I got a question here hopefully someone can help. Im going to run a stock LS1 block with a 224/224 581.581 113. I want to put 5.3 heads on the block will I need anything other then the stock stuff I have?

 

You need to open the chambers up to match your 3.90 bore and put at least a stock size LS1 intake valve of 2.00, I think the 5.3 head has a 1.89 intake valve in it.

 

Are they stock 5.3 or aftermarket?

 

Stock

 

I want to put a set of them on my 2002 firehawk. Is there anything I need to know that I may have to get to get these things to fit?

 

i didn't try it but i think they will fit without modification. you want to get a ported 5.3 set, right?

 

they are a direct fit, but a stock 5.7L for stock 5.3L swap is not worth the effort IMO

 

I thought 5.3 heads flowed the same as LS1 heads but the 5.3 were better for more compression. I just wanted to try a set to see what happens and I was wondering about the pushrod length. Do I need longer or shorter pushrods?

 

anyone

 

Stock 5.3l heads have 1.89" intake valves and a chamber setup for a stock 5.3l bore (3.78"). They flow slightly less than a stock LS1 cylinder head, but not by much.

If the heads are not milled, they will take the same length pushrod.

Jason

 

thanks