What is the differences between the 305 and the 350? I heard it was just the cam and the heads and thats it. Someone told me that my 305 can be a 350 just by buyin 350 heads. is this true? He said GM did this to save money. Info. well appreciated!

 

heh..
305 and 350 have just about the same parts that would work both together (cam, intake, heads, just about alot of things, but not everything, like starters, chips, etc.) but even for me (a 16 year old, with a 305) know that just putting 350 heads on isnt gonna consider the car a 350, the engine block has to be a 350, somewhere on the engine block should say if its a 5.0L or 5.7L (I think... I cant remeber, my brain is fried from work) anyway, a 305 is a 305, and a 350 is a 350... nothing can change it unless you get a 350 block to consider it a 350, and get a 305 engine block to consider a 305.

350's make more power (as what im told by people here) and 305 dont...

 

350 has a larger bore diameter. You CANNOT make a 305 into a 350. Not enough material there to get the bore to the correct size.

Changing the cam and heads does NOT change the displacement of the engine, at all. Displacement is determined by bore and stroke, neither of which is affected by the cam or the heads.

 

Starters are the same.

Some of the cams are the same.

305 heads had smaller chambers than 350 heads, and smaller valves than some 350 heads.

 

is it really? (its a real question, I dont want it to sound like its being rude, lol)
people tell me the 305 starter will work for a while, but it will eat up your flywheel and some other parts, and end up taring out the whole engine and replace parts, so its just better getting a new starter...
taking that's wrong?

 

You need to stop listening to those people.

 

alrig thats wat i thought...this guy is pretty knowledable about chevys. He said thats wat GM did. I didnt think it was true tho. I know the displacement has to do with the bore diameter and the length of the stoke. I didnt know if the bigger chambers of the 350 could give you 45 cubic inches or not. Seemed kinda far off but w/e. I guess he was wrong about it. Thanks for the info!
----------
im a 16 year old with a 305 also. I know that a 305 is a 305 no matter how many 350 parts are on it...i know it is a 305 for sure. Im about to put a used borla cat back on it with headers and an empty cat..getting it all for 620. Everything im getting is like 500 miles used. Pretty sweet deal considering the cost of borla brand new

 

Chevy has made the small block in various bore sizes over the years, from as small as about 3.5" (267 in the late 70s) to 4.125" (400). Similarly, there have been strokes from 3" (265, 283) up to 3.75" (400). All the blocks for all these sizes are the same external dimensions. All heads from all engines will bolt onto all blocks (up until the LT1 in the 90s). The same cams fit them all, except that factory roller cams can go only into blocks that have the retainer plate provisions (87-up). The same starters fit them all, within certain year model (NOT size) restrictions.

Many of the parts can be mix-&-matched to make sizes Chevy never did. The 383 is one such combo that's particularly popular.

The 350 has a 4.000" bore and 3.48" stroke. The 305 has that same stroke, with a 3.736" bore. There is no way to turn a 305 into a 350, except to bore the entire cyls out and replace them with sleeves; but this would cost SEVERAL times as much as going to the junkyard and just buying a 350 block. So while it's possible to turn a 305 block into a 350 one, it's FAR from practical. I've never seen or even heard of it being done; although it's something somebody might be tempted to try in circle-track racing if there was a class with a "305" rule, as long as it wasn't a "claimer" class, since getting "claimed" would pretty much invalidate the value of doing all that.

Blocks have a casting number. That part # will tell you what the bore size is. Not necessarily the engine size, as there are many sizes that can be made out of the different bores. For instance, Chevy supplied motors with 4" bores in 302, 327, and 350 CID, using the same block casting numbers in some cases; and out here in aftermarket world, those castings can also be used to make a 383.

"Chambers" are part of the heads and don't affect the engine "size". Again, there's considerable variation in this over the years; from the smallest at about 58cc, to the largest at about 76-80cc. Among heads with the same chamber size, there can be an ENORMOUS variation in other parts, including intake port size and design, valve size, presence or absence of various accessory bolt holes, etc.

 

alright thanks man thats cool lots of info. just gave me that much more