chevydad

i'm putting one of these in my car, it will have the edelbrock carburated intake on it and a holley 700dp. my questions are:

1. which would be the desired heads on each motor(would a 5.3 head or ls1 head be better on the 6.0 and vise versa on the 5.3)?

2. i'm looking at putting a pretty big cam (trex or magic stick cam) in the 5.3 or 6.0. asumming all things are equal, what would the hp difference be between the two motors.

dropped4dohoe

I have a 6.0 block bored .030 over with a pretty nasty cam and a set of stage 3 5.3 heads on my carb set up. Car runs awesome. The 5.3 heads will give you more compression which works great an the carb set up.

I would deffinately go with the 6.0 even though the block will cost a little more to get cause the torque will be awesome with the carb set up. I would say go with the 5.3 heads if you are planning on having some port work done. if not you would probably be better off with 5.7 heads cause the runner volume is a little more although the compression ratio will drop slightly unless you mill them down. HP difference between the 5.3 and 6.0 might be around 15-20 difference but the torque will be much, much greater with 6.0 block.

chevydad

i wasn't planning on doing any porting, but i could get the heads milled. so the ls1 heads would be better milled than stock 5.3, but ported 5.3's would be best? what is wrong with the 6.0 heads? and the purchase price is the same on the motors, the 6.0 is a high mileage 200k motor, and the 5.3 is a low mileage 60k. i would probably try to throw in some new crank and rod bearings in the 6.0 maybe new rings nothing more.

dropped4dohoe

If they are the same price I would deffinately go with the 6.0 because when we get motors, low milage or high, we still go through and freshen them up. The 6.0 heads would probably be ok but I would probably mill them at least .040" to get the compression up, but they are aluminum right? The 6.0 heads have a pretty large runner volume which works well top end but you wont have as much low end, but by bumping up the compression it will help it out. Bearings and rings are good but you might wanna go ahead and get you a new oil pump as well(like a melling HV). But I will tell you one thing, the carb set up works bad ***. I had a Divinci 750 on it and it just spun from a stand still through the end of third gear (TH350) and that was with a stock converter. Let me know if I can be of any assistance cause I really like those set-ups.

chevydad

i plan on using the th350 also, with a 3500 stall convertor. are you using the edelbrock intake and the msd ignition with it? which timing pill are you using?

i haven't seen the motor yet, but i'm kinda thinking it was from a 99 truck, don't they have iron heads? any difference in the heads besides weight?

dropped4dohoe

Yeah Im using the performer intake right now with a curve 4 chip in it, but I might swap out to the Victor intake cause I wanna spin a little higher RPM. thee is a pretty big weight difference between the alum and iron heads but im pretty sure thats the only difference.

whitt1

Late model 6.0 heads are a 317 aluminum castings with porting similar to a LS6 and 72cc combustion chambers.The only advantage the 5.3 heads have is a smaller cumbustion chamber at 62cc,the 317 6.0 heads will outflow the 5.3 heads by a considerable margin.The horsepower difference between the 6.0 and the 5.3 is more like 40 to 50hp.If you want more compression mill the 6.0 heads.The 5.3 heads also use a 1.89" intake valve vs.a 2.0" in the 6.0 head.

TurboBerserker

iTrader: (1)

I agree with Whitt1 on the heads. I believe the intake runners on the 6.0L heads are 210ccs or something like that -- plenty of runner volume anyway. Its true that they have 72cc chambers, but some flatops will cure that... In fact if you get an LQ9 long block (or short block and find some 317's) your compression will be 10.1:1 with the stock flattop pistons.

whitt1

I would avoid the early model 6.0 with CI heads,it uses a different crankshaft flange that only works with a 4L80E transmission.Pass on the 99 model 6.0.

chevydad

are you positive on this? i plan on using a th350, and the hub spacer.