Tchaney86

I'm rebuilding my 305 engine. I have no idea what to buy, and from where. I want to try to keep it under $1,000 but get alot of horsepower out of it. Please help!!

dankhound

Nitrous oxide

ME Leigh

Why are you rebuilding your 305. You can barely do a stock rebuild for $1000. Your not going to make any hp at all.

si_camaro

Welcome to the boards. You're opening up a huge can of worms with that question, don't be surprised to find a lot of posts telling you to ditch the 305 in favour of a 350. You'll get more power for your Dollar with one, it's no joke.

If you're set on boosting the 305, look up a member called Sitting Bull. He has a good setup on his 305, and last I checked he is around the 300hp area.

Hope you find what you are looking for,

Si

cali92RS

Dude you should browse through the board and actually read some posts before posting. I bet you there are about 20 "make my 305 fast" posts. You dont even need to do a search, they are always up.

Cadillac

I was one of those 20 not long ago.

Start on the TBI or TPI forum depending on what your engine is... go from there. If you have a TBI like me here's what I would do:

• Open Air Element: Cheapest first thing you should do.
• Headers: I have no idea what kind but others in the aforementioned forums will.
• Camshaft: Again, same forum experts will be able to give you the scoop.
• Exhaust. Let it breathe!
• NO2: Be a lauging gas speedster!
• Much more...

I think the most I saw someone with a 305 getting was 325 HP. Check out this link:

305 to 325 HP.

I'm just shooting for 200 HP and an efficient engine. 300 HP in my car would kill me.



Have fun with it, eh?

five7kid

iTrader: (14)

What I spent 3 years ago:

World Products S/R Torquer 305 heads, with upgrades springs, unassembled - $700. I then got the Standard Abrasives Deluxe Porting Kit and a couple of carbide bits, pneumatic die grinder, for about $50. You could port your 305 heads, depending upon which 305 you actually have, but you'd still need to install 1.94" intake valves, have the intake seats opened up to 1.94", install screw-in rocker studs or pin the press-in studs, and get upgraded valve springs & retainers. End cost is almost the same as buying the World heads.

Hooker 2055 headers, Catco 3" univeral cat, Pacesetter cat-back, replaced the Pacesetter muffler with a Flowmaster, and some odds & ends to get the universal cat in the system (direct fit would have been cheaper) - almost $700 then, probably more now.

Crane 2050 Compucam and lifters, timing set - around $200.

Take-off GMPP ZZ3 intake manifold - $75.

Take-off ZZ4 oil pump, oil pan, & baffle/main studs - $40.

Various gaskets - $100.

L69 dual snorkel air cleaner (used), hoses & scoops - $175.

Restalled torque converter - $125.

Shift kit and what it took to get it in and running again - $150.

All of that without "rebuilding" the 305. Desktop Dyno says 362 HP @ 6000 RPMs, calculated using dragstrip data says 245 rear wheel HP.

You can see my recent post about "305 lovers" for the 305 vs. 350 thing.

$1000 is almost enough to handle the exhaust and air cleaner. Of course, we still don't know what car you have, exactly.

Nate86

ME Leigh is right. You won't be making "alot of horsepower" with only $1000 for mods, especially with a 305.

However, a 305 can be built for some decent power output with the right combonation of parts (not as much as an equivalent 350, granted).

To give you a better idea of what you need to do to make your 305 faster, we would have to know what form of induction you are using (carbureted, TBI, TPI). Each of the various 305s that came with these cars have different things that will make them go faster depending on what kind it is.

That said, there are some pretty universal mods that will help your engine's power regardless of what it is.

Suspension mods will help you relieve parasitic losses of power going from the engine to the wheels, and help your traction to boot.

A new exhaust system will help, unless your exhaust is already pretty beefy. Headers will almost always make more power than the stock manifolds most engines, as well as a high flow catalytic converter.

A better form of air induction will help as well. Again, depending on what kind of engine you have, upgrades will vary. If you have a carbureted or TBI engine, you probably have a single snorkel air cleaner, which flows hardly enough air for a four banger. It's pretty much up to you on how you want to upgrade that peice. There's many a form of air induction, including cold air intakes, ram air (no real "ram" effect, though), dual snorkel air cleaner, open element and others. Though there is generally a debate over which of these are better, all of them will help to an extent, and all of them are better than the stock peice. Take your pick.

Weight reduction is something you can do without any money at all. Remove all the crap from your car that isn't regularly used or needed. This could include the spare tire, jack, subwoofers/boxes/speakers, back seats if you don't use them, floor mats, windshield washer fluid container, and perhaps even dirt which has accumulated in the carpet. All of it will lessen the load your engine has to force on the car to get it moving.

Of course, it should go without saying that a proper tuneup will always help as well.

Cadillac

Simply awesome.

RSFreak

Now hit it with a 100 shot of juice!!! :hail:



Edit: Sorry for bringing this back from the dead, thats what happens when you do a !

TBI92Camaro

WHAT?!?!?! Ive got that Edelbrock intake, almost the same cam 2 1/2 in dual exhaust dumping into FlowTech Glasspacks long tube headers...I mean, minus the head swaps, Thats my motor!!! :hail: I mean, I never thought Id be making THAT much power! holy crap, I need to start beating on some L98s then j/k.

Red Devil

Put the tools down and buy a bunch of books. If you don't know where to start you shouldn't try yet. You more than likely don't even know or have the proper tools to put together the shortblock. Take your time and you'll do ok.

Red Devil

Those are always key.

blacksheep-1

I'm a 305 guy, and IMHO the best way to get HP out of a 305 is simply build it to the HO spec. The exhaust manifolds are larger, it has an aluminum intake. Go find a low RPM dual plane manifold for about $125, find a generic cam that puts out max HP around 4500rpm, cut a little off the heads to get about 9.8 CR. If you can't get the exhaust manifolds find some small tube headers. I use a rebuilt Q-jet and a recurved early HEI. The little 305 isa a good workhorse but it's limited by design. If you want to go berserk on it then you can get more power, BUT, and this is a big BUT.. you can get more power cheaper with a 350.

BigBadLou

iTrader: (3)

Pardon my ignorant question but could we just bore out our 305's to the 350 specs? The block is identical, right? We would just need a stronger crank, different cam, new pistons and injectors.
Or am I seeing this too simply?

Lou

ME Leigh

No SBC's are only similar/identical externally, the cylinder bores are cast differently for different size engine(305,283,400...)

bulletboy29

quote:
--------------------------------------------------------------------------------
Originally posted by Cadillac

I think the most I saw someone with a 305 getting was 325 HP. Check out this link:

305 to 325 HP.
--------------------------------------------------------------------------------


Is there a little going on here?

Nate86

No, the 305 was just bottlenecked that bad from the factory. Just with headers and a 3" exhaust system alone, they picked up ~35 HP over the what the factory had rated the engine power output.

mdricken

You will be talking well over $1000 to replace your 305 with a rebuilt 350 if you DONT have an existing block that you know is good (ie not cracked).

I replaced my 305 w/a 350 last fall and found that I would need $1500 minimum, plus all the high horsepower goodies ($1000 more in your case). That being said I jus threw down $2000 more and bought the GM ZZ4 crate engine that has 355HP. It's a complete 350 engine minus the carb and oil filter adapter.

Bottom line - If you are serious about putting money down, go all the way with a built 350. Otherwise just mod the 305 without rebuilding it - thats what I did until I had enough money for the 350.

ljnowell

Since when does a 350 core cost $1000. Can you explain this?

mdricken

A 350 rebuild costs $1000 minimum if you have a shop do it + at least a few hundred for a GOOD 350 core.

ljnowell

Exactly, so the cost difference between building a 305 and a 350 is 1-3 hundred dollars

five7kid

iTrader: (14)

Make that "rebuilding", and I'll agree with you.

"Building" an in-hand 305 in a fashion that will enable it make more power, by "bolting on" performance parts, will cost you about $1000 less than doing the same things to a 350 you don't have that has to be rebuilt. Only the individual owner can decide if the extra HP from the 350 is worth the extra $1000.

However, the originator stated he had about $1000 to spend. As I said way back when, $1000 is about enough to do an emissions-legal exhaust and the air cleaner. Or, one could add, enough for a non-emissions-legal exhaust, air cleaner, and cam.

Of course, we haven't heard much from the originator lately...

ljnowell

Thats what I mean. Just pulling a number from air, but say 400 hp. You probably wont get that out of a 305 for very long. So factoring in the cost of a rebuild, its not very much of a difference. If you had a nice condition reasonably mileage engine, it may worth it to bolt on some go fast stuff. If it were me, I wouldnt even do the head swap, though. The 305 will limit your selection on heads.

mdricken

Only $1000 right now? It doesn't make any sense to build a 350 right NOW.

I would invest $500 in the bank and $500 on bolt ons that can go on a 350: Exhaust, Headers, Rear Gears, Suspension, Carb, etc. That way you can get your hands plenty dirty while you save for the high HP mill.

blacksheep-1

The internals (except for the pistons) are DIMENSIONALLY the same. The balance is different for the 350, I presume because of piston weight. (I have a 305 and a 350 crank sitting in front of me as I write this) the 305 is balanced "lighter".

flrtin1

I have had over 400hp from the original 305 from 86-91 and over 500hp on that same motor from 92 till present so longevity of the 305 with higher horsepower isn't a factor

This is true unless you are going to use 76cc heads the 2.02's will work on the 305 with them.

ljnowell

What was the combo?

I have a hard time believing that you got 500HP out of a 305 N/A and it was still streetable.
And some huge domed pistons? Not worth it at all.

THEGENERAL

is this on your engine with the blower??

if so what all have you done to the internals of this beast to get it to hold up that long with out any ill effects...

flrtin1

lol, I never said N/A just making a statement about hp on a 305 hence why the 76cc heads work


The block itself and rods are stock plus its a cast crank....I did break a crank but it was my fault {dumbass move}. I have always had a 6k rev limit on it I don't need to go higher than that with this setup anyway. 55k+ miles with the blower.

Edit: I wasn't making that statement in the $1k context but in the power ability of a 305 context

ljnowell

And you actually proved my point. To get high HP out of a 305 you are going to have a High RPM peak. Expect to have to rev to well over 7000 RPMs (unless you go the forced induction route). The stock bottom end 305 isnt going to like this, hence my statement above. If you have to touch the shortblock, ditch the 305. Save the heads for more 350 specific heads too, you're better off that way.

flrtin1

lol, I just was jumpin in to stir the pot a little
I only had 11.5k on my 305 when I built it, plus for the younger members parts were a whole lot cheaper back in 86. If I hurt this motor to the point I need block work or a new piston (I would have to buy a set because the ones I have are long since discontinued) I would not do another 305 it would be a 350 or bigger

THEGENERAL

paulmoore

I think that I will step into my flame suit before I say this just in case. Eveyone knows that you can't replace displacement, and that the power potential of any engine is derived on it's size(cubic inches) and configuration. I too, have a spare 305 sitting in my shed. I have though about having the block machined for a scat 400 crank and making a 335 stroker. If you build for torque, horsepower will follow. The key is to build the engine to make the broadest torque curve possible, with the peak torque falling in at or around 5200-5300 RPM cause we all know that torque and horsepower are equal at 5252 RPM. Assuming you can get 1hp per cubic inch out of a 305, simply by doing the stroker deal, you could pick up an extra 30 HP/TQ. Not bad for a few hundred dollars(if you were going to rebuild the lower end anyway). Now throw that into something light like an S10 and you've got yourself something.

THEGENERAL

ljnowell

Or you could start with a 350 block, pay a little less for the pistons, and the same for the rest, have less clearancing to do, and have about 50 more cubes. When you compute the cost, a 305 just doesnt add up right.

THEGENERAL

paulmoore

General:That flamethrower smiley is the greatest!

ljnowell: I know what you are saying, and I agree with you 100%. I'm not arguing the fact that you'd make more power with the 350, it is inevitable. But, Some people like to be different, like me, for example. Or, some people might not have the room for another engine to sit around while they build it, or afford the down time of their car when they go to do the swap. And don't forget that when you tell someone that they can't or shouldn't do something it makes them want to do it even more. I plan on doing this with my 305(the 335 stroker deal), hiding it underneath a 350 TPI setup, and dumping it into an 82-92 S10 shortbed.

THEGENERAL

I thought it fit the statement...LOL

FireBreathin305

"theres no replacement for displacement"

bnoon

If you watch ebay long enough, you can practically get parts for a 305 for not much more than shipping, or better yet FREE from a local machine shop.

Over the last two years... I got a set of free 416 heads, then spent $70 having them bowl hogged and cut for 1.94 valves. Purchased the stainless back cut 1.94/1.50 valves on Ebay for $70 shipped w/ locks. Another $40 purchased a set of Lunatti roller cam springs rated for .600 lift including retainers. I already have the stuff to pull the old rocker studs out of the heads and tap the holes... 20,000 mile GM powder metal rods for $60, new splayed main caps kit for $45... all on Ebay.

Oh, by the way, I'm doing a retrofit roller set up using the 3.4L V6 roller lifters and spider tray mods for less than 100 bucks... Using parts scrounged from local yards and jbody.org classifieds.

Then, I'm doing a 334 stroker since I just came across parts to do that for $200 including crank and pistons...

There are a few odds and ends not mentioned here, but I'll be under a grand to get a fresh motor in my car with almost all of the work being done by me.

Why not build a 350 or larger? Been there, done that. I want a broader torque range and good MPG and I will have it. Crazy? Yes... but only in your world...

flrtin1

I just checked Speed Pro piston prices for my application (supercharged) and contrary to what has been said the 350 forged pistons would cost around $90 more than the same 305 forged pistons.
Looking at this discussion I think it all depends on what you have to start with and what your end goal is.
I have well over 500hp and drive it 100% on the street (last time at the track was 88) I always have had street tires on it and have to say if I had any more hp/tq it would be useless because I have a hard time getting what I have down. (also you need to realize no matter what you have there is someone faster than you so you need to know when to stop or you end up with a car you can't drive on the street)
Now if you are building a track car or only are interested in how fast you can go than that’s what you have to build for.
After seeing the piston prices I would have to say I would build a 305 again for my application if I had a good one available but since I have a virgin 327 sitting in the garage that was given to me I will probably go the 350 route.

Edit: I just checked the 327 pistons and they are $50 cheaper than the 350 pistons

flrtin1

Just to add more fuel to the fire

With DD2000 on my set up the difference from a 305 to a 350 both at 9lbs boost (which would require I buy another pulley for the 350 @ $100) is a loss of 5hp and a gain of 39tq

five7kid

iTrader: (14)

And you believe everything DD says?

And you're going to do that to a stock LG4 for $1000 or less?

Let's keep the discussion to the originator's question, please.

RB83L69

350 pistons are $90 a set more than 305, or any other V8 pistons for that matter? On what planet?

Now that we've had our laughs, here's the reality. All these pistons are flat-tops, that being the only configuration that the 305 ones are available in.

350 pistons, $29.95 ea. http://store.summitracing.com/partde...TRW%2DL2256F30

327 pistons, $36.69 ea. http://store.summitracing.com/partde...TRW%2DL2165F30

305 pistons, $30.50 ea. http://store.summitracing.com/defaul...rch&Ntt=l2486f no part detail They don't list them in .030" or .060" overbore on their web page, but I'm sure they're available that way.




Basically, here's how to get big HP numbers out of a 305, in 2 easy steps:

1. Remove 305 and throw in the trash
2. Install larger motor

flrtin1

No I don’t believe everything DD says just like I don't believe everything that is posted here....My point was people want to say things like 350 pistons are cheaper than 305 pistons do your own research and decide what your end goal is when you start so that you only buy parts once not twice even if your buget is $1k

bnoon

So funny, I forgot to...........uh... something........

flrtin1

Oh sorry I was wrong its $91.60 cheaper

L2486F 30 (305) $30.50
L2490F 30 (350) $41.69

five7kid

iTrader: (14)

P/N with "F" suffix is standard bore. "F30" suffix, or "Fxx", is the overbore.

But, with a $1000 budget, you'd better not be considering rebuilding the shortblock and increasing power.

RB83L69

So, what's the L2490F? Obviously not a plain-vanilla piston, like the one I quoted with the link to it, like the only 305 ones available.... it's a floating-pin one with narrow rings. I guess I could list Arias ProStock pistons on there, and compare that price to the stock-replacement SpeedPro, and "prove" that way that the 350 costs 6 times as much to rebuild, too.

Yes I know about the Fxx. I must have fat-fingered it somehow. However, I notice that the L2486F60 is $39.95. http://store.summitracing.com/defaul...h&Ntt=l2486f60 So, what does that "prove"?

And, on what real-world planet, not "DD2k world" with your combo whatever that might be, do you live, that a 305 makes 5 HP more than a 350? That's good for another hearty belly laugh. It'll never happen.

Like I said (although not in exactly these words), it's pointless to build a 305 if you're looking for "high horsepower". On the other hand it's perfectly sensible to do bolt-ons, or things like exhaust and gears and converters and such, that aren't part of the motor as such, and are applicable to any motor of any size; even heads, as long as you don't spend wheelbarrows of $$$$ on something that is only applicable to a 305. But the minute you have to touch the short block, it's time to toss it, and enlarge the bore with a "bore kit". Forget the "stroker kit", it's more money for less results. Think HP per $$$.