I have an 85 fullsize 4x4 Jimmy. It has the famous 305 V-8. I have heard that you can put vortec 350 heads on it, and bump it up 40 hp just by doing that. And if you add the intake for the heads and a highpo cam, could possibly see 300+ hp. So my question is if its possible, do they just bolt up or do you have to do some milling? Just want something hardly nobody else has.:smokin:

You can do a search on the net for a build that hotrod did on a mini mouse motor a few years ago. Most are going to tell you to pull it and use it for a boat anchor, I say if you do any upgrades do them with the "I will eventually be installing this stuff on a 350" and do not get wild with the cam and run it until it blows.

My buddy did this to his iroc last year. I think he called summit and they fixed him up with the intake? I would call them and see what they got. Why not just got with the 350?

a 305 can make about 300 hp with the right parts and still be driveable.

takes some research. if you do it right and plan it right, the parts will swap to a 350 that will make about 375 hp. this way, you only invest once.

A friend of mine emulated this build and it ran pretty strong.
http://www.hioutput.com/tech/343hp/343hp.html

a 305 is going to react the same as a 350 when you add performance parts to it they are going to increase the output of the motor you just wont see quite as much power from the 305 as you would from larger a displacement motor so if you have the 305 just use it and save yourself the cost of having to find and buy a 350. i have a 305 in my truck and it turns my 44's over all day

the problem a 305 has is bore size.
that means you cant get wild with camshaft and intake valve size... unless you get wild with the cam and stay with stock intake valves... to make a motor breathe, you need a few things.

1. larger valves. 305 valves stock are 1.84/1.50 hard to get much bigger without a bigger bore
2. larger bore a 350 has a 4 inch bore, which will let you run as large as a 2.055 valve with the 4" bore, and maybe larger, if you do some work.
3. a well thought out valve job
4. pocket porting under the valves to let the air flow past the valve without obstruction
5. enough intake tract area to let the air come into the motor unrestricted, or at least not "in choke".
6. a big enough carb to allow airflow to the cylinder
7. a decent intake that has free flowing bends in the runners, not choking or restrictive.

Restriction and bends of a dual plane intake make up torque, but a single plane will make the most top end power. a 305 doesnt have either in its equation. it needs a dual plane.

Thanks guys, been away from the computer. Planning on getting some 36's soon and just looking for some more umph! Gears would help alot, 3.08's bring the SUCK! I figure around 300 ponies is enough for dd and mild wheeling. While i already have the 305 and "could" achive my goal, I just thought a stout 305 would be nice.

I found this while searching, it doesn't say anything about porting or milling, so I guess it answers my question.

http://www.goingfaster.com/spo/325_horsepower_305_cid_chevrolet.html

What do you guys think?

What kinda budget you look at? There is some good deal on craigslist.

I like the idea of the link. You could aslo stroker it along with those parts and make even more poneys. By the time you did all the stuff in the link you would be lookin at around 800? I would go talk to the machine shop locally and see what they have to say. They might have parts good and cheap.

www.enginekits.com

shop out of bakersfield ca. they make a reasonably priced 335 stroker kit for the 305 using a reground 400 crank. cam heads and that kit oughta make some decent power.

throw the 305 away....BBC

Shouldn't be much of a problem doing that swap. The Vortec intake has a different bolt patern - so you'll need the right intake manifold - or you'll have to have yours redrilled. Also - they use center bolt valve covers - so make sure you find a set. Beyond that, the only problem we've ever had with Vortecs is they have a different combustion chamber than old-school SBC heads and we ran into some domed pistons clearance issues.

I had a tired old 305 in my blazer 4.10' and 39.5's on it and it would still whip the tires, not a bad motor just underpowered. I was going to do the vortec head swap and stroker, till I bought my 454. Still it would be a cool build, and maybe give you good milage too.

Shouldn't be much of a problem doing that swap. The Vortec intake has a different bolt patern - so you'll need the right intake manifold - or you'll have to have yours redrilled. Also - they use center bolt valve covers - so make sure you find a set. Beyond that, the only problem we've ever had with Vortecs is they have a different combustion chamber than old-school SBC heads and we ran into some domed pistons clearance issues.

Drilling a non-vortec manifold will not work and therefore is not an option if you decide to go the route of the vortec heads. You can take an old carb manifold and slot two holes to work on a non vortec centerbolt set of heads though.

Drilling a non-vortec manifold will not work and therefore is not an option if you decide to go the route of the vortec heads. You can take an old carb manifold and slot two holes to work on a non vortec centerbolt set of heads though.

Aren't runner angles I wanna call them different?

Drilling a non-vortec manifold will not work and therefore is not an option if you decide to go the route of the vortec heads. You can take an old carb manifold and slot two holes to work on a non vortec centerbolt set of heads though.

"old carb manifold" is what I was talking about.... since there is a old school victor jr. sitting on top of vortec heads out on my buddies garage.. yes.. it works just fine.

Edit: Now that I think about it - we might have drilled/tapped the heads for the bolt patern change. Been too long to remember. Regardless, it's not rocket science.

"old carb manifold" is what I was talking about.... since there is a old school victor jr. sitting on top of vortec heads out on my buddies garage.. yes.. it works just fine.

Edit: Now that I think about it - we might have drilled/tapped the heads for the bolt patern change. Been too long to remember. Regardless, it's not rocket science.

the top of the intake ports using Vortec heads with an old style intake would be very close to air, even if you did manage to get them to seal.

look for a set of 305 vortec heads.........there were a few of those around at one point being sold as L31 heads

the top of the intake ports using Vortec heads with an old style intake would be very close to air, even if you did manage to get them to seal.

They are sealing with 16# of boost out of an S400 so far. What else you got to bitch about? Oh, let me guess - turbos don't work with carbs. Gimme a break.


http://www.abusivemotorsports.com/tech/MarkChevelle/Turbo/Raw/img27.jpg

so.... what are the casting numbers on that set of heads?

so.... what are the casting numbers on that set of heads?

Guessing it's the longer of the two - A218 or 12558062. Only real discernable numbers under the valve cover.

http://www.abusivemotorsports.com/tech/MarkChevelle/Turbo/Raw/IMG_2268.jpg

Bump for a little more input.

I've got a tpi 305 from an '86 F-body. I was looking around on thirdgen and there is a feller there who has built some stout five-liters.

http://www.thirdgen.org/techboard/tbi/435894-300-hp-bolt-l03.html
http://www.thirdgen.org/techboard/tpi/477481-356-rwhp-tpi-310-a.html
http://www.thirdgen.org/techboard/tbi/414991-312-tbi-track-times.html

I don't think I'll go that far with a 305, but I have been thinking of a 302 build.

you will probably like the 305 better... lot more power down low, where a 302 has a shorter stroke *(3.0 vs 3.48) and likes to rev a lot more.

you will probably like the 305 better... lot more power down low, where a 302 has a shorter stroke *(3.0 vs 3.48) and likes to rev a lot more.

That's something else, I've heard of people stroking a 305 and getting a 33x motor, but for that kind of money I could build a 350/383/400 and make more power. But, wouldn't the smaller valves and runners on the 305 heads want to make more torque?

I live in Indiana, dirt, mud, rocks, a bit of everything is here.

At the moment, the only thing I know of that is a plus for the 305 is that I already have it.