Youngblood16

I have a 2001 5.3 out of a suburban. It has 706 casting heads and im looking to get the max performance out of it, I will also be putting in a 224r or stage 1 cam from tick, maybe have Martin spec me one, I don't know yet. Anyone have any STOCK GM heads, 241s 243s etc that would be optimal to put on for cam only performance? Not trying to spend too much on heads but I don't want to go to big either.
Thanks Guys

HCI2000SS

iTrader: (2)

Why not not have those 5.3 heads worked over since you already have them? Mine have been worked over by Texas A Speed and they pretty good

Darth_V8r

iTrader: (4)

I could see swapping for 243's but why would you swap 241's in? You could change your head gasket thickness to get the same benefit, right? 706 and 241 flow the same. Chamber volume is the only diff

Youngblood16

Honestly I have done no research yet on the 706s and I just figured they were poop. Should have done the investigation work first.

Love your sig btw V8r

Darth_V8r

iTrader: (4)

Thanks! 706's are good factory heads. The 04-06 years had a porosity issue from one vendor, but you're an 01, so probably safe. I've heard of guys putting 706's on the 5.7 to raise compression.

Like HCI said, having the ones you got worked over is a good bet for performance. If you are wanting to stay bone stock, stick them back on

Youngblood16

Well I wouldn't necessarily say BONE stock, I just figured aftermarket heads are more designed for huge airflow and I wont need that for the street friendly daily cam (Stage 1 or 224). I just figured if I could bump the compression and port them a little they should be just about what the doctor ordered. I was really looking at the TSP 2.5 5.3 heads but figured they would be too much air. Any more thoughts?

whatsa347

iTrader: (6)

Never can get too good of a head for these cars. A good set of heads does everything better.

Youngblood16

But if I get too large of a port/intake runner then I could potentially lose power, right? I just spoke to the man who would be doing the heads, he said it would be about 1200 to recut the head for bigger valves, and do bench flow testing style porting, but doesn't include parts such as new valves, seals and such so I would probably be looking at around 1500 for it all. Does anyone suggest any castings I could buy for that much or would be better and potentially be a cheaper alternative?

bbond105

Trickflow 220cc As Cast Cylinder Heads from Vengeance Racing for under $2k.

KCS

iTrader: (20)

I would just have your cylinder head guy cut the valvejob for larger valves, open up the throat, and then blend it all in. It'll probably cost you 1/3 the price he quoted you and you'd see 90% of the gains.

If you have $1200 in the budget for upgrades, pull the 5.3L and swap in a 6.0L instead. The extra 40 cubic inches will be a much better bang for your buck than ported heads.

Youngblood16

He said the only thing he would do would be to open up the bowls, run it on the flow bench to assure the same flow numbers per cylinder, then cut for the big valves. he said he probably wouldn't mess with the runners because it wouldn't really be for street use. that's only labor, and its 1200.

KCS- This will be a daily and I am also looking for a little bit of gas mileage, how much do you think my mileage will be affected if I switch from a 5.3 to a 6.0

KCS

iTrader: (20)

Damn, that's a lot of money for that little amount of work. Cutting the valvejob and bowl work shouldn't be more than $500 max, and even that is steep. Forget that guy if that's how much he wants. If you can't find someone more reasonable, send them to AI for their "performance rebuild". They'll disassemble and clean everything, cut the valvejob on a CNC machine, grind the valves, mill the deck, and reassemble for $500.

It's hard to say about the mileage since the cam has still yet to be chosen, but it really shouldn't be that bad. In my car, I gained about 30ci and 100lbs going to the iron 6.2L, and I didn't really notice a change in mileage, but I do have a T56 behind it.

Youngblood16

mine will be t56 shifted too, its going into an s10. Nothing like rowing some gears.

Should I go iron block or try for a cheap LS2?

HCI2000SS

iTrader: (2)

If you can get a LS2 cheaper than a iron block setup then I'd go for it, otherwise not

Youngblood16

What do you guys think would be better, the 706 heads or 853 castings that have been decked 50 thousands and ported?

Darth_V8r

iTrader: (4)

If the 706 is stock and the 853 is ported and decked, go with the 853. You will want to verify PTV clearance with that much milled off. If they are both worked on, it probably makes very little difference

redtan

iTrader: (5)

$1200 for just a valve job and bowl work?

You can get fully ported 5.3s with all that (including the castings themselves) for cheaper from places like TSP.

And there's nothing wrong with messing with the runners for street use. Plenty of people on here use fully ported heads or aftermarket castings on the street just fine.

babbage1109

iTrader: (11)

im running ported/milled 706 heads 12:1 comp on an 5.7. i only had them milled around .030 and running a .040 head gasket. pistons are flycut for safety but still had plenty of clearance

Youngblood16

Im thinking ill stick with stockers until my funding recouperates then throw on the PRC 2.5 5.3 heads and cam package. maybe shave the stock heads while the engine is getting rebuilt, no doubt this wont be cheap.

HCI2000SS

iTrader: (2)

You can get the PRC 5.3 heads from TSP for like $1200. That's your best bet