Help with 5.3 Engine build in rock crawler

[Bodie]

I need to rebuild my 5.3 I got for my rock crawler, and wanted to get some advice on what all I can and cant do with my budget. I would like about 400hp but more is always better. I would like to use alot of the stock parts to keep down cost and availability.

What is the limit for the stock rods? I would like to add a bit of compression and possibly run it on E85. I figured decking the heads, and maybe some good pistons could get me to that limit.

Also, what camshaft would you guys recommend? I cant run a really high stall converter due to overheating issues and its just a pain to build alot of RPM to make it over stuff. I need to be able to be on and off the throttle alot, and I will have a big cooler with fan.

Would I need to run larger injectors for the E85? What about the fuel system? Can i just use a Walbro pump for 400hp on E85?

I appreciate the help guys, this is what its going in...

[bstill]

You can use 4.8 flat top pistons for the bump in compression. Stock rods will be fine. Get some ported 5.3 heads milled to around 60cc. The bump in compression will help your low end torque. A cam around 220 duration will be fine with a stockish stall. There's really no need for e85 unless you really want to run it and larger injectors would be needed. You'll need to upgrade your injectors for best results anyways, even with 93 octane. A Walbro 255 will work for your goals.

[kerrige]

A stall around 2600 and a cam calling the lines of 216/230 would go great. Upping the compression to around 10.5:1 is a great idea. Mill the heads anduse 4.8L flattops. I wwouldn't expect 400hp out of a 5.3 however big off throttle torque is totally what you want and can get. If you plan on staying NA then a walbro 255 should be fine with 42lbs injectors and your good to go. Even with E85 I would imagine 42s and a 255 would be fine or maybe a 340 to be safe.

[EmmerichLSx]

Call Texas Speed they got my buddy set up for his ls1 in his crawler.

[Slow04xcab]

212/218 low lift cam had great low end in my 5.3. Ran it for a bit with stock stall. I wouldn't go much over 220 duration cam choice with lsa of 112-114.

[Bodie]

I appreciate the info guys.

So it would be a stretch to get 400hp out of a 5.3 with just a cam and bump CR? I thought you could get 100hp with just a cam swap?

I assume the stock injectors are 42lb?

[Bodie]

repost...

[Slow04xcab]

Stock wouldn't be 42lbs...400hp at crank yes not that hard. 100 from a cam swap only would be a stretch. Haven't ever seen it happen. With more aggressive cam you could get more hp but would loose too much low end for your plan. Plus have to run a nice size stall to take advantage of the power band.

[Bodie]

Gotcha, thanks!

So what about a TSP 220 .581 112lsa? Or could I go bigger? Id like to stay at or under a 2800 stall.

[Bodie]

Would anyone how much I should take off the heads?