i still cant justify another 1k unless theres a reason. an extra 10hp when youre making 650-700 just isnt enough for my build. quality? thats a reason to spend 1k.

 

The more I read the more I think I'm gonna get WCCH to do a Stage 3 CNC on my LS3 heads.

 

actually its an 800 dollar difference, prc is 2399, mast is 1599 each, so 2400 vs 3200

 

1599 each bare vs 2400 assembled.

 

well not quite bare. they told me those were complete but that i would want to upgrade to hollow stem intakes, titanium retainers and a different spring set. that made the masts 3800+ (vs the 3200) with the same parts as the prc's for 2699. plus prc usually runs sales which can save another couple hundred bucks.

Head: LS7 12° 4.125" - 4.200" Large Bore CNC ( $1399.99 ) 510-206 (2) $2799.98
Intake Valves: 2.200" 5/16 Hollow Steel Race Valve (5.450") ( $23.99 ) 442-200 (8) $191.92
Exhaust Valves: 1.600" 5/16 Solid Steel Race Valve (5.450") ( $15.99 ) 421-600 (8) $127.92
Rockers: Large Bore Rocker Stand for GM LS3/L92 Rockers ( $39.99 ) 491-005 (2) $79.98
Springs: Dual .650 Lift Springs ( $375.00 ) 906-101 (1) $375.00
Retainers: Ti Dual Spring Retainer ( $11.99 ) 931-101 (16) $191.84
Locators: Steel Dual Spring Locator ( $47.99 ) 930-101 (1) $47.99
Locks: Machined Steel 7 Degree ( $35.99 ) 932-701 (1) $35.99
Total $3,850.62

 

Nice looking work on the subframe.

If you want the better quality the Mast cylinder head is really nicely done. There is a lot to cylinder heads and much of it is going to be that which is expressly understood by the only builder/machinist/port engineer... and those like him/her. There are so many principles involved beyond flow numbers that when people start throwing flow numbers around I really begin to question their opinions. Horsepower is a product of how much air is drawn into the chamber- yes, but it is also a product of the shape of the port entry, the path of the air and stability of the air as it travels through the throat, enters the bowl and finally approaches the valve. Then there is the valve placement in the bore (centerline), valve job, the shape of the chamber, the location of the spark plug, etc... Consider that while the air has to be there, it has to be "high quality" air or, in other words, highly efficient in how it flows. We have to remember that the combustion process is also a part of how well a cylinder head works and this involves how the air/fuel is burned. Also throw in the fact that the designer of the cylinder head has years of education, data, research and new development all the time. I would be willing to bet the physical weight of a Mast LS7 head is actually substantially more than the TSP which indicates to me the casting is thicker or perhaps cast from a denser alloy. I believe the Mast has a thicker deck as well. Another excellent choice for an LS7 style head in an aftermarket heavy duty casting would be Allpro.

The GM LS3 is junk and other than being fit for a factory application, I wouldn't put them on any engine of mine. I would option for a large, well designed cathedral port or an LS7...or better such as a C5R, the new CT/DR or Mozez or LS-R. The aftermarket LS3 such as Mast builds has greatly improved valve centerlines which makes them a more refined and much more potent cylinder head.

But, after all this good to say about Mast, I have only dealt with ETP and Cary (Performance Inductions) prior to the merger with Mast. I tried to call Mast yesterday, three seperate times and no one answered. I guess every company has their shortcomings but if I can't get someone on the phone to make a purchase, I may look elsewhere. I didn't call to leave a message, I called to talk with someone and get some information.

 

^^^ Call Shawn at Virginia Speed. He might be able to help you out....

Mast was a little challenging to deal with for my heads. He may have something around the shop you need...

 

I am surprised you would recommend a cathedral port head?
What brand and size intake runners would you use for a boosted 427 lSX block ?
Would the TFS 245 be big enough?
I do like the mast ls3 heads and they would give me more supercharger manifold options than the ls7 heads for sure. I guess the cathedral port would give me plenty of options as well.
For me there is $1000 difference in price between the mast and trick flow heads however I do wonder what the performance difference would be between the two and would the mast be worth the extra dollars. Both brands are supposed to be excellent quality.

cheers
Jason

 

The TFS is a very good head and would be excellent for boost. If you go with an aftermarket LS3 port, Cary's heads are the cats meow. But, I say if you are going to go LS3 you might as well go LS7- better port entry and line of sight to the valve meaning more potential overall. BUT, there are some very fast cathedral ports out there! There is a thread on here right now of a guy running a TFS head in the 8.90s with a 3050ish race weight stock suspension 4th gen and a hydraulic cam! Greg Good has done some very fast cathedral ports too which I believe were based on an ETP casting which is Cary's stuff or Mast now. Check this link:

https://ls1tech.com/forums/drag-raci...aulic-cam.html

 

Good to know and not a far drive from me either.

 

Thanks for that link and your input; that link certainly opened my eyes up and I guess that with the TFS 245 and a bit more cam there would be a few more ponies to be had N/A.

With boost I assume this combo would make huge power and probably be more drivable on the street or in my case off road.

Would I be correct in thinking that cylinder head port design and choice is less critical in a boosted application?

I also wonder if the cathedral port or rectangular port would have the upper hand with boost added.


If this 427 tfs 245 engine combo in the link; used the Mast ls3 heads how much extra power do you think it would have? My guess would be probably no more than about 20hp and a similar gain in torque.

I have all but ruled out the LS7 heads because with a P/D blower I have far more choices with the ls3 or cathedral heads. If I was looking at a turbo or a centrifugal blower set up; I would certainly use the LS7 heads, my choice of heads has now been narrowed down to the tfs 245 or the mast ls3 and I need to weigh up the H/P vs $ value and the cathedral vs square port flexibility of manifold choices and roller rocker options.

What heads do you run on your LSX 438 that is listed in your signature?

Cheers
Jason

 

I would say less critical unless you are going for an absolute max effort deal that is scraping every last 1hp from the combination.

I doubt the LS3 from Mast would improve this particular engine at all- as a matter of fact, they may not perform up to par with what it being run now. I can gaurantee those TFS heads have been heavily re-worked by someone specifically for that application and the guy that did them is absolutely top notch. At that weight and running those times, that engine is making about 850hp which would tell me those heads are working to their fullest potential. That car is seriously very impressive and most certainly took a lot of hard to work to get there.

Performance Induction (Mast) LXR-275 which is a cathedral port. I had the Super Victor manifold from my previous engine which I got before any of the LS3 or LS7 stuff hit the streets. It was also a Christmas present from my dear mother so it has some sentimental value (as goofy as that may sound). I know the cathedral ports can be fast, so I stayed with it. They are Cary's latest and best effort cathedral head. I ordered those direct from him prior to his merger with Mast and I absolutely trust his word. Excellent guy to work with too; very personable and accomodating. I just fired it a couple weeks ago and I can tell you it feels very strong on the street but I should have some track data this Friday. Fwiw, my old engine was 404cid, ETP-225 heads, 239/243 cam, 850 carb, pump gas and the car at a 3200 race weight, 3.89 gear, drag radial, full exhaust, footbrake ran a best of 10.110 @ 133.49.

Always thinking towards the future....If I ever change heads on the LSX it will be to a C5R style port like Cary's (Mast) PXR. I hope to work with him on that project too. My current heads/intake will most likely be transferred to an engine going in my C-10 build. But honestly, that thread on the 8 sec hyd roller 4th gen really makes me want to work harder to make my current stuff as good as it can be.

 

I find it interesting that the op in the 8sec thread claims that he has out of the box standard TFS 245 and is making 650-670hp.

Maybe he is trying to make these heads sound a lot more standard than they really are.

 

I just bought a set of PRC's and cam from Texas Speed. Next month I will be putting everything I bought from them on my GTO.
When I received the heads, I opened up the boxes and all I can say is WOW! very nice work. They machined the heads to match what cam I decided to go with so I know that it will work.
I can't say anything bad about TSP, because they never tried to sell me anything more than I needed. I really appreciated that.

 

I was recently told that TFS are making an LS3 head and they are still working on some final port work but should be ready soon.


Does anyone know anything more about these heads?

 

There is a fair amount of B.S. in some of those comments I think. I would say you have to really look at what is possible from those parts and it is doubtful out of the box heads and a .625 lift cam are going to get it done.

Fwiw, I ran my car Friday (this is a cathedral port motor) to a best of 9.85 at 138.43 for the day. Again, I am not sure what your goals are, but at my weight that mph translates to somewhere betweem 730-745hp. I use the mph because my 60-foot and 1/8th mile times are way off from the mph and 1/4 mile ET. Once I get the car to leave better it should run into the 9.60's. I am still a hydraulic roller and pump gas.

Best of luck to you.

 

why is the all pro head ls7 not in the mix ??

 

The PRC casting absolutely 100% the material they say it is and is made in the USA. I would say the PRC and Mast make real close to the same power.