Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
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do u guys think i can get 400hp out of a 305 w/o nitrous or a supercharger? this is my plan, port and polish heads, larger valves, at least a 10:1 compression ratio, .510/.510 cams, edlebrock airgap intake,demon 750 carb, headers, march pullys. maybe a stroker kit?????? ur opinons will be greatly apperciated
anythings possible. that being said im not going to try to talk you out of building the 305 as some will but i have got to ask you a simmple question.
do you think its worth spending more money on a 305 and struggle to get 400hp...or spend less money on the overall build by starting with a larger displacement block?
if its worth it to you, or you are looking for a challenge and have money go for it. To you it'll be a 400hp 305 to me it will be just another 400 hp smallblock...its not "different"
see i just want to work with what i have right now, i defintly have the money to do all the work and it would be a nice challenge to overcome, plus i can say my 305 beat you LT1 and stuff like that.
plus i can say my 305 beat you LT1 and stuff like that.
Thats a quote someone with more money than sense will be able to use.
Why screw yourself? IF you are going to spend the money, why not get 20% more power? I mean really, if you were looking through a catalog, and you could buy 15-20% more HP for 100 bucks, you would do it, right? Thats the difference between a 305 and 350. IF you get 400hp out of a 305 (which is gonna be hard), you would have had 475 out of a 350 with the same parts and work.
You'll need to FULLY PORT the stock heads {not tbi heads} with larger valves or use some other small chamber performance heads. most will need porting too.
Vortecs,,GM 041,186 040 (late camel back w/accessory holes) GM L-98 corvette aluminum
would be good choices. You'd want to maximize the compression ratio for the fuel you'll be using.
You'd want to use a 1.94" intake valve and a 1.50-1.56"
exhaust valve.
You'll need a fairly big cam (I would use a solid or solid roller) (cause of the high rpm required)
The torque curve will be fairly high up in the rpm band, peak hp will be at 7000rpm+ so you'd want to use a very high stall torque converter (8") and very steep rear gearing. 5000rpm+ 4.56:1+
Originally posted by hot91t/a do u guys think i can get 400hp out of a 305 w/o nitrous or a supercharger? this is my plan, port and polish heads, larger valves, at least a 10:1 compression ratio, .510/.510 cams, edlebrock airgap intake,demon 750 carb, headers, march pullys. maybe a stroker kit?????? ur opinons will be greatly apperciated
Is that 400bhp at the rear wheels on a chassis dyno or 400bhp at the crank on an engine dyno? There's a big difference hot91t/a!
You'll need to FULLY PORT the stock heads with larger valves or use some other small chamber performance heads. most will need porting too.
Vortecs,,GM 041,186 040 GM L-98 aluminum
would be good choices. You'd want to maximize the compression ratio for the fuel you'll be using.
You'll need a fairly big cam (I would use a solid or solid roller)
The torque curve will be fairly high up in the rpm band, peak hp will be at 7000rpm+ so you'd want to use a very high stall torque converter and very steep rear gearing.
5000rpm+ 4.56:1+
And at the end of that, you will get beat by 350's with less money invested and less time spent.
You can build 400hp out of a 305 nobody will debate that, is it smart or worth it noway in hell.
__________________ LT1 headed LG4 305 beast! Comp Solid lifter XS-262-10S, 1.6 Roller Rockers, 10.2:1, Holley 4160 600cfm, modded Weiand 7502 intake to fit LT1 heads____ Custom cylinder head cooling. Weiand 8208 Short Water Pump____TH-350 3 series 3.73 with 2 series posi and spacer____ Hedman Hedders 1 5/8 headers and Y-pipe 3in Exhaust, Dynomax 3" Bullet muffler ____Moroso Ultra 40 Wires ACCEL HEI Super Coil ____Competition Engineering 3120 Bolt-on SFC's____Homemade: Wonderbar, solid tie rod sleeves, Aluminum LCA and Panhard Rod with spherical rod ends, alternator and PS bracket, Strut tower brace, and Decoupling torque arm with telescoping link.
3000lbs
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It won't be streetable, and it will require a ton of tuning. This sounds like it's your first build. Go for a 350 hp 350ci and cut yourself some slack. The "working with what you have" logic doesn't apply here, because a built 305 will cost you a lot more than a built 350 by a long shot power for power.
Last edited by anondude13; 11-02-2004 at 02:53 PM.
The "working with what you have" logic doesn't apply here, because a built 305 will cost you a lot more than a built 350 by a long shot power for power.
Originally posted by hot91t/a some poeple just wonna be different... not everyone wants a 350
Thats what im talking about almost EVERYONE has a 350 and i just wanna be different, also the 400hp will be at the crank [/b][/quote]
well if you wanna be different then build a 400 or a 357 or a 355 or , well the list will go on but to limit yourself to the power that a 305 will put out is rediculous when your looking at putting as much money as you are talking about into it ...
here we go again...LOL
__________________ •"I work on my chevy because I want to ..I work on your ford because you pay me too"------THEGENERAL
•"If it's true that we are here to help others, then what exactly are the others here for?"-------George Carlin
•There's a place for all of gods creatures .....right next to the Potatoes & Gravy!
•R.I.P. Johnny Carson, 1925 - 2005 You will be missed.......
•"Never argue with an idiot, they'll just bring you down to their level and beat you with experience".....METALICAMARORS
Originally posted by ljnowell And at the end of that, you will get beat by 350's with less money invested and less time spent.
Not nessessairily true. It costs about the same to soup up a 305 with new (ported) heads, a cam, intake, carb,
headers etc as a base 350ci. The cam will be bigger to achieve 400bHP on a 305 based motor cause it will have to rev higher, a 305 will need a single plane manifold where a 350 can do it with a dual plane (both cost the same)
The only real difference is the 305 based combo will need a much higher stall converter and higher rear gearing that the 350ci based motor.
The motor will be on the radical side but is not unmanageable for the street.
It will run with any 400hp 350 motor. the power is the same.
Originally posted by five7kid Ever see anyone try to drive a tweaky car on the street? Not only have I seen it, I've done it. It's not a pretty picture.
Same here. My engine would stall as soon as it left gear when I bought it. It required a large amount of tuning to get it streetable, but even now I know that no soccer mom would want to commute in it. I also know that I'm gonna have to keep up with tuning it to keep it running well. Big cams also like to stall when you give them a lot of load at idle (a slow sharp turn while trying to park for example). In other words, I kinda wish I had a bit less cam. You will need more cam, and it will be a smaller motor, which will make it even less streetable. Sounds like you're new to this and read the ultimate TBI page. Trust me, we've all been there, we understand why this is not a great idea.
Last edited by anondude13; 11-02-2004 at 11:04 PM.
A 400 HP 350 that makes that power at 5500 RPMs will likely have more "area under the curve" than a 400 HP @ 7000 RPM 305. The only way a 400 HP 305 will keep up with a 400 HP 350 is if the 305 is at peak power for the entire race. Since most race cars start at an RPM below the peak power (but properly set up, at or above the peak torque), the 350 is probably going to get there first.
I have maintained that I am faster for the money spent having warmed up my 305 than I would have had I gone for a 350. Why? Because everything I had to do to the 305 would also have had to have been done to a 350 (exhaust, cam, intake, air cleaner, etc.). But, the originator isn't talking about doing like I did, but getting into the 305 shortblock, where 350 parts are actually no more and often less expensive than 305 parts. The extra cubes and breathing capability of a 350 is going to walk all over a 305 built with the same amount of money.
Originally posted by five7kid Peak power doesn't tell it all.
A 400 HP 350 that makes that power at 5500 RPMs will likely have more "area under the curve" than a 400 HP @ 7000 RPM 305. The only way a 400 HP 305 will keep up with a 400 HP 350 is if the 305 is at peak power for the entire race. Since most race cars start at an RPM below the peak power (but properly set up, at or above the peak torque), the 350 is probably going to get there first.
Thats why the 400hp 305 will need a very high stall converter matched to its torque band and a very high rear gear ratio. But 400BHP is 400BHP and the two cars will run very simular. the small ci motored car will be easier to hook up and launch (less torque) so it has a good chance.
A motor with less " area under the curve" in the power band only needs more transmission gears to keep it in the best power band. (like a 5speed trans)
But the 305's power band will be no more narrower than
a 350's power band. it will be lower ( lower torque output) and occur at a higher rpm requiring a high rear gear ratio and high revs.
It's just a matter of selecting and quardinating the camshaft, converter and rear gearing to match the engines power band to the car. it will be a screamer thou.
A 400 horse 305 would do fine on the track, even if it would be a rip-off. But there's no question it would not be nearly as streetable as an equally powered 350. I would also wager that the mileage would be terrible with a huge cam and steap rear.
Price the pistons, thats one thing that is more expensive. You will end up spending more money, and more time tuning it, because of its moodiness. In the end, you will be out more money, just to lose to guys with a 350. If you put the exact same parts in a 350 it would be loads more powerful. If we were in a world without 350's I could see it, but we're not, so why waste money on it?
Like five7 said
Quote:
But, go ahead. Be different, be slower, be last. At least you'll have the satisfaction of knowing in your mind that "It's just a 305."
Originally posted by ljnowell Price the pistons, thats one thing that is more expensive. You will end up spending more money, and more time tuning it, because of its moodiness. In the end, you will be out more money, just to lose to guys with a 350. If you put the exact same parts in a 350 it would be loads more powerful. If we were in a world without 350's I could see it, but we're not, so why waste money on it?
Like five7 said
This engine only needs cast hypertectic pistons
they (305 or 350 ci) cost the same or very close to it.
If you have a good basic ( healthy) 305 shortblock that already had flat top pistons you're half way there.
the poster asked if it can be done,, yes it can and its not that hard and not that much different or costly than building a 350 to the same power level (400bhp)
a 350 with the same parts will only make about 20/25 more peak hp than a the same pattes on a 305 . it will make more torque.
The practicality of building a screaming 400bhp budget 305 is another matter. yes it will be a little hard on gas around town but again not really much different than a 400hp 350.
Hot 91: What parts do you have already to work with?
Well, we're straying from the original theme a bit, but think about what's happening:
More converter to get the R's up; more gear to make up for the reduced torque output. Well, the torque at the wheels will be the same with either engine.
But, back to the "area under the curve": In the real world, the larger bore of the 350 is going to alter the breathing characteristics. If the 305 makes 400 HP, it is not going to have a very broad torque curve. The 350 will make the 400 HP with a broader torque curve. And, in the real world, torque converters and gears aren't going to make up for that deficiency. I know of no racing situation in which the engine remains at the peak HP level throughout the race.
Originally posted by five7kid Well, we're straying from the original theme a bit, but think about what's happening:
More converter to get the R's up; more gear to make up for the reduced torque output. Well, the torque at the wheels will be the same with either engine.
But, back to the "area under the curve": In the real world, the larger bore of the 350 is going to alter the breathing characteristics. If the 305 makes 400 HP, it is not going to have a very broad torque curve. The 350 will make the 400 HP with a broader torque curve. And, in the real world, torque converters and gears aren't going to make up for that deficiency. I know of no racing situation in which the engine remains at the peak HP level throughout the race.
It doesn;t need to. It needs to crowd the rpm between peak torque on the low end and about 10% above the peak power rpm at the high end for best acceleration. Only needs the right converter and gearing and shiftpoints.
the only thing i have is my block, since it was a TPI and i want to change it to carburated and see if this is a good idea to achive the 400hp out of the 305
Expecting to spin a 305 to 7000 RPMs will require healthy upgrades to the rotating assembly. Expensive parts. They'd cost the same as what it would take to get a 350 to spin to the same RPMs. At the same RPMs, a 350 would make a lot more power.
Unless you are not spending a dime on the shortblock (which you can't expect if you expect to get 400 HP out of it), it doesn't make any sense to "use what you have". If you "use what you have", you shouldn't expect 400 HP, or at the very least, you shouldn't expect it to make 400 HP for very long.
The dirty little secret that nobody wants to talk about is this wonderful 400 HP magazine 305 failed on the dyno.
Yes, they have no bearing on what SBC engine you have. A SBC is a SBC. Get a L98 350 convert it to carb and go. If you find a healthy L98 shortbock i would just stick with that and bolt on some good power parts.
Originally posted by hot91t/a well if i go with the 350 and do the same stuff to it will i be able to keep my tranny and rear end???
Look, I hope You don't get mad at me for saying this, but if You need to ask such a noob question, then building a 400HP motor is the last thing You should be trying. Maybee just get some experience under Your belt, do a cheapo rebuild on the 305. Once You have that done and know some of the pitfalls to avoid when doing engine work, then You could step up to something more serious, use more expensive parts, shoot for more power etc. By then You will have experience with the Chevy smallblock, maybee not a whole lot, but enough to not want to even think about building a 400hp 305, rather, You will be asking about a
383 or 406 or something similar. Again, I mean no offense, just offering my opinion...
Why don't we be realistic here, max theoretical power levels aside this guy is going to be lucky to get 300hp out a budget, newbie ported stock heads, streetable cam 305... And that won't be easy....
__________________ Ray87Z
-87 Z28 w/ a Vortec headed 350.
R.I.P. - Just totaled by a 16 year old girl in a 94 Mustang, go figure....
-New ride, 94 Z28 - LT1, A4 w/ 3.23s
new mods: Edelbrock headers, gutted cat, magnaflow catback, Moroso CAI
Originally posted by tommyt Look, I hope You don't get mad at me for saying this, but if You need to ask such a noob question, then building a 400HP motor is the last thing You should be trying. Maybee just get some experience under Your belt, do a cheapo rebuild on the 305. Once You have that done and know some of the pitfalls to avoid when doing engine work, then You could step up to something more serious, use more expensive parts, shoot for more power etc. By then You will have experience with the Chevy smallblock, maybee not a whole lot, but enough to not want to even think about building a 400hp 305, rather, You will be asking about a
383 or 406 or something similar. Again, I mean no offense, just offering my opinion...
I agree. In fact I'll take it one step further. If your 305 doesn't need a rebuild at this point, find a local gearhead to learn a few tricks from and try to do some maintenance and restoration first. I've been working on GM's for 2 years now and I've learned a lot, but I wouldn't feel completely comfortable with an engine rebuild myself, however I remember a time that I thought it would be easy.
I have a 8000 dollar 327 for 410 hp before aftermarket heads and the nitrus. the price includes parts and machine work--everything is balanced and sfi approved--bottom line i wish I would have put that money into a big block 468 more power and streetable
Originally posted by r3pp3r If your 305 doesn't need a rebuild at this point,
i spun a bearing on it and thats why i want to rebuild it and stuff, its my first muscle car and i want to do something with it and i have some experiances with engines, i read articals, books, and just personal experiance, i kind of know what im talking about but it doesnt hurt getting comments from people with more knowledge than me
Originally posted by Rick King I have a 8000 dollar 327 for 410 hp before aftermarket heads and the nitrus. the price includes parts and machine work--everything is balanced and sfi approved--bottom line i wish I would have put that money into a big block 468 more power and streetable
ouch sorry to hear of that....this is exactly why you should always start with the biggest displacement you can or want ...LOL..itll usually never let you down...
Quote:
Originally posted by hot91t/a i spun a bearing on it and thats why i want to rebuild it and stuff, its my first muscle car and i want to do something with it and i have some experiances with engines, i read articals, books, and just personal experiance, i kind of know what im talking about but it doesnt hurt getting comments from people with more knowledge than me
well id still go find a nice 350 then especially since you spun a bearing in the 305 ...if your going to have to do machine work to it they your just shooting yourself in the foot by doing it all to a 305
as far as muscle cars go these are not muscle cars..LOL..they are more of a pony car far from muscle...
__________________ •"I work on my chevy because I want to ..I work on your ford because you pay me too"------THEGENERAL
•"If it's true that we are here to help others, then what exactly are the others here for?"-------George Carlin
•There's a place for all of gods creatures .....right next to the Potatoes & Gravy!
•R.I.P. Johnny Carson, 1925 - 2005 You will be missed.......
•"Never argue with an idiot, they'll just bring you down to their level and beat you with experience".....METALICAMARORS
heck if you want to do it, it is up to you with that 305. I would get a roller one two start with. then i would stroke it out to 333 ci and get a good set of iron eagle 305 heads ported. I would only run it to 6500 rpms. Heck a great induction for hp would be a tunnel ram with 2 390 ctm holly carbs. Go to http://www.enginekits.com/Catalog04.pdf for a stroker kit and have it internaly ballanced
as fro a cam will that depends on what you want solid roller for more power
headers
super comp
just my 2 cents this motor would be about $4000 to $5000 dollars
on the other hand if you get a stock 350 and have it balanced and install arp rod bolts, and then some decient heads and a blower you can run 500 hp of reliable motor all day on 93 gas for the same money.
THEGENERAL quote:
--------------------------------------------------------------------------------
Originally posted by Rick King
I have a 8000 dollar 327 for 410 hp before aftermarket heads and the nitrus. the price includes parts and machine work--everything is balanced and sfi approved--bottom line i wish I would have put that money into a big block 468 more power and streetable
--------------------------------------------------------------------------------
ouch sorry to hear of that....this is exactly why you should always start with the biggest displacement you can or want ...LOL..itll usually never let you down...
yea I was quit young to the automotive world and thought I had the world by the balls-- it is cool to come of the dyno and have 410 rwhp with Cammel bach heads and a gm block with only 327 cubes. at least that 8000 was carb to oil pan and the flywheel and clutch + the electronics-- now for some canfield or brodox with nos
later and GB
anyone want to buy a 327 it halls *** 11.25 in the quarter with a 3600 lbs car no nos
This thread is a waste of time. Let the kid **** himself. Its his car and his money, he should learn this leason the hard way so when the next 16 yr old comes on wanting power from a 305 he can tell him what a waste of time that is and start another long worthless thread.
heck if you want to do it, it is up to you with that 305. I would get a roller one two start with. then i would stroke it out to 333 ci and get a good set of iron eagle 305 heads ported. I would only run it to 6500 rpms. Heck a great induction for hp would be a tunnel ram with 2 390 ctm holly carbs. Go to http://www.enginekits.com/Catalog04.pdf for a stroker kit and have it internaly ballanced
With the advancements in modern carb technology, why waste money on a tunnel ram and dual carbs? You can make just as much power on a 305 with a single carb and a normal intake.
As far as wasting money rebuilding a 305, thats exactly what it is. If a 305 needs any machine work, or if you need to touch the shortblock at all, get a 350. No matter what you do to it, it will yield less HP than a 350 with similar mods. Dont listen to anyone that tells you different, unless you have money to burn.
world s/r torquer 305 heads, ported to hell and back LOL
cam, solid roller would be sweet but i think with hydro roller and rev kit, you will be alright
something with 224/230 with lots of lift.
RPM intake might be little small. Maybe victor jr.
750 demon/or whatever carb
lots of time tuning that bad boy
should get you 400 hp on crank.
the key is matching components to make power. Go for it if you will. Reving to 6500rpm or so is sweet, but your gonna need a stout bottom end!
hot91t/a,
I also asked the same question when I bought my camaro. Is it possible to build a 400hp 305? I also got many of the same responses you are getting. While you may think it's cool to build a high-hp 305, it will not be a very efficient use of your money. After taking the advice of the guys on this board, I went and bought a 406 small block and dropped it in place. I personally think it sounds a lot cooler to say "I have a 406 small block under the hood"
what i would do is rip apart the bottom end and get the crank as light and you can then put over size bearings in for the mains to get it a little bit tighter bottom end then put a set of 10.5:1 pistons in with the 64cc or 58cc fueil heads then deck the block and the heads so you can up the compression to 14:1 port the hell out of the heads 2.02 intake and 1.60 exhust get a high raise intake with a 2" carb spacer holley 750 DP get a cam with over .500 lift then put 1.6 rockers on the exhust vavles and 1.5 on the intake get a belt driven timeing chain setup elec. water pump then on the alt. put a toggle switch on the reg. so when you running the 1/4 the alt isn't eating HP if its a roller block get a REV kit if not then get comp cam racing lifters not stock harder one pices push rods full roller rockers not roller tip get matched springs for the cam you plan on useing get headers with 1 3/4" primarys or bigger have it be open headers your going to need an MSD 6AL box if you going to use a trans brake get a two step for the MSD get the blaster 3 coil run about 36º of timeing 110 octane race gas oil pressure NOT HIGH VOLUME oil pump get rocker stud gridles and main stud gridle get a wage tray so you can keep the oil off the crank get a deep sump oil pan up grade the fuel system then see what you can do with that 305 (i'd bore it out .030 over so you know the rings are going to get a nice seal )
do al that to a 305 then do it to a 350 and see what one will have more power.... BUT nice thing about this is that if you did do all this to the 305 and later you want to get a 350 everythign you put in that 305 you can put in that 350 other then the pistons and the crank if its a 2 pice or one pice rear main
there are alot of other things you can do to free up some HP there are mods you can do to the carb and all that. just look around see what you can find. only reason i'm not still running my 305 is becuase i blew it up because i didn't have a rev limter and over reved the motor :-( 305's don't like going 9,000 rpm that long LoL
This thread is a waste of time. Let the kid **** himself. Its his car and his money, he should learn this leason the hard way so when the next 16 yr old comes on wanting power from a 305 he can tell him what a waste of time that is and start another long worthless thread. 
