Figured I would give an update. No wonder they charge so much to port cylinder heads. I have no idea how many hours I have into these so far. But both heads were rough cut. I have one head polished, and today I checked it for volume to make sure they were at least kind of consistent. All I wanted was to be within 1cc from cylinder to cylinder.




So all four of the intake ports on this head came in at 216cc. The exhaust is 78cc. Factory these heads are 211cc and 75cc. It probably won't amount to much. But it's the best I can do. I checked the chambers too just to make sure they haven't ever been milled. They came in at 65cc. GM lists the 799 head as having a 64.45cc chamber so close enough.

I polished as much as I have patience for. It still needs more but I just don't care enough. Its smoother then stock and light years better then the pictures of CNC ported heads I found online.





I got the valve seals in the mail the other day. I should have the springs in a day or two. So If I can finish polishing the other head and lap valves I might get these bolted on soon.

 

Update time!

So I got the heads on. Tonight I'm going to get the water pump on. If you have never done an LS swap into a C4 there are a lot of issues with getting the water pump to fit in the car. At least there is with an early C4. Not sure about the later ones. But I'll post some pictures of what needs done in case anyone is ever trying to figure it out.

So I love this stuff. I know it's a little controversial. But I'll give my reasoning.




So I didn't have any 6.0L head gaskets laying around. I'm not a fan of no brand gaskets. So I found these AC Delco's on Rockauto for a good price. I sprayed them with copper sealant. The reason is that this stuff really helps if the mating surfaces aren't 100% perfect. Being that I didn't have anything machined this is the way to go. I also like this stuff if you are changing a MLS head gasket and the block is staying in the car. In this case the block deck and the mating surface of the head were cleaned and sanded with a long plainer and 400 grit sand paper. I sprayed layout fluid on the surface of the head. This showed that there weren't any high or low spots.

A lot of people say you should never use an adhesive on a head gasket. Well I have used this stuff for years on MLS gaskets and never had an issue.





I don't have the rockers on yet. But I just had to see what it looked like with the valve covers on. These are just a set of truck PCV style covers that I put in a blast cabinet and then did a bake on epoxy paint.

 

Ok so onto the water pump. If you have never done an LS swap into a C4 there is a kind of unique issue with the water pump. Well two issues really. The first problem is the fittings on the pump that are for the heater hoses. They stick out way too far to get a normal hose on them. So my solution was to remove the pressed in steel fittings and then tap the holes in the aluminum housing with 3/8 and 1/2 NPT. Then I just threaded in a 90 and a street 45 with some barb fittings.

This is how I did it on my LS6 that's in the car now.




This worked well. I've had it this way for years now with no issue. Heater works great. Also since the housings are aluminum a cheap set of taps from Harbor Freight cut right through. You don't need to drill the holes at all. Just use lots of oil and go slow with a good tap handle. The brass fittings were from Home Depot and the barbs were from ebay.

So the second problem is the location of the upper radiator hose on the pump. The truck pumps I don't think could be used. I'll not 100% on that, and if someone has used one on a C4 please feel free to correct me. But it looks like with a truck pump the upper hose would hit the hood. So I went with an F-body pump. All my accessories are also F-body. Well that fits well enough. But the problem is that the port for the upper hose on the pump is on the passenger side. So you have to cross over the front of the engine with a hose to make it connect to a factory radiator.



So this works but it puts a lot of heat right under the air intake.

 

So this brings me to solution #2.

The only LS water pump I could find that puts the upper radiator hose on the drivers side is from a LS3 Corvette. So I got one from Rockauto The only issue is belt spacing. The LS3 uses Corvette belt spacing not F-body. Lucky for me ICT Billet sells spacers just for this situation. The one spacer has a threaded port for a steam vent. This way I don't have to drill and tap a hole in the water pump like last time.



These are the spacers



So I broke out my trusty Chinese taps and threaded the heater hose ports after I pulled out the steel pressed in fittings.



So the nice thing about an LS3 water pump is they have a plugged port on them. I'm going to use it for a gauge sending unit. I'm using another sending unit on the cylinder head for a fan controller so I don't have that as an option. So I pulled out that plug. It was 3/8" straight thread. I ran the 3/8 NPT tap through and now it's good to go.



So this is what it looks like bolted on.




Now hopefully I won't put as much heat right under the air intake.

 

So last thing for today was to start putting in rockers. I used my ebay pushrod checker, and it came out that with LS7 lifters factory push rods are fine. So I got one side done. The only weird thing here is that because I ported the intake runners there is a hole from one of the rocker bolts in each intake runner. This is really common on ported LS heads. All you need to do is use some kind of sealant on the threads of the rocker bolts. I used RTV Black.

 

Any corrosion worries with using a brass fitting in aluminum? There's got to be some galvanic action between the two, but I don't know if it's significant enough in this case to worry about.

 

^^^ I've been looking for aluminum fittings for my swap since brass is extremely reactive with aluminum, but the photos you provided look posted make it look OK. I wonder if the threads are corroded since the only time the two are reactive are when they are in wet conditions.

 

Well, the coolant temperature ECM sensors, heater hose fittings, secondary cooling fan sensors, etc., on the L98 aluminum heads and intake manifold are brass too unless I'm missing something. I'm guessing that anti-seize applied to the threads helps quell that galvanic action. I think it should be okay. If not, I'm sure someone here will comment / correct.

 

I guess I never thought about it. I did use lots of Teflon tape when I put them in there. But at the same time like ajp01 said how many times have you seen brass temp sensors screwed into aluminum cylinder heads? Every LS motor has one. But they do have some kind of sealant on the threads.

Something else too, I had always read that stainless steel also can have a bad reaction with aluminum. And in some cases be even worse than brass. The factory pressed in fittings were stainless.

 

caught up in your thread. love the work you are doing.

 

Thank you. I appreciate that.

 

I got curious and did some looking, so the reasoning behind the stainless tubes? Well stainless in the case of the water pump is the anode in the galvanic reaction, so the tubes themselves will be corroded, brass reverses this reaction and means you are corroding any aluminum part it and a liquid touch. But coolant has an anti-corrosive agent in it, that appears to protect the parts. In the heavy-duty diesels, you need to check coolant acidity as the anti-corrosive agent gets consumed, you then add what's called an SCA recharge, which recharges the additives in the coolant. In cars, I guess it isn't that big a deal, but it is important to note that coolant has a lifetime because of the deterioration and consumption of these additives.
Dex-cool which was designed for aluminum motors has a super aggressive anti-corrosive agent that works by removing oxygen from the coolant and thus preventing oxidation, the world of coolants is a pretty interesting place lol.

 

Yeah I feel dumb. Back when I started teaching (2016) at the trade school I still work at I started teaching 1st term electrical students. I taught "Essentials of Electricity". I used to go through this in class. But I haven't taught that class in like 3 years. It sucks getting old and forgetting stuff. Anyway yes the anode and the cathode will change based on what materials they are.

Another thing to this being that the water pump itself is a consumable part. The LS3 pump is press fit together. You can't rebuild it. So it's designed to be thrown away and replaced. I guess if it did corrode it wouldn't be the end of the world. So hopefully the cheapest coolant on the shelf at Walmart mixed 50/50 with tap water will ward off corrosion for at least a few years.

 

Curious on why you went with the LS3 water pump and spacers? I used a LS2 water pump on my LS swap, the water pump fits in nicely. I also used molded rubber heater hoses that has bend 90 deg's molded in, lots of clearance.

 

I wanted a water pump with the port for the upper radiator hose on the drivers side. That way I don't have to cross over the engine bay to connect it to my radiator. A Corvette LS2 water pump would be the same spacing as the LS3. And correct me if I'm wrong but the LS2 pump has the radiator hose on the passenger side. So I would have needed spacers anyway. Most any LS water pump is the same price on Rockauto. So why not go with one that fits the way you want. If I would have put on Corvette accessories in the first place I wouldn't have needed the spacers at all. But back when I first did the LS swap I couldn't find an aftermarket mount for the alternator in anything other than truck or F-body spacing. But the spacers gave me a steam port location without drilling and they didn't cost a lot.

Couple other reasons I forgot to mention. The LS3 pump has a sending unit port already on it. Also "supposedly" the LS3 pump moves more water. A fair number of people claim that they had lower temps going with the LS3 pump compared to other styles. I don't know if I believe this or not. But I guess it can't hurt.

 

Interesting, is it close enough to the rad that you can use the stock C4 upper hose?
If it is, I really like that solution.

 

I'm not sure. I don't have a stock C4 hose anymore. I won't know exactly how close it will be until the motors in. Once it's in, I plan on taking some measurements and then scouting out the junk yard to find something that looks right. I'll probably take the junkyard one and test fit. Then go and buy a new hose for whatever make/model I pulled it from.

Interesting fact, I did this same thing for the serpentine belt on the LS6. Turns out that with the accessory brackets I have now (no AC) I use a belt for a 2010 Nissan Rouge. It's nice to know that stuff being that when you go into any parts store nowadays all the kid behind the counter knows is "make, model, year?"

 

Just reading into your posts, your probably using truck accessories/truck harmonic balancer. I'm going to run a power adder on my car either a blower/turbo at some point, so I need the room up front. I'm using the corvette harmonic balancer. My kids 799 heads come out around 218 to 220 cc area. Not to bad for first timer.

 

I wish I would have run either truck or Corvette belt spacing. No, I'm using F-body spacing. Nowhere near as common as truck or Vette.

 

Ok so nothing new to add to the motor itself. I'm still debating on what oil pan I want to run. But I wanted to show what I've been doing to upgrade the fuel system to feed this thing. I haven't ordered a flex sensor yet but will soon. I found a cool .STL file on thingiverse.com that is a 3d printable flex sensor mount. Only issue is the factory sensors are only a 3/8 line. So I'm going to parallel fuel around the sensor with -6an hose. I guess this is how most people are doing it over on LS1tech so I'll give it a try.

Anyway I wanted to show what I came up with for the fuel sending unit and pump. I'm going to be using a Walbro 450 in tank pump with -8an feed and -6an return. The tank already has 2 5/16" vents with an anti roll over valve from the factory. This with a vented cap should give me enough air in. I figured I would use the old feed line on the sending unit as a return. It's 3/8" same as -6an. So I grabbed a stock sending unit out of an 86 Vette that I found in my local salvage yard. I had to lengthen the 3/8 line a little so it dumps the returned fuel right at the pump inlet. So I welded an extension to it. Then the old return line got welded shut on both ends. I wanted it to help hold the pump but didn't want it to be a way for fuel to pore out.

The next problem is the fuel level sending unit. The one in my 84 now barley works. According to my ohm meter the one from the 86 was worse. So I figured I would try something. It might not work but I wanted to give it a shot. So I removed the old rheostat and welded on a bracket. Then I pressed on a newer style (98-up) style rheostat. The ohms out of this are 40 to 250 I think. So then I bought a low cost converter. These are Ardunio based. Basically they turn your sending unit into a basic 5vdc voltage divider. The Arduino converts that signal into serial data (0-1024) and then converts that back into ohms with a digital potentiometer. So you can use any sender with any gauge you want. I don't know how well this will work. But it was only $30. If it doesn't work I can always use it to feed ohms signal to a temp gauge instead. Also if it doesn't work I'll just weld on a bracket that will hold a aftermarket 0-90 ohm rheostat. I had this one laying in a junk pile so I figured I would try it first.

So then I welded on some scrap pieces of 3/8 tubing and a piece of exhaust I had laying around to hold the new pump. I need to order a rubber sleeve for on the pump and then some hose clamps. I also ordered a PTFE flex line and a -8an to 10mm barb bulkhead fitting for the new feed line. 10mm (3/8) is what the Walbro pump has on its outlet.