any easy way to tell 350 from 305

**Krazy351w** · 06-08-2007, 05:23 PM

i got a guy trying to sell me an engine saying its a 350 but my friend tells me that its a 305 and a waist of money.

**mrr23** · 06-08-2007, 05:34 PM

casting number on the back of the block behind the driver's head on the bellhousing mount pad. then, go to www.mortec.com and look it up.

**smallblockhero** · 06-08-2007, 05:34 PM

by lookin at it?..um no not really. unless you know casting numbers. is it out of the car? GEN I's all are externaly the same dimensions and share parts so its hard if you dont know what to look for.

**Krazy351w** · 06-08-2007, 05:36 PM

its not in anything. the guy said it came from either the 80 model vette or mabey a truck and that its a 350tbi but my friend said its a 305 cuz the valve cover bolts go down the center.

**mrr23** · 06-08-2007, 05:37 PM

Originally Posted by Krazy351w

its not in anything. the guy said it came from either the 80 model vette or mabey a truck and that its a 350tbi but my friend said its a 305 cuz the valve cover bolts go down the center.

they do on 350 motors as well. called centerbolt valve covers. started around 1985.

**Krazy351w** · 06-08-2007, 05:39 PM

thats what i thought because my 92 rs has a 350 in it and its like that and im almost positive its a 350 because it runs a 13.6 E.T. and all i have done to it is regear. i Know a 305 wont run that well.

**mrr23** · 06-08-2007, 05:42 PM

Originally Posted by Krazy351w

thats what i thought because my 92 rs has a 350 in it and its like that and im almost positive its a 350 because it runs a 13.6 E.T. and all i have done to it is regear. i Know a 305 wont run that well.

well that wouldn't be a factory 350 in the RS as they only came with 305 TBI from the factory. someone swapped the motor out. a 305 can run that well. just takes some really good work.

**Krazy351w** · 06-08-2007, 05:45 PM

o i knew it wasnt a factory engine. liek i said im just really sure its a 350 due to how well it runs, considering its bone stock. any ways ill look up the casting numbers and hope its a 350. also i will be rebuilding my engine in the RS soon. what all should i have done to it to hop it up some. id like to get at least 350hp

**AKIRA** · 06-08-2007, 05:46 PM

Originally Posted by mrr23

well that wouldn't be a factory 350 in the RS as they only came with 305 TBI from the factory. someone swapped the motor out. a 305 can run that well. just takes some really good work.

I was going to say the exact same thing on both counts.