[acammer]

Originally Posted by dwizzlehart

I've got a 2013 2SS LS3, currently torn down, about to be cammed. Has forged pistons in the bottom end (Guy that put them in says they have .040" on the top deck.), trunion rockers, and BTR Dual valve springs (.660" lift, standard size guides at .505".) Also has COMP 5/16" 7.400" length pushrods. Also have Ferrea Intake Valves.

Essentially I'm trying to put the largest possible N/A cam in the car without creating any PTV.

Texas Speed has their new Stage 4 F-35 Cam at 235/248 and .649"/.615" with a 111 LSA.

My question to you all is this cam too big? Do I risk binding a valve spring? Can I just get shorter pushrods? If so, what length do you recommend?

P.S. All of these valve train upgrades and forged pistons are already done because I had a guy put a stage 4 BTR cam kit in for me, he did it cheap(get what you pay for), but too cheap. Didn't torque down cam bolts and they backed out whilst driving down the highway....sad face. Wouldn't cover rebuild cost either. So that's why I'm here.

I have a GPI SS3 in mine with a full stock bottom end, heads have never been off the car. BTR .660 lift platinum springs. No PTV clearance issues, no coil bind issues. The SS3 has a fairly similar profile to the F-35. (wonder what TSP was looking at when they put that together....) Both are considered max effort with a stock bottom end with regards to PTV clearance - lots of guys running both without issues.

But these guys are right - you're not stock any more and you really want to do some actual PTV measuring to make sure you're in a safe spot. Also, I dunno about the F-35, but the the SS3 is cut on a smaller base circle and requires a longer 7.425" pushrod for proper lifter preload. You should be measuring for that (proper lifter preload) as well.

The F-35 and SS3 are both really good choices for a stout NA build. I recommend you give GPI a call and talk through your combo, they may be able to offer some insight on your options. It sounds like with the aftermarket pistons you may have plenty of relief and could reasonably running a more aggressive cam that usually requires fly-cutting in stock applications. Not sure what your goals are, but that's something to consider - Ryan at GPI could help you spec out something custom that would really maximize your setup.