I am new to most engines and what not. I want to know what seperates a 305 from a 350? What is the difference between the two? I know that they are both small blocks, but if you had a bare 305 block and a bare 350 block are they the same? Are the 5.0 L parts and the 5.7 L parts interchangable? What are some other important engine specs from both of these sized engines? Thanks for everyone's insight and help!!

- Hogan

 

What is the difference between a 305 and a 350? 45 cubic inches, about 15 horsepower, and 40lbs/ft. I believe some parts if not most of them will be interchangeable, but you were here this a million times over....whatever you can do with a 305, you can do to a 350 and get better results. I guess it really also depends on what kind of 305 it is, if it is Throttle Body Injected, or Tune Port Injected. If they are both TPI, then they have few differences, but if the ones a TBI and the other TPI, you might as well be comparing them between a LS1 and a Cross fire injected V8 I hope this helps.

 

the ONLY thing that will not interchange from a 305 to a 350 is the pistons. i believe that the crank is balanced a little bit differently, but you can have the crank balanced. this, however, is not the case in all of the sbc's.

 

Ok, so what does 305 mean? 305 cubic inches, right, but how is that measured? Where does the 305 # come from and where does the 350 # come from? What makes the 350 bigger than the 305? Thanks!!

 

Alright so if the pistons from a 350 don't fit in a 305 then the only difference would be bore size, correct? So could you take a 305 block and make it a 350? Why does everyone say they have a 305 and they would junk it anyday for a 350 if its easily possible to make a 350 out of a 305 with some bore work??

 

The bore of the 305 is 3.736", and the 350 is 4.000". The cylinder walls are the same thickness. That means the 305 and 350 are different castings. If you try to bore a 305 block out to 4", you'll make the cylinder walls so thin (assuming you don't break through) that they won't hold the pressure/forces of operation.

So, if you have a 305, the only way to get a 350 is to get a block that was cast for 4" bore.

And, it has been discussed many, many times before.

 

thanks man. your knowledge is greatly appreciated!

 

yeah.. it would be just a waste of money. If possible.

 

I was actually looking in the John Lingenfelter on Modifying Small-Block Chevy Engines last week. He has a nice picture describing how a 305 crankshaft and 350 crankshaft are different.

Basically it's how the counterweights line up. Supposely on a 305 you can take a straight edge ruler and lay it down even on the side of all the weights. On a 350 crankshaft this is not possible.

So, if you wanted to use a 350 assembly on a 305 crankshaft lots of mallory metal would have to be add'd if it was even possible. Mallory metal contains a higher density than steel so it's used to add extra weight for balancing. Usually the crank is drilled out and a plug is then weld in place. Basically it'll turn into a big machine shop bill that you could have just saved money in the first place and bought a nice 350 crankshaft.

 

thats says a lot. theres no reason to bother with a 305 in any case!!!

 

i wouldn't say its wasting time to throw a little money at your 305 in the mean time. almost every bolt on you can think of can be used on the 350 as well. you can buy the headers, intake, fuel etc. and just transfer it over when the time comes

 

yes sir.... but i mean temping to make a 305 into a 350 if it is even possible would be a waste..

 

Yeah. I wouldn't want to dump my money into a 305 when the 350 option is readily available. But it's nice to know that it is possible to transfer bolt on parts between the small blocks.

 

(Mod note: This thread was hijacked and has been cleaned. For those wanting to know information outside of the topic of this thread, I'd highly suggest a . And, concentrate on the TBI forum, since that's where the answers to your off-topic questions will be found.)