Been lurking on here for a few months, now. Great site, lots of info. My rig's a little different from most on here--tube buggy rockcrawler. Stock 02 5.3(DBW), C6 vette manifolds,2.5 to 3" 70series flowmaster(no cat)CAI, custom tune, Hughes built TH400 RMVB, Allison TC(1800-2000 stall),Atlas 4.3, 5.38's in 60/14 bolt, 42" Pitbull tires.rigs 4200#'s.
Been wrapping up the drivetrain swap and only have driven around the neighborhood. Actually still have 4.88's in the axles yet,need to install new gears yet.
My question for the experts is lowrpm torque. Bottom is a tad soft. Pulls hard top end(actually chirps 42's shifting to 2nd!)Gears will help. What about milling the heads for compression? How much can you mill?10.5? 11.0? Will it help? Worth the effort/cost?
Last question is cam. don't want to give up ANYTHING down low. If a cam was an option it would have to increase across the board for my intended use.
sorry long post and thanks in advance for the advice.

 

You can take 40k off the heads, will pic up some hp.. Are you currently running the stock cam???

 

I would mill the heads and install a 212/218 low lift cam. That should actually help your low end out quite a bit.

 

Stock cam. Milling 40 will give what compression?

 

Cool project

Whats the top speed you expect to run in this?

Reason I ask is because low-rpm torque is difficult and there are only a couple ways you will be happy:

1.) Gears. You know what you are doing with the 5.38s, but can you go any lower? Using a tcase for any further gear reduction?

2.) Bigger engine. A 6.0 swap or some other bigger displacement engine will definietly give you what you want.

3.) Blower. Roots style blowers really shine here, like the radix 112 or tvs1900, *** loads of torque off idle. I would do this personally.

I would also keep the stock cam and a low stall torque converter. Wouldnt bother with milling the heads, not worth it in my opinion.

 

I milled mine .050" with a .040 gasket, and only got 10.6:1. just compression, with a stock cam may boost you low end, but I dont know if I ever read of anyone doing just that. Most run a bigger cam with higher comp cause low end is higher with the added compression and you dont lose low end as bad. LSX motors love compression! try it and see, it will not hurt. also, having a low duration cam with higher lift, with a low LSA (110, 108, ect)will get you some better TQ.

 

I don't think that milling the heads will make an appreciable difference... at least not for the trouble and the cost associated with it. Bolt a 1900 blower on that thing and you'll have all the low-end torque you'll need.

 

On paper 42's w/ 5.38's @6500rpm= 150mph. With King coilovers frt and rear double triangulated pushing 17" wheel travel AND full hydralic steering with only one .75 swaybar behind rear axle...... that would be a hand full!!!
5.38 are as low as you can go in a 10.5" 14 bolt(which is spooled). Don't get me wrong, this combo is strong. During early test drives the pump in the trannys pump was only producing 60 psi so was acting like high stall convertor? Holy **** it ripped!! Briefly. Now with a fully built tranny hooking up it took the edge off the "hit" on the bottom.
Got the 5.3 in trade for parts other wise definitely would have gotten a 6.0 if I had to go buy a LS.
Well, we'll see how the 5.38's help. Again, this rig won't see alot of high range use(except duning this year).
The vibe I've gotten of this forum towards 5.3's is---good tune and run them. If you want more---6.0?!? End of the day it's still only 325ci.
Correct?

 

like a 214/218 .559/.562 111 LSA HT1 From SDPC! Sorry, I'm partial to this cam! I do concur with Eric tho. I wish I would have listened to him before we did my motor install. I would likely have had the heads milled .040" to get me around 10.5:1.

 

I meant how fast do you plan to drive it. With a blower you are looking at an easy 400ft-lbs below 3000 on a 5.3