PTV Clearance Torquer V.3/ PRC 243's
 

i know people ask these kind of questions everyday and i have searched and tried reading and decided maybe someone could give me some light. Im getting ready to finish my car just waiting on the heads and was wondering if i should have to worry about PTV clearance with the V.3 and PRC stg 1 ls6 heads. The heads are unmilled, and the block is brand new.. i couldnt find anyone with a similar setup that was close so i decided id ask.. thanks to anyone who can help

I don't think it will hit, but it will likely be close... You don't want to over-rev, float a valve, blah blah blah... Your best bet is to check for PTV before you finish, make sure you get GOOD springs/retainers/etc, good lifters, correct length hardened pushrods, etc.

i have prc duals, and the heads assembled by texas speed.. i might just sell the cam and go with a 233/239

Yes you should be worried, so you need to check it to make sure.
:nod:

From similar setups I've seen .06x to .07x PTVC on intake.
Measure you'll be in that range.

that is way to close for my liking.. i like peace of mind and want the setup to last.

You could always flycut the pistons or run a bit of a thicker gasket as well... But pushing the limits to make a little more power isn't worth losing the extra peace of mind in my opinion :nod:

WTF????? that is a bigger cam. FWIW lots run the MS4 and stage 1 heads no prob so....... Yes it is tighter than I would personally run but many on here get away with it it.....

well this is the third motor going in the car, and id rather not have to grenade another one for something that could have been prevented.. the first( stock motor bustend the ringland on 7, the second motor had issued with the heads andended up trashing everything and this time id rather just be somewhat safe. and the 233/239 doesnt have the .643 lift the v3 does

lift has nothing to do with piston to valve clearance. stick with what you have it will clear fine if you stick with stock gm mls headgaskets.

The only way you'll find true PTV is simply by measuring it. Every motor is different. You cannot relly take any one opinion Vs the other.
TV3 is a good cam, but a bit harsh on intake lobe.
Is your motor a stock shortblock or forged? What do you want to achieve with your motor? Good power and longevity? run a bit softer lobe with similar durations. Like a 228/234 .588/.598 110+1 LSA, 11* overlap so still pretty strong lope, 6500>6600 shifts, good midrange trq. TSP does custom grinds.
It is all in your decision and the reality of the use of your motor.
There is also 230/230 .612 /.592 111+2 LSA, .08x PTV clearance on intake, very strong midrange trq, 6500>6600 shifts, softer XFI lobe on intake but still benefit from extra lift. very good "all around" street strip cam. 8* overlap good thumpthump.

Are you willing to pay for his engine if it has PTV issues??

Exactly, people can only guess. Once you start the engine and it eats itself alive, you are the only one that is paying the bill to rebuild.

exactly i want somehing thati can be safe with.. because in reality i might miss a shift/gear and i dont want another $3k mistake. people may call me crazy but for the little power i might lose, ill make it up somewhere else

.050 lifts have little to do with PTV clearance since that occurs near BDC and contact will occur from 10* BTDC to 10* ATDC.
Poeple confuse .050 lift with tappet lift on a regular basis.

If you miss a shift, even with stock cam, you will pay the price. At least bent p-rods.
As I said earlier, think and be truthful to the reality of what you want this motor to do. Choose your cam based on that.

:werd: Its been mentioned here so many times but I dont think it will ever really sink in that max lift really doenst play too much in ptvc since a piston crash will occur at the lowest lift area.

well thats my misunderstanding, im still learning.. but i just think its to agressive for the dd that i put prob 50 miles a day on and drive all night friday and saturday. but if i go to the v2 will it be as abusive on the valvesprings as the v3?

v2 is less abusive.

if its less abusive, and im sure the power wont be to far off

The point is that if you putting in a fresh short block WHY would you not have the machine shop notch the pistons, sounds nuts to me.

call me crazy or nuts, i would just have something a little less harsh, changing the valvesprings all the time would get old/expensive