Well I will apologize early for the question with many possible factors...

Currently running an iron 408, prc stage 2.5 ls6 heads, Mamo pro 10mm Yella Terras, 242/254-629/609-114lsa, (around 11.5 cr, can't find my deck height number to be exact), fast 92/92, 1-7/8 headers,th400, 3600 stall, 9" w/ 4.11s.

- had some valve float around 6500 rpm and after talking with Mr. Mamo, decided it was due to heavy *** valves in my too small for a 408 heads lol. So limiter was set at 6250 since power was dropping off by then. Rest of the valve train is great with high rpm link bars and stage 5 Manton pushrods. Only made 450/430 to the wheels.

So after realizing my mistakes and the car still way too slow for me, I plan on going forced induction and shooting for 1000rwhp in the next few years. After a lot of reading, I may turn this motor from a 408 down to a 370 since a read a lot about the piston being pulled from the bore too much and piston rock, etc. I also know that the car will be mini tubbed, upgrade the th400, and upgrade the 9".


Now this is where my question begins. I am wondering if I can pick out a head that will work for both NA, and being boosted, while working on my current 408, and work on my future possible 370. I warned you that this would get stupid lol.

I was looking at trick flow 235, 245, or their 255 ls3 heads. If I stay cathedral, I would keep running the 92/92 till I went boosted. With my size cam, I am not sure if I can go back to stock rockers ( I know that the normal rule seems to be under .600-.630 lift should be fine) or should drill the heads to 10mm to run the yella terra Pro's. I want to pass the 500 rwhp NA mark, correct my valvetrain mistake, and still be able to use these on the future motor

Any insight into my madness?

Appreciate any help. Thank you

-Mark jr.

 

Sounds like your at a fork in the road. As I'm sure your aware it's all about the right combo for making the best horsepower and with NA that typically means milled heads with smaller combustion chamber for higher compression ratio. With boost your kinda headed in the opposite direction. With that being said if you are serious about running boost I'd buy set of good NA heads for now to get the hp your targeting and then sell them later and recoup some money and get a set of budget boosted heads later. From everything I've looked into the heads aren't as big of a player on a boosted application. Going from NA to boosted you are easily gaining more than enough hp to up the grin factor even on a set of budget heads. I'm sure you understand all this already just giving my thoughts on what I'd do in your situation and if I was on a budget.

 

MMS 235 with NFI (nitrous/forced induction) exhaust port.
Or MAMOFIED TFS LS3, Talk with Tony.
235s would work equally well NA or boosted, and have a better
Valve size for 4.060" Bore, and better for a 370" Engine IMHO.
Then put dished pistons to drop comp for boost later.

 

I would opt for the TFS 245cc cathedral port heads. Guys are making big numbers with those heads, and the thicker head decks are a very good thing for boosted applications.

 

I see both sides of the deal. I read a lot of people saying to use TFS 235's, and a lot saying that you can just run stock 317's and just cram the air through.

What I would like to do is not buy heads for now, and then sell them for a different set. I'm already going to have to do that with my th400 and 9" center / axles in the future.

One thing that I am not sure of is milling the heads or just leaving them alone. They are 70cc, I currently have factory cnc ls6 heads that were 64 cc, but had .002 milled off to clean them up. Not sure what they equal now.

I always figured that I could get these milled a bit, and then make up for it with dished pistons and possibly a thicker head gasket.

If I went with cathedral port heads, I would keep the 92/92 setup. I know it is not the best but I would only be giving up 10-15 hp and not worth going to a 102/102 when I would need an aluminum intake for forced induction.

I am just collecting opinions and info to make a decision, I have TEA local to me, I will also send a message to Mr. Mamo and get his opinion on the subject to.

Thank you for your replies, a lot to think about.

-Mark jr.

 

Mark,

My MMS 235 NFI head is perfect for you....I can drill and tap for the 10mm Yella Terra Pro rockers on the CNC machine (the best way to have that done).....they make big power N/A even though I actually designed them with nitrous and forced induction in mind with their larger higher flowing exhaust port and larger exhaust valve. This head flows 270 CFM on the exhaust....its one of the highest flowing exhaust ports on an LS head I have ever tested....it will work well N/A but really pay you dividends when you add boost down the road.

You know how to get hold of me for more information....that's the head to run on this combo without a doubt



-Tony