60fthnter

Well i may have deal worked out where i can trade my 4bolt TFS 245s with a nitrous exhaust port for a set of out the box PRC 6bolt heads. This would be the cheapest way for me to get a 6bolt head without selling mt TFS 245s and re-buying new heads.

The planned setup is 416 (LS3 or LSXblock, depending on heads at the moment)
Twin tc 76s (journal bearing)
Cam is 24x/25x .632 .632 117 + x
FIC2000s
4L80E with t-brak and circle d converter
1000 plus rwhp is the goal

The cam was ground with running the TFS 245s in mind but I dk if going to the PRCs would compromise the cam or not?

I would like to hear some ppls thoughts...

I8UR4RD

iTrader: (16)

The LS3 block is not a 6 bolt design. You would need an RHS, ERL, or LSX block to make the PRC's 6 bolt design worth having. If you plan on doing that you can always trade later. Those TFS heads are going to make great power as well, and if the cam was ground based on the flow specs of the 245's then I would keep it and enjoy that benefit for the time being. I am not quite sure how much cylinder wall your going to have left with the ls3 @ 416CI either. Seems a little thin for the amount of power youll be able to push. You really need a nice *** shortblock to utilize that setup.

BOBS99SS

iTrader: (2)

Some good info posted above,

TermnEatr

iTrader: (24)

Im guessing he knows about the ls3 not being 6 bolt thats why his block choice has not been made per his original post. My advice get the lsx and 6 bolt heads when pushing a decent amount of boost I know tons of people have made it to your goal with 4 bolts but its better to over build anything.

I8UR4RD

iTrader: (16)

yeah but the fact of the matter is, that the ls3 is in his list of choices for a block, and if he picks that block, then this thread is pointless because 6 bolt heads will have no benefit to him anyway. based on his post count....he may not have known. I agree though, he should not even consider it if he plans on using them for real. I have 6 bolts, and I plan on putting them on a 427 ERL in a few years

Z06_Fan

Maybe the 6 bolt vs non-6 bolt question you asked is actually over-simplifying what you're trying to do.

1000+ is 1300 FWHP with that transmission, that's alot of power!!

High power aluminum LS guys swear by the LS2 over the LS3 for cylinder wall thickness and higher % of core shift reported in LS3.

To get to 416ci (assuming 4" stroke) you want engine longevity? Think BDC piston skirt support from your high HP build........LS3 was not made (LS2 either) for that much stroke. I know lots run it fine but do you want an engineered engine or parts put together?

How about your main bearings? Don't you think pinned mains and even perhaps billet mains would help stabilize the bottom end for reliability and consistancy?

Back to the head........you want essentially 20+ psi of boost with .630 lift, did you consider intake valve weights and sizes for bore size limits and valvetrain stability between the two heads you mentioned? What are the lobe profiles of the cam? How often do you want to change valve springs ?

Anyways, consider these items, weight them as you feel the need and ask your engine builders or others if they think all of this is relevant to your goals !

Good luck and have fun with it !

James@ShorTuning

Keep the TFS245's... they are a much better head IMO. If you want to push them and keep from lifting a head get a good tuner! 1000hp isn't hard from a forced induction stroker with that nice of a cylinder head. You can also have your block setup for 1/2" head studs. The 5th and 6th bolt don't add a huge amount of clamping force to the deck and 1/2" head studs will be plenty for a measly 1000rwhp.

eb02z06

iTrader: (18)

Listen to James here-the TFS 245's in 4 bolt will go way beyond a 1000 horse.

Going to the other heads is like going backwards.

Brian Tooley Racing

iTrader: (13)

I have a customer who ran a LS2 block with some TFS 235's that I did with the lightweight LS3 valves. He ran 8.30 @ 166 with LS9 head gaskets at 20 lbs of boost and never pushed an ounce of water, on E85 pump gas.

LilJohn

Keep the 245's...

That cam suuuuure looks familiar... lol

Zo6 fan... as far as the cam the lobes are HUC lobes.

Its a very stable lobe with heavy valvetrain including aftermarket rockers.

In all reality with that cam... a 416 inch motor aught to make damn near 600 on nuts if you put any compression in it at all. You should be able to make that power on 16-19 psi easy.

Keep the heads.. put 1/2 inch studs in like James said and let it eat.... I designed that cam with that heads capability in mind... If you change heads... I cant say how that cam would work with the PRC heads.. the trickflow is a better head in my opinion.

And stop worrying about it idling too smoothly... lol

60fthnter

Bought a LSX block, and TFS 245 6bolt heads from BTR! I think I am all set boys!

I8UR4RD

iTrader: (16)

[QUOTE=James@ShorTuning;17048477]Keep the TFS245's... they are a much better head IMO.

Just wondering why that would be......to my knowledge there is very little info on PRC's upper end heads, and texas speed usually puts out a really nice product. god knows the have the machines to do so with. They even cost about the same I believe.



I think you are in for a nice motor here real soon! be sure to start a build thread.