Couple questions 5.3l with 5.7 build.

[albrntout]

1. Can I run a 5.3 block with a 5.7 head? I know it works the other way.
2. What is the right gasket for this in a booster application? A 5.3 or 5.7? And MLS or not. trying for Lowish compression (8.5) would be ideal, 10 is max I can take.

Rest of story:

I obviously have some ideas as to what I'm doing, I'm just not sure if the gaskets would overlap too much, and if that chamber change would make for impossible tune.

I tried a few searches but didn't seem to find what I was looking for.
I have a bunch of parts from my z days and decided to put a nice motor together for my 85 Blazer.

I am building an LS(something), I have from a long time ago some stage II heads for an LS1, a complete 05 5.3l iron block, and many other misc parts (basically 3 motors worth or more); All of this is stuff that has accumulated over the last 10 years, ran into this 5.3 for 300.00 with all accessories and computer couldn't resist.

The 5.3 is stock, I intend to put in an old TR224 cam, comp cams lifters, pushrods, timing set, katech oil pump, ls6 manifoild, 42lbs injectors, arp head studs. I will be hooking it up to a STS turbo kit w/ic re-piping for the truck. I think the only thing I'm going to have to buy is an adapter plate for the tranny. Truck is a k5 converted to 1 ton running gear 4.55 42in tires, 2400 stall looks like ***T but off roads great!(Had it since high school)

[mark21742]

take a rubbing or template of your 5.3 block deck and see if the valves in the 5.7 heads clear the cylinder wall.
if they clear I don't see why you couldn't use them, most people use the 5.3 heads with bigger valves on the 5.7 because the smaller chamber in the 5.3 head give a higher compression. for what you want to do it should work