Dave F

before fly-cutting is needed?

calongo_SS

iTrader: (7)

Depends if heads are milled, and valve sizes. The biggest cam available that I know of that will clear pistons w/stock heads w/o flycutting is the T-Rex from Thunder Racing. (242/248 .618/.602 110 lsa)

xfactor_pitbulls

iTrader: (16)

I actually thought the tolerance on the intake side was so close that you need to flycut regardless. I talked to TSP yesterday about the MS3 and the clearance on it is only .050 on the intake side. The T-Rex is a bigger cam, realistically its nice to have some margin in there. More than .025 or whatever it would be. To me .050 is a bare minimum. Crunch the math, I wouldnt run that cam without flycutting.

Brandon

goober35

iTrader: (1)

I talk to TSP a long time ago. It is not common but can happend if GM TQ you heads down to much tha the MS3 cam will be even closer than u think. You will have to check it. Trever told me that. You are going to need a dile indicator on a magent and some test springs. I would check it if i where u.

dazman

you could have a bigger cam then the trex in a car , its just all about valve events. the "duration" and "lift" numbers dont mean near as much as the numbers that they dont show you thats why the comp 236 will NOT fit in a car without flycutting but the tr 242 will

the trex should be fine without cutting but just dont ever miss a shift. lol

mike

xfactor_pitbulls

iTrader: (16)

I appreciate the info Goober. However I am putting on LS6 Heads shaved .030 off. So I am going to flycut anyways.

Brandon

Blown 98 Z

iTrader: (2)

I run 236/ 240 601/608 114 +4 Comp Cams XER

goober35

iTrader: (1)

That cool man. I did not know that you where having the heads milled.

PREDATOR-Z

I wouldn't run a .050 PVC even if you promised to rebuild for free. Anything less than .100 is suicide on the street, especially on M6.

zamboxl

iTrader: (1)

just about everyone out there runs a cam and there some pretty giant cams out there. I got a tr224/224 and i got no problems, thast not a big cam but if it was as close as they say i wouln't even be able to run it.

DAPSUPRSLO

iTrader: (14)

Just to give you an idea I run a 239/246 106lsa 106icl .651"/.613" Comp LSK/Comp XE-R cam on 5.3 litre heads cut .030" with 2.02"/1.60" valve and .090" valve reliefs I cut in my pistons. Clearence is right around the .060" or so range. I checked them with a checking spring to though. Remember, if you check with a checking spring you will get almost no valve train deflection which you will get with normal springs (thanks for the info Jason). I.E. if it clears with checking springs on the valves then it deffinately will clear with normal valve springs.

xfactor_pitbulls

iTrader: (16)

Yeah well, hence I am going to flycut a full .090 off.

Brandon

xxboomer408xx

will a 237/242, .603"/.609", 113 LSA cam on comp X-ER lobes clear?

NO5.0

iTrader: (1)

Question? Give me an idea of how you will notch the pistons? With the motor in the car still? Im wondering because this issue is keeping me from running the head/cam combo I want to. Thanks

DAPSUPRSLO

iTrader: (14)

You use the valve relief cutting tools from Isky on a head that has the same deck surface as the head you plan to use (i.e. a head cut .030" needs a head that has been cut .030" to locate the fly cuts in the piston properly).

The only thing is you either need to have the valve seats removed from the head or have the carbide cutter machined to fit to make the cuts. If you do not do so the cuter will not fit in between the piston and the valve seat when you bolt the head down.