Hi

I've a 71 with a 307 on it. I want to modify it to get a 350. Some people said me i've to change my intake, valves and so.

But what exactly i would have to do to get a 350 from this 307 block ?

Thanks!

There isn't anything in a 307 that is useful in building a 350. Just find a 350 and put it into the car.
The 307, like the 305 was an economy engine. The heads have small valves that will choke a 350. The intake is a 2 barrel intake that will choke it too.
The simplest thing is to just get a complete 350 and put it in where the 307 was.

Ahhhhhaaaa, the rods! Those are the same between the 307 and 350 http://www.nastyz28.com/ubb/wink.gif . The 307 has the same stroke as the 327, but the crank is balanced different. The 307 shared the same bore with the 283 and no 307 block wilkl tolerate boring to 4.00" to make it a 327 or a 350. Heads will 'bolt up' but pretty useless. Most of the 307's had large chambers, low compression and were intended as a 2bbl, low performance 'econo' V-8. They work GREAT in light weight jeeps where you want to idle around rough country, but otherwise they were intended as basic transportation, not much more.
Like Gary said,, ya got pretty much nothing there that is a start of a 350.

The block would make a decent base for a shop coffe table, clean it up good, clear it to prevent rust, and attach a clear top.

On this table you can put the paperwork to order a 350.

The 307 crank can be made into a neato barstool too... To sit on when you build the 350.

Um....

Pistons make great ashtrays, if you smoke...

thats all I got.

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'03 Yellow S-10 4.3L - "The Bus"
'75 LT in progress again...

a 307 with flat tops
1.94 Fuelie heads with 64cc chambers
or an equivilent aftermarket head
a decent cam in the .440-.480" lift range
218-230 duration
a dual plane 4 barrel
600 cfm or Q-jet
1.5 to 1.63" dia headers
will whoop MANY 350's who have mis-matched components

The same parts above on a 350 would be better though.

a 307 isnt all that bad.. it is literally a stroked 283.. and everyone knows the 283 was a bad ass engine back in the day...

a good set of heads to raise compression a good cam and intake/carb and headers.. i think 300HP isnt really that diffacult for a 307

307 = boat anchor

Do yourself a favor, and find a 350

btw you can't turn a 307 into a 350.

Do a little looking around and you can probably find a good used 350 for about $500-$600. There is a yard near me that specializes in this type of thing and I know two people that have bought complete 350's there for $600 with good results. That isn't a bad deal for pretty much guaranteed boost of 40 to 50 lb/ft of torque.

Actually, good used Chevy 350's are getting a little bit scarce around here. (Columbus Ohio). All of the local bone yards are selling them to some national rebuilder of some sort.

$500-600 sounds about right. I had a chance to buy a pretty fresh 350 for about $600.oo not that long ago.

Chris

i think hes from Argentina (at least his profile says so) it mgiht be kinda hard to find a 350 there.. but i have no idea...

Don't sell those 307's short....put one in
my wifes 72 Monte Carlo (heavy car) but it ain't stock.

Flat top pistons
Comp Cams Dual Energy 265 cam
Edelbrock Performer EPS intake
Edelbrock 600 cfm carb
Flowmaster After burner headers
DUal exhaust with series 40 Flowmasters
B&M Tork master 2000 Converter
B&M Shift kit

Haven't track tested it but it will flat out haul butt.

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If all else fails...Tap lightly with a 5lb hammer!

I ran a 307 .040 over(313) with flat tops 10:1 compression, a Chevy 350 hp 327 cam, a set of 305 heads that were upsized to 1.94 intake and 1.5 exhaust, pocket ported and gasket matched to a Felpro medium race port gasket. I topped it off with a Performer RPM Air gap intake and a holley 600. I used roller rockers and the motor dyno'ed on the stand at 360 hp at 6000 rpm. Not great torque at 360 ft/lbs at 4500, but I put it in a Datsun 280Z and had a blast with it.

The 307 revs quick and high, it can be a decent engine in a light car or street rod, but for the same $ you will get a bigger bang for your buck with a 350.

Jon