Well let me start off by saying that im going to have a lot of questions since i have never built a motor from the block up.

I am getting a 5.3 block that has been bored .030 over for a very good deal. I am going to be building this up as a low compression FI motor. I believe that i will use a stock 5.3 crank because they seem to hold up just fine. One thing im not sure about is the piston size. I do not know the stock 5.3 bore or what is is now that is has been bored out .030 over. So i need to know what size piston to go with.

I also belive that the stock rod length is 6.125" so i can just get a good forged rod with those measurements since im keeping the stock crank.

I need to know more about compression on this motor. I would like for it to be around 8.75:1 or so. I plan on using some 317 heads and i believe the combustion chambers on those are 72cc, so i need to figure out the dish(or no dish) on the pistons as well as the head gasket thickness.

I have many more questions but this will be a good start.

Thanks,

Mark G

 

Also, what would the displacement be with the new bore, in the 330s or something..Please dont tell me that i have to get custom pistons.

 

I did some calculations real quick(have no idea if they are right) but I believe that a 5.3 over .030 would come out to be 3.809.

 

you will have to special order a set of pistons.
any thing available that you can just order for a 30 over bore will give you a
low 9 on comp, that's with the 917 heads and gasket of chouse.
to get in to the 8's your looking at a custom set to be made for the 5.3

 

are you saying that ill have to order a special set no matter what compression I decide to go with, ill be happy with low 9s if i could pick up a set off of the shelf.

 

might wanna just jump up to 5.7 bore. It would be cheaper on pistons.

 

is that bore 3.90, also, how much is it to get them bored out like that.

 

same price to punch out a block, does not matter if your going 010, 030, or 090.

 

yeah i just didnt know how much it was to bore it out, the block im getting is already been machined, i was also curious how much these 5.3 blocks could be bored out.

 

you can turn a 5.3 in to a 5.7 if you had a good used set of LS1 pistons.