Valves to big??
Valves to big?? I have a set of PRC Texas-Speed 5.3 litter heads. My heads are stage 3, which have Manley Valves 2.08 / 1.60. The stage 2.5 heads come with the stainless Steel 2.04"/1.575" Valves.
Cam is Thunder Racing T-rex
Stock shortblock with arp rob bolts and all that stuff.
The PTV clearance is no good.
Are my valves to big for a 347 Ci engine?
My options are get new pistons with enough valve relief, or sell my heads and get a set of the stage 2.5.
Cam is Thunder Racing T-rex
Stock shortblock with arp rob bolts and all that stuff.
The PTV clearance is no good.
Are my valves to big for a 347 Ci engine?
My options are get new pistons with enough valve relief, or sell my heads and get a set of the stage 2.5.
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Even the 2.5s will not clear a T-Rex.
you need to flycut. and yes your 2.08 valves are counterproductive for a 346 (valve shrouding).
To clear T-Rex without flycuting you need 243 (LS2/LS6) casting unmilled stage 1 (stock valves) with stock gasket. Or LS1 casting.
Any stock castings with bigger than stock valves will need to flycut.
you need to flycut. and yes your 2.08 valves are counterproductive for a 346 (valve shrouding).
To clear T-Rex without flycuting you need 243 (LS2/LS6) casting unmilled stage 1 (stock valves) with stock gasket. Or LS1 casting.
Any stock castings with bigger than stock valves will need to flycut.
My machine shop told me that with the 2.08 / 1.60 valves Flycutting is not an option, they would have to take way to much off the pistons. Would the benefits or using a 2.5 be worth flycutting the pistons or should I just go with a stock size valve?
What will the difference in performance be between stock size valves and 2.04"/1.575" Valves?
What will the difference in performance be between stock size valves and 2.04"/1.575" Valves?
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
On stock cubes, if you can afford it, that would be nice. That involves a whole bottom rebuild, so getting a set of ported 243's stage1 for less than $1K is much cheaper.
On a stock shortblock with the t-rex cam what size valves will make the most power and be the best for my setup? If I don't buy pistons with valve relief what will benefit me the most even If I have to flycut the stock pistons? Sorry for the newbie questions guys I tried searching for my answer but came up short. Also how much can I take off the pistons (flycutting) with out having to worry about going to deep.
Thanks for any advice you can give me!!
Thanks for any advice you can give me!!
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Verdad Gallardo Ok I found out that my valves are actually 2.02/1.60.
My cam is 242/248 .610/.615 110+2
My machine shop told me that it needs to be cut .100 and they will not do it for me. There is a guy that I found local that can. My question now is will the pistons be to weak for nitrous?
My cam is 242/248 .610/.615 110+2
My machine shop told me that it needs to be cut .100 and they will not do it for me. There is a guy that I found local that can. My question now is will the pistons be to weak for nitrous?
Ok I found out that my valves are actually 2.02/1.60.
My cam is 242/248 .610/.615 110+2
My machine shop told me that it needs to be cut .100 and they will not do it for me. There is a guy that I found local that can. My question now is will the pistons be to weak for nitrous?
My cam is 242/248 .610/.615 110+2
My machine shop told me that it needs to be cut .100 and they will not do it for me. There is a guy that I found local that can. My question now is will the pistons be to weak for nitrous?
