69MyWay

iTrader: (2)

I did a search on "5.3" heads, but I think it is too broad.

I am trying to find out what the deal is with the 5.3 and if they are a good alternative for the 5.7 engines. I am getting ready to build a more or less nearly stock LS1 for a 1985 Corvette project. I picked up a 5.3 complete engine today as well and was wondering if I should run those heads instead.

What is the plus and minus of this swap as a stock bolt on?

Are mods needed to do the swap?

My 5.7 heads will need to be re-worked anyway...so I am just curious how these work?

91_RS_LS1

As far as I know, the stock 5.3s have a smaller chamber than LS1 heads, but flow less and have smaller vavles. The 5.3s most people run are ported. Texas Speed and Performance, Patriot, etc. I plan to buy a head/cam kit from Texas Speed. 5.3 heads, and not sure on the cam yet. Hope this helps.

69MyWay

iTrader: (2)

I have heard many people talking about using them. I guess that is only in the modified form? It sounds like you can get more compression with them.

Any other benefit?

91_RS_LS1

I've never heard of any one bolting on stock 5.3 heads onto a LS1. Not saying that no one has, I've just not heard of it. I don't know the exact flow, but other than more compression, I don't think there would be any advantage. The stock 5.3s have smaller vavles than the LS1 heads (at least I think).
As for other benefits, the aftermarket CNC'ed headsflow around 300 cfm. But, you have to worry about piston to valve clearance with some of them.
I'm not sure on the stock advantages/disadvantages, so I'd advise you to do a search.