hi there I have a 84 Camaro Z28. it has the 305 in it and I know I can bore it to a 350. but I was wondering if I could go from 305 to 383 without any problems. or if I would be better off finding a 350 or a 383.

 

You "know" the 305 can be bored out to a 350, have you done it before with success?
The 350 has a 4" bore. 305 has a 3.736" bore. That's an overall diameter difference of .264", which is more than 1/4". Or more simply, .132" removed from the wall thickness. You might find a 305 block that has a wall thickness of .150", which would leave you with a paper thin wall of .018. Going under .100" wall thickness can be pressing your luck, .018 won't make it around the block before the walls blow into the water jackets. In case you didn't guess by now, you want to start with a 4" bore block to do what you're after.

 

Never going to happen.....Boring out 305.

 

Waste of resorces. The 305 main webs in the block are weak. GM designed the 305 in the 70's when Low compression forced low HP and the engeer design the 305 as light as possible. No matter what parts you put in it the bottom end will always be weak.

When they did the TPI 305 we saw a lot of spun rod bearing under warranty. I never saw a spun rod on a L98 350. When I asked a GM engineer at the GM Pittsburg tech center he said flat out the 305 casting will never have the strength. Most likely the 305 we saw failing under warranty were casued by casting defects but the TPI 305 was concidered the limit of the 305 block. What he ment was not every 305 block with have an issue with 275 HP but not every 305 block could handle 275 HP either.383 are torque monsters. "If possible" a 305 turn 383 would just be a grenade with the pin under your right foot.

 

Lol. Impossible to make a 305 a 383 like Camaro 69 says. A 383 is made from boring AND stroking a 350. Who told you that you can bore a 305 into a 350? Because you shouldn't be taking any mechanical advice from them anymore. When people say all SBC's are the same, they are referring to what you can bolt on to them. Like stated above the 305 has thin cylinder walls and a long stroke already. I doubt there is much room to stroke it out any further, if it is even possible.