be excellent (70-75 degrees). Bring your helmet, as we can have you run shotgun with a few guys running in the tens. My man Paulie just made some upgrades to his Grand National, and from what I'm told, it now pulls like a raped freaking ape, and he was already running mid tens, Click here....

-Rob

 

stock heads,, and the lift a bit more than that with the 1.6rr's its right up around 500, there's a good sale on some 113 vette heads here, hot tanked, magnafluxed, ect.. new springs i might buy them and put them on with the supercharger. there a good investment, thed also work good on a fresh l98..

 

Mileage doesn't mean anything, it depends on how well the car has been taken car of. My car has the same amount of miles as yours and takes a floggin every Thursday at the strip on a 75 shot. The motor has the same compression now as it did 4 months and about 5 bottles ago. A good tune up and premium gas is all you need to do.

Just remember, nitrous is hard on a motor, and $50 bottle fills don't go too far. They usually last me about 10 passes, 1/8th mile. If you run it hard a lot, go for bolt ons. I believe the 2400 stall converter helped my car out the most e/t wise.