Strictly NA for the time being. The more I read the less enthused I become with positive displacement. It seems to just be a tire fryer or a heat soaked SOB.

That's getting WAY ahead of myself though. I just like staying NA... "Possibly" a bit of Nitrous Outlet down the line.

 

If staying n/a, get as high CR as you can. Is this pump gas? The spray will like it in the future as well.

 

Heads are standard at 63cc. I need to get on a calculator and see where I'll be. I know I'll be using a Cometic .040

It will be nothing but quality (Shell or Chevron/Texaco) 93 octane.

 

040 Cometics
slugs out .008"
64cc = 11.07
63cc = 11.24
62cc = 11.39
With those larger than stock valves you sure don't want to have to flycut unless like you alluded to Ed going 218-222 range on the intake lobe to get it to fit
I'm seeing the gears spinning inside your dome.....might wanna add some cubic inches to the air pump underneath those KILLER heads...

 

Yeah... I was just playing on Wallace racing calculators myself. I'm fairly certain I'll need a 4.030 head gasket. I've gotta call Mast, AGAIN.

They're 63cc factory. The 2.08 valve doesn't really bother me. I'll fly cut the **** out of the Pistons if need be.

As for the 218-222 intake lobe, that's more due to how well they flow. They really don't "need" more than that. I'm thinking 230's exhaust myself, but who knows what kind of wrench my headers throw in the equation.

I've heard tri-y's love overlap, and I've also heard it doesn't make a difference.

I've only got about 3 things to figure out to get this build solid in my head. (Yes, you heard the gears GRINDING)

I'm pretty set on the T&D rocker arms, so that's settled.

Solid or Hydraulic - dictates what lifters, cam, who's doing/grinding what...

What head gasket diameter?

How much, if any, should I mill...

If I plan to reuse these for a 402 I DONT to skim too much off. That in itself pretty much tells me for the time being im going to have to live with 63cc chambers and focus more on quench.

 

If you look at your factory manifolds, they are a try-y design which works well with the factory wide lobe separation camshaft.
I always thought try-Ys were less dependant on overlap as the scavenging pulses happen much closer to the port than a four into one. The exhaust gasses are much hotter and traveling way faster in addition to the proper cylinders being paired for maximum pull. So the pull on the intake tract during overlap is more aggressive and less dependant on the number of degrees the valves are both open.
Back in 87 I was the first to run Doug Thorley Try-Ys in my neck of the woods and they always worked really well with 114 LS cams...albeit Gen I stuff but I ran those headers on at least a dozen different 355,383,406 combos and they just work !!!!

 

Moved back to GenIII.

 

Spoke with Kip today about Mast med bore LS3 heads. What springs does Mast use in their heads? Specifically their Roller setup. If people are still waiting on their heads, they shouldn't be much longer. They said they have 20 heads going out. They have a 2 week lead time on the heads right now.

 

Also Doc, I see you've decided on t&d rr. I've been leaning that way as well if I go the solid route. Kip is running the Jesels in his corvette, but I've seen a ton of great reviews on the t&d's on yellowbullet. What swayed you?

 

One of the best threads going on tech at the moment.

 

Their solid roller setups I'm not sure. Dave or Chris would be the ones to talk to, but I'm betting it's a PAC 1207x or 1208x...?

It was actually a few threads there is the Jesels breaking, as crazy as that even sounds. I haven't been able to find a single thread yet of a T&D breaking, and from what I've heard T&Ds customer service is better.

Lol, it's going to be a while before its together. ***** expensive, so it's getting done in stages. I've got on the shelf so far:

ARP head studs
ATI 10% balancer
Mast heads

Also a full Prothane kit for a C5 and Goodridge Phantom stainless brake lines.

Gaskets and all are a cake walk, so no biggie there.

Timing set will be Hinson C7R with whatever billet gears I can get by themselves
Manton 3/8" PR's
T&D rockers (hopefully I can use stock valve covers)

I'm sure there's stuff I'm forgetting, but that's the plan so far.

 

Yeah, I was really surprised at some of the Jesel threads I've seen. I wouldn't have believed it without all of the pics. The t&d's do look promising.

 

The Mast heads should have at least .165-.170" valve drop on the intake and surely close to .200" on the exhaust.

That's at least .020-.025" more than a cathedral port 15* head.

Depending on the margin thickness on the intake and exhaust valve, the heads that Dr. Whigham has may even have .170"+ valve drop on the intake and .200"+ on the exhaust.

TFS 12* LS3 heads are .178" intake and .240" exhaust!

Basically you have a lot more P to V to play with on these type cylinder heads. With the improved low lift flow from the steeper valve angle and larger valve diameter, the Mast small bore heads don't need as much overlap to promote efficient gas exchange during the overlap event. A 15* head with smaller valves needs more valve overlap for a given cylinder volume as it does not flow as well during the overlap event. Remember, the engine doesn't know how many degrees of overlap the cam is ground with. It just knows area, pressure and flow volume.

Shorter overlap events don't need as much P to V clearance either which is another benefit when utilizing a stock bottom end. Combine this with the steeper valve angle allowing for more valve drop distance, and you can easily obtain 11.2-11.4:1 SCR with a decent size camshaft all while achieving very safe P to V clearance.

 

Hyd Roller stuff uses 1221X SR stuff 1324s and 1325 usually.

 

Thanks for he replies gents. I was unsure on the springs Matt, and Martin that's good info you posted.

To me, 11.2 - 11.4 seems a bit low (for my taste). I ran 11.7 on the AFR 205 combo I had (chambers @ 59cc)

Where would I "want" to be? They're standard at 63cc. Should I just leave them alone and run a Cometic .040?

Suggestions welcome. I'd like to reuse these down the road though on a 402... Well down the road.

 

Hi Doc,
I have available Manton Series 3 and Series 5 between 8.225 and 8.155, some with less than 10 minutes dyno testing...


Christian

 

Thanks
This is the same issue I'm having. I'd like to run 11.5-12.1, but I hate the idea of milling a brand new 3k+ heads. I'll probably just run a .040 Cometic and try to get the compression around 11.0.

I'm still undecided on switching to a solid roller. I have to pull lifters anyway because of a slight noise that I've seemed to pinpoint to the lifters. It was making this noise with the stock cam and the stock cam(4k-ish miles) looked fine, so I'm thinking with 1k miles on the new cam, there's going to be no issues there either. So I'm stuck between mast heads with my current cam (232/238 .621/.603 113LSA) and running some johnson link bars, or swapping to some T&D rockers and getting a new solid cam specced. This is a stock bottom end LS3. I think the low lash solid is more of a want. Isn't it all really though?

 

Kip can do you a hell of a job, I know that. His Vette is quiet as hell...

 

Christian I'll keep that in mind when I go to measuring when I'm putting her together.

Just off the top of your head what have you noticed difference wise between the 3 and 5 series?

 

Dave,


The Intake titanium valve weight on my ETP are 88 grams.
The exhaust valve are 66 grams.
There was no noticeable difference between the 3 and 5 Manton Series revving to 7400 rpm


The Intake valve on your set-up might be around 123 grams as per the ones that came originally from Cary and Ed Curtis on my ETP...and the exhaust might be 92 grams.


That is some extra weight to consider in the possible pushrod behavior.
Manton Series 5 vs. 3 for your application is an item I would debate with Ed or with the boys at Manton.


Christian