307vs 305

[truckdude239]

okay i recenty sored a 305 engine i am going to start cleaning up and install in my truck till i start engine class next semeter and rebuild the 307 but my question is would the toqure on the bolts (internal, head bolts ect..) be the same on the 305 as the 307? reason i'm asking i got a book with all the spec.s for the 307

[Green Machine]

Yep - They are the same.

[CMars45000]

Originally Posted by Green Machine

Yep - They are the same.

The same? I am pretty sure they are not...Close to the same displacement, yes but NOT the same...

The 307 is basically a 283 block with a 327 crank (3.875" Bore X 3.25" Stroke)

The 305 has a 3.74" Bore and 3.48" Stroke (the same as a 350)

[crazy longhorn]

They are different displacements (bore/stroke), but i think the ? was on bolt tork up......yup they are the same!..... L

[CMars45000]

Dirka... Guess it would help if I put the Bud Light can down and read the orig. post huh...

lmao...

[JRB]

If you bore the cylinder walls 1/8th of an inch on the 307 you will basically have a stock 327 small journal of coarse but still a respectable motor. I did one in my 57 chevy Bigwindow short step. Great running motor.

JRB

[bretcopsey]

I'm pretty sure all "gen 1" small blocks share the same torque specs...


JRB, can the 307 safely handle a .125 overbore??

[wolfthing2000]

So , which is the better short block 307 with the 327 crank or the 305 with the 350 crank. More torque on the 305 I am suspecting?? And can you safely bore the 307 .125 over???? 327s are cool motors!

[crazy longhorn]

Originally Posted by wolfthing2000

So , which is the better short block 307 with the 327 crank or the 305 with the 350 crank. More torque on the 305 I am suspecting?? And can you safely bore the 307 .125 over???? 327s are cool motors!

IMO, the 307 is a better engine than the 305.....what it lacks in stroke, it makes up for in bore size(less shrouding on the valves). The bigger bore engine will respond more favorably to perfomance add ons. the 327 is no doubt much better than both, but I would sonic test the walls before I had someone bor the 307 1/8 " over L

[JRB]

Originally Posted by bretcopsey

I'm pretty sure all "gen 1" small blocks share the same torque specs...


JRB, can the 307 safely handle a .125 overbore??

I had a machine shop in San Diego do mine and he told me it was basically the same block as the 327, I had mine bored to a 4 inch bore vice 3 and 7/8. I also had the motor balanced at the same time. It cost me around $1200 to have it done but you talk about a sweet smooth running small block. It was well worth the money. The 307 has the same stroke as the 327, 3 and 1/4 inches. If you are going to have it done I would make sure the Crank is in good shape and if it isnt have it machined also. If you have some tight chambered Heads like 64cc with 2.02/1.60 heads that would realy bring a motor like that alive. Just some thoughts. Good Luck

JRB

[Longhorn Man]

this is just my opinion here...byt that's a lot to spend to end up with such a small motor. You need torque, which is a natural byproduct of increased CID. And personally, if I wanted to make a 327, wouldn't it make more sence to grab a 350, check the boor on it and then slap in the 307 crank? Machining would be a bit cheaper... and at $1200 for machining... you could EASILY score a good 350 core to do this, no matter how hard they are to locate in your area.

[JRB]

Originally Posted by Longhorn Man

this is just my opinion here...byt that's a lot to spend to end up with such a small motor. You need torque, which is a natural byproduct of increased CID. And personally, if I wanted to make a 327, wouldn't it make more sence to grab a 350, check the boor on it and then slap in the 307 crank? Machining would be a bit cheaper... and at $1200 for machining... you could EASILY score a good 350 core to do this, no matter how hard they are to locate in your area.

Depends on what you mean by good core. When I was done with my 307 to 327 build I knew what I had. I also think it depends on what you want. The guy has a 307 already which means he doesn't need to go look for a core and when he has it done It will be completely new verses maybe ok. I know that I lean to the side of spend the money now but I have been around the block enough times to know that either you spend the money now or get bit in the butt later. A friend of mine just picked up a brand new 350 four bolt main for $1100, so there are all kinds of directions you can go it just depends on what you want and are willing to trust. The only thing I didn't like about the New 350 of my friends was it was stamped made in Mexico. Nothing against mexico just dont like to see it in my Made in America pickup.
JRB

[aaronfab]

Sorry for the corrections, BUT the 307 is a large journal engine, yes the 305 and 350 share the same stroke(3.484), to make a 327 you put the 307 crank into a 302/327/350 block, I personaly would'nt bore an engine out to a stoke bore. The machine work would cost more than a core/rebuilder. A 327 is a great high RPM street engine, where the 350 has a little more torque. Either engine can be built to suit your driving. Back to the first question, yes torque values vary a little from engine to engine and year to year, but not enough that you can't use your 307 specs. Hope this helps.


Aaron

[crazy longhorn]

Originally Posted by aaronfab

Sorry for the corrections, BUT the 307 is a large journal engine, yes the 305 and 350 share the same stroke(3.484), to make a 327 you put the 307 crank into a 302/327/350 block, I personaly would'nt bore an engine out to a stoke bore. The machine work would cost more than a core/rebuilder. A 327 is a great high RPM street engine, where the 350 has a little more torque. Either engine can be built to suit your driving. Back to the first question, yes torque values vary a little from engine to engine and year to year, but not enough that you can't use your 307 specs. Hope this helps. Chev's little 327 did grab a big pc of my hart! The little engine that "could"! I took a lot of trash a few years back on the build.....but she ran like F***in stink! A flatop + 40 327 + LT 1 heads & mild cam......well, she had some gears behind her, but a bad ride anyway! The idle was not, but almost smooth(just a hint of the cam @ idle).....man did that bastard run! I still have that rotating assy, & have very dirty thoughts about the fun......331 inches, Edelbrock rpm heads, nice lumpy cam, & a but load of f in gears. ill put that up against anybody,s bad OLDS/CAD/BUICK on the open road......sit down, hang on & shut the big **** up......have fun. L lord i was born a ramber man, trying to make a livin any way i CAN


Aaron

****IT!

[truckdude239]

the 305 is only going in long enough for me to finsh building my other motors 3 months at tops then the 307 is going back into the truck