Heads Too Big ?
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,771
Likes: 0
From: MANDEVILLE, LA La
Heads Too Big ?
I have a chance to buy a pair of Trick Flow Gen. X LT1 Heads that have been ported.. The Numbers.For my 95' 350 LT1.
Int= 319 @ 600" / 28 Hg
Ex'= 227 @ 600" / 28Hg, 2.02/1.60, 64 cc.,sp= CC 155/400 to 630" Lift.
Cam I'm using will be a CC XFI268 HR13.I don't want too big of Heads for Drivability Reasons (Daily Driver).The price is Very attractive.Brand New, never run.
Thanx
Int= 319 @ 600" / 28 Hg
Ex'= 227 @ 600" / 28Hg, 2.02/1.60, 64 cc.,sp= CC 155/400 to 630" Lift.
Cam I'm using will be a CC XFI268 HR13.I don't want too big of Heads for Drivability Reasons (Daily Driver).The price is Very attractive.Brand New, never run.
Thanx
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Did they start off as 195cc?
Who ported them/sheet?
What do they measure at now (cc on intake port)
What are the other flow #s, .600 doesnt tell that much.
Leaning towards "yes" (too big) on your question but need more info.
Sounds like youre aware that there is such a thing as too much.
Found that out recently on my own motor...had someone do them many yrs ago. Great job but they measured out to 230cc
Who ported them/sheet?
What do they measure at now (cc on intake port)
What are the other flow #s, .600 doesnt tell that much.
Leaning towards "yes" (too big) on your question but need more info.
Sounds like youre aware that there is such a thing as too much.
Found that out recently on my own motor...had someone do them many yrs ago. Great job but they measured out to 230cc
Drifting
Joined: Dec 2005
Posts: 1,313
Likes: 2
From: High Ridge Missouri
If they flow 319 @ .600 on the intake that's pretty dam impressive just how big has the intake runner been opened up to?!?!?
If they flow that well there is a chance the port is too large for a 350 (kills port velocity) but if your building a 350 to turn 7500rpm they might be just fine.
Then again I might be talking out my a$$, much more knowledgable people on here than me.
If they flow that well there is a chance the port is too large for a 350 (kills port velocity) but if your building a 350 to turn 7500rpm they might be just fine.
Then again I might be talking out my a$$, much more knowledgable people on here than me.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
I've got a couple of problems with what they are trying to sell you.
Number one.
319CFM with only a 2.02 Intake valve?? I know a thing or two about head porting and that kind of number out of a low port head with such a small bowl isn't normal. They can't be made big enough with the small valve. Those heads barley break 250CFM OTB... they can be ported to flow over 300CFM but with a 2.08 valve, a crap load of epoxy and a 230+cc intake runner. Call me skeptical on the posted flow numbers.
Number two.
64cc combustion chamber. Your going to take a huge hit on the compression ratio. Yes you can cut them down to 54cc but your going to close up piston to valve clearance and hurt the flow numbers (whatever they really might be) pretty badly because you place the top cut on the backside of the valve job so close to the flat deck surface.
A stock set isn't even an upgrade from the GM LT4 heads....
Will
Number one.
319CFM with only a 2.02 Intake valve?? I know a thing or two about head porting and that kind of number out of a low port head with such a small bowl isn't normal. They can't be made big enough with the small valve. Those heads barley break 250CFM OTB... they can be ported to flow over 300CFM but with a 2.08 valve, a crap load of epoxy and a 230+cc intake runner. Call me skeptical on the posted flow numbers.
Number two.
64cc combustion chamber. Your going to take a huge hit on the compression ratio. Yes you can cut them down to 54cc but your going to close up piston to valve clearance and hurt the flow numbers (whatever they really might be) pretty badly because you place the top cut on the backside of the valve job so close to the flat deck surface.
A stock set isn't even an upgrade from the GM LT4 heads....
Will
Last edited by rklessdriver; May 19, 2011 at 11:18 PM.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Maybe they flowed it on a 4.125 bore 
and fluffed/folded
Good to see the OP is asking before buying.
Ill go out on a limb and claim the #s are bs and that head is over 230cc easy. Closer to 240+
and fluffed/folded
Good to see the OP is asking before buying.
Ill go out on a limb and claim the #s are bs and that head is over 230cc easy. Closer to 240+
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Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
If they're really cheap slap them on yourself for fun and tell us how the manners are ! Or just resell them! I agree the 319 out of a 2.02 sounds incredible. Everyone is questioning port volume etc... I call straight up BS on whoever flowed them. Either that or whoever is selling them added a little masala to the numbers to help sell them faster. As we all know adding bs to any story goes hand in hand in the performance world lol.
Safety Car
Joined: Sep 2001
Posts: 4,153
Likes: 553
From: Glenbeulah Wi
I doubt they will be too big to work well in your application. If you could get all of the flow numbers you could check the low lift flow and high lift flow. The flow numbers appear to be impressive and it may make great overall power. More information is needed to see if they will work in your application.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
I wouldn't install a set of TFS if you gave them to me. Only use I have for TFS is as a boat anchor. I learned the lesson the hard way and it cost me an expensive block.
If you must use them, I would have the heads stripped bare to the aluminum and replace EVERYTHING with new stuff that wasn't from TFS
If you must use them, I would have the heads stripped bare to the aluminum and replace EVERYTHING with new stuff that wasn't from TFS
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,771
Likes: 0
From: MANDEVILLE, LA La
