L92 heads on a 5.3? [Archive]

dropped72ss

03-13-2010, 05:52 PM

I was wondering if the L92 heads are a direct bolt on to a 06 5.3? What kind of horse power numbers can i expect to see with these heads and a matched cam? Thanks

CliffsBlueCamaro

03-13-2010, 06:13 PM

Unfortunately, the L92 heads will only fit on engines with a 4.0" or larger bore because the valves will contact the cylinder walls. I'm pretty sure the 5.3/4.8 can only be bored out to just over 3.9".

While we are on the topic - can anyone explain why the 5.3 can't be bored out to 4.0"?

WS6

03-13-2010, 07:14 PM

L92 heads on a 5.3 would be way too big even if they did physically fit.

Honestly, I'm not sure why you can't bore a 5.3 to 4.0" other than maybe cylinder wall thickness perhaps.

69cutlassrkt

03-13-2010, 08:18 PM

mast motorsports has 12 degree L92 heads for a 3.9" bore

Memphis

03-13-2010, 08:40 PM

3.905 is the biggest you can go with the 5.3 iirc.

dropped72ss

03-13-2010, 10:09 PM

ok, thanks for the info guys! I really would just really like to get a little more power out of my little 5.3. Its got very low milage and i'm just looking to get a little more pep out of it.

Rick Dorion

03-14-2010, 03:28 AM

I'm too lazy to find it but Steven Rupp did a nice 5.3 build!

andrewb70

03-14-2010, 09:45 AM

.....I'm not sure why you can't bore a 5.3 to 4.0" other than maybe cylinder wall thickness perhaps.

Bingo...

Andrew

TGVettes

03-16-2010, 08:17 PM

I'm building a 5.3 for my 63 nova now. I call it LS327
I'm going to use cnc ported stock 5.3 heads. I would say that just a set of nicely ported 5.3 heads and headers would give you a nice horse power gain. Cam does a lot for the 5.3 performance to.
I'm looking at getting about 450 horse out of mine but that is a build engine with pretty much everything tweaked.

Tonny

93Polo

03-17-2010, 06:51 PM

I'm building a 5.3 for my 63 nova now. I call it LS327
I'm going to use cnc ported stock 5.3 heads. I would say that just a set of nicely ported 5.3 heads and headers would give you a nice horse power gain. Cam does a lot for the 5.3 performance to.
I'm looking at getting about 450 horse out of mine but that is a build engine with pretty much everything tweaked.

Tonny
Send the 5.3 heads to TEA www.totalengineairflow.com (http://www.totalengineairflow.com) I had a set of their stage 2s on my C5. The 5.3 heads actually flow better when ported than ported LS1 heads and would have better velocity than the L92 heads. 450 on the flywheel should be no problem with a 5.3. If it were mine 224cam, TEA stg 1.5s (same as a stage 2 but stock exhaust valve which flows better than the bigger aftermarket valve) and a LS6 or LS2 intake for a budget build. As mentioned above Steve had a nice 5.3 build.