I'm not sure the best place to post this, move if desired. David compares CD, port energy et al between OEM LS3 head and AFR as-cast LS3 Enforcer 238cc head. He claims AFR has a CNC version of this head as well, I presume he's referring to the older 260cc Mongoose and maybe he'll do the same for it in the future. Does David's historical knowledge easily transfer to LS long blocks? Are there new ideas from say Darren Morgan, Tony Mamo, etc. that supersedes David's knowledge?

 

I’d love to see a forged bottom end with these heads and a low lash solid roller. It would probably surprise us. Especially the mamofied versions.

 

He just released another video with some impressive gains after minimal port work.

 

I still HAVE NOT seen a AFTERMARKET LS3 worth the extra cash over stocks. Flow numbers are cool but we cant bench race those.

My cookbook thread showed multiple LS3 heads with different cams, intakes etc. They all run the same identical number at the drag strip. If i remember right one of the fastest LS3 headed cars in the thread had a some UNTOUCHED LS3 heads and a factory GM LS3 intake.

 

You're right. Everything I've seen about LS3 heads show it to be an excellent head for most mainstream applications, whether it be Richard Holdener dyno tests or flow tests.
It's a darn good head! And the LS3 intake is a great match for them. As I've said, adjust your preferred power level with a cam and/or a turbo or supercharger.

 

I don’t know about the LS3 line of Enforcer heads but the others for Ford & GM are the same Chinese heads that every other Chinese head vendor sells. Except the Enforcers have AFR valvetrain & hardware. If memory serves they’re the same casting as ProComp in some applications. I believe I read that one of the offerings in the Enforcer lineup is a Chinese stock 243 head knock off.

 

Typically, this is true. However, the LS3 Enforcer is an AFR design with 238cc intake ports and 2.080" intake valves.

 

I just looked at the ad and AFR says they flow up to twenty more CFM than OEM. So it’s more or less an OEM head copy with smaller valves I guess. I think I can sneeze more than twenty CFM.

 

It is a smaller valve, a 20cc smaller port, and a 12 degree valve angle. The interesting thing is that they put the head on a 416 stroker and had an issue with it falling on its face in the upper RPMs, but until that point, it was beating out the stock LS3 head.


This was before the port work, so I'm interested in seeing how it does with the minor cleanup. One thing to mention is that I had spoken with Mast about their small port LS3 heads for my 404, and they said that they have seen turbulence with their small port heads above 6500 RPM on 400+ cubic inch engines. So, I don't know if that is coming into play here. In the video, they are pointing at the camshaft's LSA, but I don't think an LSA is going to cause a plateau in the curve like they saw.

 

i actually wonder how much the stock LS3 improves with just a good multi-angle valve job and bowl blend. Those 2 things usually gain more than hogging the ports out.

 

Agreed! Also guys don't forget flow numbers aren't everything, got to look at velocity too!

 

Even still I think it’s a head that’s marketed for someone that is needing or wanting an OEM replacement for their LS3. I don’t think it’s really intended to be a “performance head.” How do you think they would’ve done bolted down to a stockish 376?

 

I've been thinking about doing this lately: valve job, bowl blend, and maybe some work on the exhaust ports.


I can't say as to how they would have done on a 376. If it truly is a turbulence issue, I would think that reducing the cubes would just move the turbulence further up the RPM range, possibly even moving it outside of the engine's usable powerband so it becomes a nonissue. Also, I went back to my emails with Mast, and they said the turbulence started at 6500, not 6000 like I said earlier.

To me, it seems like there is an issue with the valvetrain. Off the bat, the valve springs that come with those heads are rated to .600" lift, but the cam had something like .630" lift. Maybe I missed it, but I don't recall the video mentioning that they changed valve springs.

 

It would seem (keyword: seem) that they aimed for reducing port volume and valve size to gain velocity, then went with a 12° angle to gain back some unshrouded/unmasked flow.....

 

I'm looking at these heads for an ls3 shortblock I have. Engine has been under boost w LPE 317s for a few years . Im selling the car , but i want to hang on to the ls3 . I have a 64 c10 sitting on a 04 tahoe chassis w the full running gear from the tahoe . Gonna put the ls3 back to NA and put the l59 5.3 in the car w the current turbo setup to sell.
I had a cam ground years ago I ran NA in the ls3 that did pretty good as a mild street setup that ran really strong ( 11.60s, spinning to a 1.9 60ft, 119mph at 3500lbs, 3.42s, 2600 stall) that I'm going to put back in the ls3.
i.sold the stock heads years ago and need replacements. Looking around, i can barely buy a stock set of ls3 heads, rework them and do a good spring package for the price of the enforcers. The CCs are perfect at 70.2 ccs for my cam setup and pump gas ( Intake closing 59.5* ABDS , 8.72 dynamic ). The smaller ports should work well to make low speed tq for the 4000lbs truck.
I think the issue with rolling over w the 416 was too much velocity with the cubes. My 376 , I think, will make at.least as much power as stockers . The cam at 220-230 at .050 on a 108 +4 should make for a nice cruiser w enough power to.make it fun .
I will report back with results if I go this way . FYI, Weingartner tested the enforcers against a set of stockers with a nice valve job on a 408 w a mild cam and saw gains across the whole curve. Only 5 to 10hp, but if the trend is solid, I think the smaller 376 would see even better gains .Stockers had a 1 cc smaller CC too for what that's worth. Heads seem to be tailor made for street 6.0-6.2 builds that live below 7k rpm