02sierraz71_5.3

iTrader: (2)

Thats a good idea I think thats what im missing. Any other ideas.

gonzo 6.2

iTrader: (8)

See this is totally my fault and my mistake.i thought you wanted to know how to get to 350HP and run quick ETs on a budget.I cant help you because i havent been able to make a 5.3 run on a budget in a xcab 4x4 but only in a rcswb 2x4.

F8L Z71

You are losing power somewhere... Your timing is much too low for an N/A max effort setup. Did you guys check for piston to valve clearance before installing everything? Milling the heads heavily and using a high lift cam with a fast ramp rate can easily cause issue, especially if you use weak springs. On my T/A I went to far and although I ran decent for my mods I was still 3mph short of my goal. Why? because my valves clearanced themselves on my pistons .

I made 304rwhp with a cam and headers on my 5.3L without tuning. After tuning I gained 3+mph (14.29@97mph) so I can only assume I gained 20rwhp or tons more area under the curve. You could possibly have more in there if you work out the bugs and get a good tune. You need to check and ensure your pushrod length is correct also. When we did mine we had to go to short pushrods and even then had to add shims to get everything correct.

Your 5.3L should be able to achieve 350rwhp with high compression heads and the correct cam. You just need to have the right combo and execute it correctly. IE you can have all the right ingredients and still **** up making a cake. LOL

02sierraz71_5.3

iTrader: (2)

I never said it was your fault?
All I asked for was advice on a 5.3, so Ive got alot to learn I know this thats why Im on here searching. Now lets make this ******* thing run

02sierraz71_5.3

iTrader: (2)

Im ******* up the cake somehow obviously.
I had smaller pushrods .735 and alot of valve noise, I put 7.4 back in and less noise. My valve geometry is all fucked up. I told my mechanic to check the p/v clearance he said " I turned it over by hand and didnt hear any problems" which means he didnt actually check it. I think Randy might be onto something with the adjustable rockers and shims. Ive still got the stock heads Id just need to put springs in them to run with cam. My current heads have 918's. Im going to buy a pushrod length checker and Im looking into the adjustable pushrods. I can do all this myself in the parking lot.

So my choices now are
a) put springs in stock heads put them back on?
b) Try and fix the heads that are on with, shims, adjustable rockers and check for proper pushrod length.

which would you guys do and do you think I can make the geometry right with the current setup/is it worth it. I hate giving up on these heads I have now its almost like quiting which I will not do.

thanks for all the help!

gonzo 6.2

iTrader: (8)

02sierraz71_5.3
TECH Apprentice Join Date: Oct 2004
Posts: 351

5.3 to 6.0 swap

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5.3 to 6.0 swap what did you pay and where did you get it from. Alot of people are saying its cheaper to do a 6.0 swap with a cam then to do heads and a cam on a 5.3 Im just wondering where I can get a 6.0 for that cheap, under 2k.


these are your words

02Reaper

iTrader: (2)

I am going to give you some advice that I have given plenty of times before and have researched well into myself. Number one is that the 2" intake valve you have in there now is killing you. It is just too much for the 5.3 bore which is 3.78 compared to 3.89 (5.7) and 6.0 liter engines. The stock valves are already shrouded in the 5.3 heads because of this smaller bore, if anything you need to open the chamber up to the 5.3 gasket size to unshroud them. Number two is that I dont know who ported your heads and I dont know what they flow, but you also dont need a head that flows 300 cfm on the 4.8/5.3 motor. That is just too much. Milling heads for compression only adds minimal gains. Making an engine have power and efficiency is like putting a puzzle together. you have to match the parts or it wont work very good at all. to get all of the potential out of your motor you will need to get all of your parts matched for that motor. Just because you can switch parts on the 4.8/5.3/5.7/6.0 doesnt mean that they will all act the same to the same parts. Just because it works on the bigger motors doesnt mean that it will work good with ours. I think that Allan Futral at Futral motorsports is the only one who realizes this. I have the dyno charts to prove that the 5.3 is well capable of around 400 hp and Tq to the rear wheels, but I am not going to get into that boat because I dont want the headache of explaining over and over to the BS flags that will be raised.

02sierraz71_5.3

iTrader: (2)

What was the setup of the 5.3 to get 400 rwhp NA?