Help with 5.3 Engine build in rock crawler

[kerrige]

It needs to be kept in mind certain conditions. Are you talking about crank power goals or to the wheels? How tall are your tires and gears? If you are going 2800 stall then a 220/224 would be a good choice for something a tiny bit bigger. Anything larger than 224 is going to move the powerband up too high for your desires. Keep the LSA low around 112. A split duration cam will open up your power a bit wider so it comes in sooner and ends higher. I would take about .030 off the heads for a nice bump in power. 400 to the crank is possible. 350 to the wheels can be done.

[Bodie]

A crawler is a very different animal as far as trying to figure power for. Honestly I don't have to have off idle power due to all the different ratios I can run. I can run dual t-cases with low gears in them, also run low axle gears and I run a TH350 trans, so I have three gears there. The lower ratios I have available, the more gearing options I have. So say my lowest ratio is 120:1 I can run an engine that makes its power at 3-4k RPM and be totally fine because at 3k RPM ill be moving 5mph.

I just want the most power I can have without running a really high stall.

Its got 42" tires, 4.10:1 axle gears, and will run a stock NP205. If I need more gearing, Ill add a doubler, ect. The thing is, with more power I don't need such low ratios, and can hit obstacles with momentum and wheel speed instead of crawling the best line. I'm more of a mat it and close your eyes kind of person, than a technical driver. I think its more fun my way. LOL

[Bodie]

I am talking flywheel HP.

[Bodie]

I would take about .030 off the heads for a nice bump in power. 400 to the crank is possible. 350 to the wheels can be done.

Granted its degreed correctly, do I need to worry about piston contact with the flat top pistons and a larger cam that meets my goal, sub .600 lift? Any guesstimate, maybe from similar setup as to what CR would be?

[kerrige]

Max lift how aggressive the lift milling and more is going to Effect PTV issues. I wouldn't be surprised if it became an issue at 600ish lift flattops and milled heads. You may need to fly cut piston reliefs or go will a lower lift cam. In order to be in the power at 3000 rpm I would imagine you would need to keep the duration below 224. However, utilizing a good split will sacrifice peak power for a wider power band. A 222/226 .591/.598 LSA111+3 would be a fantastic cam matched to a 2800 stall. Lots of mash able power and the compression will keep the torque strong out of the gate. There is no magic combo however about 11:1 compression with everything else should make for a very fun setup. I could see a setup like this producing over 400@the flywheel.

[Bodie]

Will the stock rods handle 11:1?

[kerrige]

Will the stock rods handle 11:1?

Should do just fine, however, LS2 style rods would be better and are cheap. Arp rod bolts are a good idea.

[Bodie]

I tore the engine down today, looks like I am going to need to have it bored. I couldn't run a 6.0 piston could I?

[jansen]

No, but it can be bored to ls1 specs which would make your 400hp goal more attainable. A high compression ls1 would make 400 pretty easy with the right cam and a little port work.

[Bodie]

Is that .030 over? What are yall porting on a mild job? Port matched, or bowl work?