Can anyone recommend a good aftermarket LS3 head that wont break the bank? Motor is currently out getting refreshed and I'd like to do a few things while its out. Currently running the TSP stage 1 N/A gen 4 cam. (225/236 .629"/615" 114 LSA, 109 ICL). We haven't torn down far enough to see if the Cam survived whatever decided to let go but may have to replace it as well. Curious to hear other alternatives that would work with a stock convertor (I'd like to continue to run a stock convertor just for drivability sake). Not trying to make a ton of power, just want a good streetable setup with good manners. The car does a lot of road trips and spirited backroad driving. Peak HP isn't a concern, but improved power/torque throughout the range wouldn't hurt. Anyone have any good recommendations?

 

With that smaller cam, you won’t pick up much even with good heads ($3500 range).
seriously consider doing a converter. My last car got a Yank ss3600 and drove almost like stock.

 

AFR LS3 Heads
Cam Motion LS 3 Titan 3 227/237 113+2
Ported/Rod- Mod OE Intake, Ported OE TB
2800-3200 Stall optional.... but strongly recommended.
Just my .02

 

How much of your children's inheritance do you want to spend? On the top side is a set of Tony Mammo's massaged aftermarket works of art. I think he's the best of the best when it comes to cylinder heads. On the bottom side is having your stock cylinder heads ported. That's the direction I went. Before spending big money on a set of cylinder heads, I'd add a TVS blower for a little more money and keep perfect manners and stock fuel eco. Way more power on the streets and no need for a higher stall converter either. I've done it both ways. Current Vette is heads and mild cam. Simpler and I can hook most of 2nd and all of 3rd without drag radials. Fighting to keep the thing going straight a 90mph isn't as fun as it used to be

Here's what I did. I think a similar set up would work well with an auto trans. First gear generates instant tire smoke punching it from idle speed in first gear. Even a stock stall converter would add to it vs my manual transmission. TxSpeed heads and mild cam build - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Probably the best flowing LS3-2 bore heads available, especially considering the mid-flow numbers, if only those valves were lighter; 122g intake valve, that's heavy compared to a stock 89g LS3 valve granted they're longer but still.

Great review:

 

My main reason for avoiding a stall is the cars ability to get on the power fast coming out of a turn, Every aftermarket convertor ive ever drove in a c5 or c6 has that same feeling where it takes a few seconds to flash. (and before anyone says it, yes I know I should have got a 6 speed but the price was right and trust me, id have rather had a manual). I'll def look into those heads. Considering the GPI SS1 Cam. Should have a little better idea of what needs replaced within the next few days.

 

You'll want to stick with a similar duration and LSA/ICL as what you have now in my opinion as those are two important specs that keep the power range in the areas you want it. I just finished a cam swap on my manual trans GS and desired for a similar power band as you (mine focused on HPDE/time trials). It's a slightly modified version of the Katech Torquer using Comp HLO lobes. Made 475whp and 474 wtq and feels so strong everywhere. Idle is good, no surging, would work great with the stock converter (I can still take off from a stop without using the throttle and releasing just the clutch).

It was making 400 tq at 2700 rpm and held 470+ from 4200 through 5300 rpm. HP peaked at 5200 and carried that flat through cutoff at 6400. I couldn't be more pleased with it, everything I wanted. Was not chasing dyno numbers, but instead something perfectly driveable and lots of mid range where I spend most of the time on track.

 

Nice! that sounds very close to what im looking for. Have a link to that Cam? Turns out my situation is a little worse than we anticipated. Lifter is seized in the bore, cam lobe was completely wiped, metal everywhere... haven't got to the bottom end yet but I dont expect it to be good. I think we're gonna be short block hunting very soon.

 

Is you opinion based on experience, just want to know, because I'm in a similar position looking for heads to go along with a small cam.

 

I'm of the opinion that heads do matter...even with a mild cam. Look no further than LS2 vs LS3. Similar cams. LS2 having more static C/R which I think offsets the small increase in cubes. 30 more horsepower. Tiny cam, better heads, nice bump in power. My little 0 overlap cam does really well with ported heads. I've had basically the same cam with stock heads. 35 hp less on an LS3. Some of that increase was due to a ported intake manifold and a slight increase in static C/R is also worth a little. With a well specced mild cam, you don't lose anything down low either. Mine will idle along smoothly in 6th gear at 38mph. Can also accelerate from a stop to that speed never touching the accelerator pedal. Just shifting through the gears. I'm not sure a stock LS3 will do that.

 

If you are drag racing it and have some drag radials, a converter can knock of .4-.5 while the heads might get .1-.2 with a small cam.

 

I have a manual. Still interested in whether you have persona experience with heads and small cams?

 

If you have a LS3 the intake ports are BIG. If you get the heads ported, obviously they get bigger. The ideal heads for a small cam would have smaller intake ports which would mean aftermarket heads, Trick Flow, etc. you would be talking $2500 and up.

 

I put aftermarket cathedral port heads on my LS3. I chose smaller ports than most people would have picked for this engine. They still flow better than stock LS3 heads, and the higher port velocity (coupled with the 11.8:1 compression given by the smaller chambers) make for a very snappy combination. My cam has only 1.5 degrees of overlap at .050" lift.

The heads are Mamo MMS220s. The cam was spec'd by Tony Mamo, and is 227/232 114+1 with just under .650" lift on 1.8 rockers.

 

Yes, LS3 ported intake and I was planning aftermarket 245/255 heads or a small 265 port job; I don't like 280 ports on an LS3 myself. But you're still not answering my question so I take it you have no personal experience combining a small cam with heads which is fine, just say so, everybody here including myself come to different conclusions by reading these forums; that's why we're here. Sometimes, though, when some info is of particular importance one wants to know if the other person has actual personal experience which adds more value to a statement. I don't want to buy heads if they're not going to get me at least 20hp.

 

Conventional wisdom and internet lore say just that. Can't argue with you there. That hasn't been my experience though. I don't believe my stock LS3 heads ported by Tx Speed are hogged out max effort examples. I also believe that a smaller cam enhances port velocity that conventional wisdom says you automatically lose with big port heads. Why would GM even consider square port heads on truck engines that need all the low end torque they can get? I know my LS3 will out torque any stock set up from idle on up. Again, conventional wisdom says it should be a dog down low with ported heads and any type of cam upgrade. My 1.875" long tubes with 3" pipes all the way back to the mufflers are also supposed to kill low end power compared to smaller tubes, collectors, and pipes. That hasn't been my experience either.

 

Yes, I have read your whole Miata build thread, very interesting; I think you made somewhere around 455/465 to the wheels all said and done? I'm sure that thing is snappy as hell but I was hoping to get me 500 wheel with good throttle response with heads & small -1 overlap cam. My plan was actually quite close to yours, getting church ports. Then I read a bunch old LS1 threads, with actual builders back when they were still more or less on there and realized that church ports need overlap to make power while still keeping decent throttle response as compared to rectangular ports which tend to lose throttle response with bigger cams and no extra compression. I think the smaller valve size has a lot to do with it too. Then I drove two cars, an LS2 church port C6 with a BTR 3 cam which has like 12.5* overlap and an LS3 C6 with spin's smaller 4* overlap cam which has a later intake valve closing point at 47*. The LS2 was down like 35 wheel but it still had good or better throttle response which made the car feel as fast if not faster than the LS3 and much more fun to me. It also drove as good or very close to the LS3 car, again I think the valve size curtain area and reversion has a lot to do with it, this was very surprising to me considering the 8* overlap difference. This is also when I realized that power is not everything and dyno driving is very different than actual driving and how important throttle response is to how a car feels, which was eye opening, as I didn't pay much attention to it before.

So the way I see it if you want to keep good throttle response with rectangle port heads but still get around 500 wheel you have to keep the cam overlap small with an earlier intake valve closing, keep the port volume small and raise compression. Just as an example I've seen 260 Mamo AFR rectangle port heads do like 535 wheel with 9* overlap, around 44* intake valve closing cam on 91 or same heads still do like 525 wheel with spin's 4* overlap cam. In both cases the heads were done and retested after the cam and were responsible for 35/40 wheel gains. The compression bump alone should be worth 10 to 15 wheel from doing heads.

 

Old motorhead's build thread is also a worthwhile read. Simple recipe, small 0* overlap 44* intake closing cam, ported TSP stock heads, wondering how much bigger tsp makes those ports, extra compression, underdrive balancer and exhaust; boom 500 wheel and according to Mr Old good throttle response too. I wish I could test that but I'm too far away.

 

You're sure welcome if you're ever in my neck of the woods. I may try to take some cell phone vids if I can figure out how to mount the cell phone to something that won't move around too much.

 

471 rwhp / 425 rwtq. I have data logs that show MAP dropping from ~100kPa to ~95kPa between midrange rpm and the top end. So I'm going to come up with a ram air intake. Pretty sure my intake path is a bit restrictive before the throttle body. That might get me a lot closer to 500 rwhp, but don't think I'd see it on a dyno. I'll be able to calculate the power changes from before / after data logs.

I get 31+ mpg on the highway ... that's one reason I opted for high compression and a mild cam.