I am re-doing the top-end of the car. I have LT4 heads and intake that are being ported and polished. I have the xe 230/236 cam and will be using 1.6 rrs for a lift of .544/.555.

I found out after the car was torn down that the block has been bored 0.30 over. This makes it a 355.

Now, heres the problem. The guy who is porting and polishing the heads and intake is saying that the pistons need to be shaved or there will be a collision between the piston and the heads? Something to that effect.

What gives? I need immediate info so I can plan a course of action.

Thanks in advance.

 

hes full of it.

bore size has nothing to do with piston to valve or heads contact.

everything should be ok, still probably want to check the clearance. i didnt on mine and it was fine.

 

As a general rule, it's always a good idea to check piston to valve clearance. However, many people are using cams with this kind of lift in LT1's without a problem. That said, you didn't indicate what pistons you are using. But if they are nothing out of the ordinary, you are unikely to have a problem.

Rich Krause

 

all i know is that they have 4 valve relief and say 0.30. no more info

 

check to see if they blocks been decked,
I think i was told to take a head off put some kinda of puddy on the the piston, put the head back on turn the motor over, take it back off and measure the clearence.

im sure some could explain better