ITSANSS

Howdy, fellas. I have pretty much decided on building a 305c.i. blow-thru carburetor turbocharger setup.

I have a pretty basic knowledge of high performance engines; what parts make proven power and last at the same time.

I have an idea of what parts would work well, but would like ya'll's input.

Theoretically, spinning a ton of RPM + turbocharger = a fast car.

I would like horsepower levels from 400-600. I do not want any less than 400, but do not want to get it past 600 much with a factory cast-iron block.

I reckon that if people can get 400 horses out of their 305s naturally aspirated, then I can get that and more with using a turbine.

Now, knowing which parts are good and which are not is half the battle. I need to know what parts are not only good, but what will work well together and be reliable.

Forged everything, of course.
Dished pistons (to lower compression for the boost) (Brand?)
5.7" rods (Brand?)
Best rod bolts I can find (ARP?)
Was thinking about "de-stroking" the engine with a 327's crankshaft at 3.25" stroke instead of the factory 3.48". Bad idea? (Brand?)
Cylinder heads? (Aluminum, of course. CC? Brand? Valve sizes? Possibly 1.94" intake valve and a 1.55" exhaust valve?)
I know for turbocharged applications, camshafts usually resemble factory specifications...Any suggestions? (Brand?)
Intake (Aluminum, of course. Dual plane? Brand?)
I will check out CSU for carburetors.

Thanks a lot, gang!


P.S. PLEASE do not tell me to get a 350. lol

whytryz28

iTrader: (28)

Destroking the engine will allow it to spin faster and reach higher RPMs. If the block is a 2-bolt main get it drilled out to a 4-bolt main with 18 degree splayed ends. You dont really need aluminum heads, You can make great power with Dart Iron Eagle heads. 4340 I beam rods will hold up from SCAT. And a 5140 Steel crank, or even a factory steel crank. As of camshafts forced induction engines like cams with a 112-114 lobe seperation, and the exhaust duration 10-12 degrees greater then the intake.

Hope some of this helps with what parts your looking for.

ITSANSS

whytryz28, that definitely gives me peace of mind. Several of the things you mentioned are things that I already had in mind, which kind of tells me I am on the right track.

I forgot to mention the main caps. As far as I know (from what I have read), there is no such thing as a factory 4-bolt 305. But, like you said, machine that sucker and make it a 4-bolt.

As far as aluminum heads go, I know I do not exactly need aluminum, but I figure shaving 25 lbs./head couldn't hurt, and the elite heat-rejection aluminum offers is just about un-beatable. Plus, with forced-induction there is always the greater risk of detonation and aluminum heads will help out with that considerably.

I will do a little more research on camshafts, I reckon.

Also, I have been reading up on Scat's products. I am thinking of maybe the whole bottom-end being Scat stuff.

A littlre more in depth....What kind of combustion chamber would I need to look for to get anywhere from 8.00-8.5:1 compression ratio? Also, valve sizes?

Thanks again!

whytryz28

iTrader: (28)

How much Boost do you plan on running?

whiteghost

iTrader: (2)

What is it that has made you fall in love with the 305? I am assuming (3.763" x 3.48") The smaller bore is going to limit the size of the valves you can run and it wont rev any higher than a 350.

I know turbo motors can get by with smaller valves just fine, but your lag will be increased and so will your power under the curve.

Just curious why you're preferring the 305 when 350's are more plentiful and cheaper to build, and make more power. Care to explain?

ITSANSS

Good question. I am not quite sure just yet. I reckon I will keep adding until I reach my desired amount of horsepower. From what I have read, it should not take much to get that kind of horsepower.

From the many MANY hours I have spent reading on http://www.theturboforums.com/, I have only seen a small handful of turbocharged 305 applications. Most of the people that have used turbochargers on their 305s have mostly not changed a thing on the engine. Several have done some cylinder head work and such, but as far as the bottom-end goes, they have basically left it stock. This is why I feel confident on being able to make 500 horses safely with a “highly” modified 305. :-D

I believe most of the turbo. 305 crowd are running 10p.s.i. or less. (On stock engines...)

ITSANSS

whiteghost, I know parts availalbilty for the 350s are more plentiful, can make more power, and are cheaper.

I could always swap in a 350, but how original would that be?

I know I am not the first to try and hot-rod a 5.0L and I will not be the last, but compared to the bigger small blocks, turbocharged 305s are nearly non-existant. How cool would it be to make a 7.00 second pass in the 1/8th mile and get back to the pits and be able to tell anyone who asks that I am running a 305? :-)

This will be going in my 1988 Chevrolet Monte Carlo SS, by the way. I want to pull up to a Turbo. Regal and ask, "Want to see what Buick could have done with two more cylinders?". :-D Gotta' figure if Buick could make the G-body move pretty quickly with a six cylinder, why can't I make mine move even quicker with eight?

whytryz28

iTrader: (28)

You can make 500hp easily. 9.0:1 compression on 10lbs will get you there in a heart beat.

A 383 chevelle on 9.5:1 compression running 10 lbs intercooled made 572 rwhp (673 crank hp) on pump gas with Dart iron eagle heads. Steel crank and rods, but forged pistons a must.

whiteghost

iTrader: (2)

Now I've got your drift. Uniqueness is very cool, when its accompanied by kick *** power, and like you said, if she blows up you are a quick motor swap away from having a turbo 350. Good luck with the build and please post up any additional questions you might have.

64cc heads should put you at around 9.1:1 CR which is a good balance of off boost responsiveness and max boost tolerance.

As for a cam, you dont have to go too crazy, like you said. something right around .480 lift with 220/230 duration at .050 should do fine.

For the blow through carb setup, I'd go with a single plane low rise intake(edelbrock torquer or similar) this will give you better fuel distribution to prevent leaning out the corner cylinders while giving up only a little low end torque , plus they're dirt cheap.

ITSANSS

Thanks for the replies, gang.

I figure it would be quite the easy task in making the power I would like to. :-)

My way of thinking is if I want to run five hundred ponies, I am going to build the engine to withstand twice as much. I figure the weakest point in what I would like to build will be the block, but I can't see spending $2K on an aftermarket (bare!) block. Plus, I do not think I would even find anything in the way of a 305 aftermarket block. I am not even going to look. lol

9.1:1 compression? I kinda' sorta' would like it to be a tad bit less. Detonation scares me. Haha I am convinced using an intercooler is the way to go, which will help considerably with heat and detonation issues. Also, aluminum heads that I would like to run will help out.

I have an aluminum single-plane Edlebrock Torker intake manifold currently on my L69, but I think it is possibly warped. My thermostat housing forever leaks (it is chrome). I have scoured the Internet looking for ways that people have gotten theirs to not leak, and all of them have worked for me....for about two weeks, and then it starts leaking again. lol Hopefully when I am riding on the back bumper the cylinders won't lean out. ;-D Dang carburetors!

Keep the posts coming! Thanks again!

CAMAROZ28SS

iTrader: (5)

take the 305 and use it as a boat anchor. get a 350 4 bolt and be done

whiteghost

iTrader: (2)

wow- did you read this thread or just jump to conclusions after reading the title?

ITSANSS- if you throw some heads w/ a bigger chamber 72 or 74cc you can drop the cr down to the mid 8's and give yourself more room to add boost when you get sick of your initial setup.

Can you get e85 where you are? If so that would give you an even bigger detonation safety cushion, you'll just need a bit more fuel pump and jet. Have you made any more decisions?

mrdragster1970

.

Don't worry about the know it all, wanna be's. Good luck and I hope it comes out better than you expected. My two cents, don't destroke it, you can use less boost, and lower the power band. Another vote for E-85 or even E-100 if it's a track car. You can always say it's a 305 if you want, they can't tell from the outside. One more thought, why must it be an original 305 block?? Bigger bore is usually better, 99% of the time. Have fun and do it your way, no matter what the morons say!!

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ITSANSS

Hey, ya'll. Haven't had a chance to get online in a little while. Something about a full-time job, part-time job, and full-time school that takes up the majority of my days.

That I am aware of, there aren't any E85 fuel stations here where I am. There is a place mid-town that supplies 114 octane racing fuel, but I really do not see myself needing THAT high of an octane for the small amount of power I will be (hopefully) making.

I had the thought of putting a 350c.i. in there and just saying it was a 305; since it would be cheaper and all and not tellable from the outside, but I am pretty sure I am set on the good ole L69. :-)

Don't de-stroke it, huh? I know bigger bore is typically better, but then it wouldn't really be a 305. Haha Actually, de-stroking it with a 327 crankshaft and a 0.030" overbore would make it a 289 (3.25" stroke and a 3.766" bore) So I reckon it still wouldn't be a 305 then!...More air flowing through that sucker, the more power! A 0.030" overbore on a 350 block (4.030") and a 3.25" stroke would make it a 331, rounded up would be a 335, which is a "bored and stroked 305". Hmmmmmm I hadn't really put any thought into getting a 4.00" bore block and slicing a few cubic inches off of it to make it a "bored and stroked H.O. 305". :-)

Cheaper...More power potential....No one will know....Hmm Another option, I reckon. :-D