I had a lengthy talk with Richard @ WCCH yesterday as I am having him do me a set of his stage 3 big valve 821 heads for a project.. We discussed the BTR heads and he told me he received a sample head from BTR with their CNC port on one cyl and the rest as cast for him to flow and experiment with. He mentioned his flow bench came right in at what BTR quotes for flow 360cfm at I think . 650 lift. Weigartner received same head and his bench flowed like a touch over 370cfm, so you can see that benches do vary. The CFM is just a single aspect of getting the air into the cylinder. The valve placement is going to make that head work The smaller valve and higher COD should add up to crazy torque numbers.

 

Does the larger bore increase or decrease flow?

 

increase for certain

 

Eric Weingartner had actually stopped by the Yella Terra booth at PRI in 2025 and complimented me on the design of the LS3 head that I handled for AFR back in 2014 which was one of the last projects I worked on with them prior to launching Mamo Motorsports.

It was a brief conversation but it was nice to meet him in person and I appreciated his feedback. I actually had some of my Mamo Motorsports cylinder heads on display there as well at the time

Seeing these numbers on the SAME bench is the key to really being able to draw some conclusions. Both heads are excellent.....the COD is actually extremely close when looking at both heads.

The AFR has only a 3.8% larger valve area advantage (2.165 vs 2.125) and some of the flow numbers are larger than that percentage (8% more flow @ .300....5.5% @ .400 etc. etc.) which nets a slightly higher COD figure at those lift points. Bottom line they are both very close in terms of efficiency which is what the COD is essentially telling you

Has anyone poured a runner in this new head yet? That would be another interesting metric to look at....looking at the photos the runner doesn't look that large so Im not expecting a big difference there either. The MCSA on both would be another metric of importance

Keep in mind guys I also offer my Mamo Motorsports version of the AFR casting which I call my MMS 26X head.....launched that in 2017 ish.....I use the same AFR castings to build my heads. They have slightly larger 2.170 hollow stem valves to reduce mass and some additional tweaks for even more flow (about 5 - 10 CFM more than the out of the box AFR piece which is already impressive).

All three of these heads will outperform a ported GM factory casting in a huge way.....superior valve angles, geometry and much better efficiency (higher airspeed)....there is simply no comparison.

This new BTR head certainly has alot of potential....but its not the 2nd coming of Christ which the Internet has made it out to be. I think with further development it could exceed the better 12' inline heads by a small margin but as others have mentioned the largest gains from the LT platform this design was essentially taken from come from the fact LT engines are direct injection and no fuel in the ports makes alot more room for more air to get to the cylinders.....that's the big advantage LT engines have. But the valves get dirty and that hurts flow and performance long term.

Enter the brand new LS6 engine being launched in the 2027 model year.....its designed with direct and port injection which is probably the best situation to have. Valves stay clean and my guess is the direct port is likely providing the bulk of the fuel requirements....technology has really been driving this industry the last 20 years.

Without a doubt we are living in the best days of this hobby.....hopefully future government regulations don't muck it up!!

-Tony

 

It's a shame GPI isn't on this blog. At the moment, they could probably offer the most relevant comparison the BTR head as they do their own small bore LS7 head and offered the canted Edelbrock before. Of anyone, they could legitimately say it's better/average/worse etc. It's wouldn't be the end all opinion, but it would be loaded with insight. I'm just dying to see if it's really better than LS7 architecture. My gut says no, but we will see.

 

I guess it's better to hear it first hand, but Brian said in one of the podcasts posted in here that GPI was going to use these heads instead of their small bore rectangle heads i think it was. This mentioned in a post in here too.

Here it is. Post 55

https://ls1tech.com/forums/generation-iv-internal-engine/1973283-canted-valve-heads-3.html?utm_source=share-link&utm_medium=button&utm_campaign=share&utm_cont ent=post

 

If your building an engine with displacement the LS7 is still the King of the hill in my book assuming its a properly designed efficient port that isn't overly large.

The valve placement in the LS7 platform is superior offering more room around an even larger intake valve.

Comparing my 12 deg LS3 26X head (which flows 385 - 390 CFM with a 260 cc port)....even my mid priced Stg 2 LS7 head with a 2.205 intake valve valve flows 408 CFM and the port volume is only modestly larger (265 cc vs 260).

Its extremely efficient and moves a ton of air at a high rate of speed but its best suited for 4.125 bores or larger although its still works well on an LS3 sized 4.065 bore also......still hits about 400 CFM on that size bore.

A canted valve LS7 head certainly sounds intriguing though.....LOL

If I wasn't so busy running my business I would love to design something like that!

All these heads we are discussing here are represent the cream of the crop so to speak where they will ALL outperform any type of OEM ported heads due to their solid CFM numbers, high airspeed.....high efficiency.

Your already compromised starting with an OEM port as you have to ADD material in all the right places to make it a more efficient piece and that's just not feasible or cost effective

-Tony

 

I'm agreeing 100% on this, but it's curious to see how far they can push the other architecture. I also agree on the canted LS7, that could be the ringer. Then again, how much more of a jump is it to just go with a true clean sheet canted head like the Edelbrock or Dart 10 degree? It's nice to have options, that's for sure. Tony, quick question for you that you may know. I had heard AFR is possibly transitioning to all china production on their heads. I'm hoping it's Internet BS, but you are probably one of the few who know for sure. That being said, I think it's in their interest to keep the premium USA line, even if they don't make as much.

One other side note for you, do you have any plans for a Mamo CID LS7 head? I'm going to be in the market for some for my AMX project, probably a stock rocker base casting. Richard at WCCH has his version coming soon. I know you are king of airspeed, I would be looking for a very aggressive, violent type airspeed in what I have in mind on a NA 427 iron block.

 

I bought a set of the BTR LS3 canted valve heads and opted for LT4 Ti intake valves. They are at Gromm Racing in San Jose, CA to get the CnC port program and assembly. Hopefully get them in late June 2026.
I want to put them on a turbo alum 5.3 setup for road racing. I probably need them like a hole in my head but I like shiny things. hahaha

 

Looking forward to the results.

 

You read that wrong, it's 366.5cfm at .65 lift on Eric's Sanez bench, not over 370. So, yes benches do differ but if BTR said around 360 (you think) and WCCH confirmed seems to me, in this case, they're pretty close Dave. If the Superflow reads even higher, maybe that's why Eric prefers the Saenz. Thanks for the WCCH info, I was wondering if they were going to develop a BTR canted version of their own.

 

Did Gromm already develop their port program for the BTR heads, last I heard they were starting to work on it? Any chance they're going to provide some flow numbers to You? If so, please post them here.

 

Here is tough question Tony. What if you're not looking for the "king" head? You want to make descent power or the most you can make but your main priority is longevity and reliability? Which head would you go with than? I'm not taking about just head longevity either, but the whole valvetrain package. I have been seeing more and more lifter failures as everyone is pushing boundaries, even Johnson and other premium brands have been failing often. What if you want a lighter valve, you want to keep lift reasonable, so spring pressures stay low like say with a PSI ML1511 beehive, and you want metal guides because those are going to last longer, maybe much longer than any bronze; especially with stock rockers which you have to use because they're also light and will keep spring pressure as low as they can be?
What head would you go with than and how would set it up?

I think a more people are interested in that head for their street driven whatever if they actually want to use the car and depend on it anytime for say a long road trip?

 

wow are those titanium valves worth it? I see they are the same size as the $15 hollow stem LT1 valves. But they cost $125 a piece and are 85 grams instead of 93?

 

I have seen a picture of a titanium LT1 valve on a scale showing 71.6 Grams without the lash cap so add whatever those are, I guess. They wouldn't' make much sense at 85G, that's for sure. My question would be: have they proven any more reliable or stronger in the LT1 platform with cams and higher spring pressures as compared to the hollow stem valves? I have heard of what seem like more failures of the Gen V LT1 hollow stems compared to LS hollow stems, but maybe I'm wrong about that and it's just my perception.

 

I saw that exact facebook post of the guy weighing the valve and it showed 71g and someone else pointed out the lash cap and that is like 4 grams.

I thought that steel was actually better for durability than titanium. At least with retainers, I heard that the steel is better for long term and that is why stock applications use it, whereas titanium was lighter but more brittle over time?

 

Did you not believe the picture?

 

I worked in tech support early in my career for a few years. You learn not to trust what users tell you or that they are doing something correctly, or that they have tried things that they said they did.

When all AI and google results say 85 grams or 79-84 grams, I don't necessarily believe that the scale was calibrated correctly. However, I found another person weighing one and it also says 71 grams, so I guess they are.

But my larger point was that I don't think titanium is more durable. It might be stiffer but that doesn't mean it will last longer i don't think. However, if the last caps are 4 grams and these wind up being 75 grams vs 93, that is a significant loss and would definitely help with power. Brian Tooley also said that heavier valves pound the valvetrain, and the weakest link is lifters. So lighter valves are easier to control and keep from slamming.

 

Interesting, I get it, and you're right LS7 valve weights are out there and known so Ai has those figured out but not so for the LT1 valve weights yet. Whose tech support did you work for?

 

I think my LS7 titanium valve (they are aftermarket 2.20 size) are like 78 or 80 grams with a steel tip insert.