diffrence between a 305 sbc and a 350 sbc?

Question

Ok so here it is I got a 78 monte carlo about a month and a half ago because the cutlass was taking up to much money and time so it will have to wait for a little bit. But anyways I got a 78 monte carlo for 1000 bucks. its pretty nice body was in fair condition along with paint engine ran good but smokes a little. interior is decent but needs some work. But the main thing Im curious about is whats under the hood the owner did not want to get rid of the car at all so I didnt ask anything about it so he wouldnt change his mind. but the engine has an rpm performer intake,carb maybe a cam not sure. no headers dont know why but they kept exuast manifolds and a custom exuast set up. I was wondering if it was the original engine or if they swaped it out any idea how to tell the diffrence between an 305 and a 350?
http://www.cardomain.com/ride/2750677
Heres a link of the car if anybody wants to see it or the engine.

Answer 1

OK I would say that this is not an original engine but it looks like you have a SB 350CID. your Monte looks like a LS model which means that it could have 1 of the optional engines in stock form when this car was new. Who ever added the racing parts could have known that this is a 4 bolt main 350CID.

The differences between a 305CID and 350CID is the 305 was very hard to get HP out of, the bottom end on a 305 has 2 bolt mains bearings and was engineered for economy, cruising and long time drive ability while giving you some v8 get up with out burning a hold lot of gas.

The 350CID well you see it everyday and the basics of a 350CID is the same tech that the LT1s LS2-6s are based on in your VETTS,SS CAMARO, TRANS AM,GTOs and every signal CHEVY / GMC TRUCK AND SUV that are on the road today. THE 350CID is one of the most bad az v8s in the world and is easy to get HP out of and the aftermarket parts are FOREVER on it. The 350CID stock bottom end if its a 4 bolt main can handle up to close to 500hp with out any major rebuilding or giving up reliability and i say that because GM did make a 2 bolt main 350CID also.

check out HOTRODCHEVY.com
and SUPERCHEVY.com

Answer 2

65 chevy HD with a 350, if it's original engine well maintained 8-ish 72 Z with a 305, same conditions 15-ish The truck is probably around 3 tons, and the car around 1.5, plus the aerodynamic properties are WAY different between the two, but you're still talking carburetors, and even the slightest mis-adjustment can cause MAJOR changes to MPG. There's also about 10 million variables that make this hard to guess at. The Z might have had a huge cam put in it (more power, less MPG), had ignition upgrades (better MPG and more power), and countless other things. Both stock and properly tuned though, twice the MPG for the Z is a fairly good guess "off the cuff".

Answer 3

In 1978 the standard engine was the 350..... the 305 was availble as an option engine coming with a whopping 140 HP.... why would anybody with more than 2 brain cells opt for the 305 in this case?? Hopefully you have the 350.... well if you floor you car and it takes 20 minutes to get to 60mph then you have the 305....

Answer 4

One way to know if it is a 350 or 305 is to look for the casting number on the block,they will be stamped onto a tab that is cast into the block this tab or plate is located on the right side on early model blocks and on the left on later model blocks the tab is cast into the block in front at the deck of the block (where the heads bolt on)close to the water pump.Take these numbers to any GM dealer or local garage and they can look them up in a Haynes interchange book and tell you the C.I.D. of your engine and what that engine was available in also the rated horse power of that engine. If it is a 305 its not all bad with a set of after market heads you can make a 305 move pretty good still there is no replacement for displacement,but the Chevy 283,302 (Yes Chevy made a 302) and the 327 are smaller C.I.D. engines and they make alot of power

Answer 5

As this is right around the time of the gas crisis this may be a 305, if you are actually getting the horespower and performance numbers you are bragging about on your site, it most likely is a 350, the HP figure is similar to what a good 350 puts out in the Mid range although nothing seems to match from the pictures so there is no definitive way to know for sure as the 350 and 305 share the same block envelope as well as the same mountings in most cases.

Answer 6

Casting numbers or look at the starter the 305 starter is usually smaller then the 350 starter