Rod,main and head bolts

**JMac** · 06-11-2008, 06:23 PM

I'm doing a build on a ls1 and trying to make it a little more dependable with being able to put down some good hp #'s but what I was wondering is how good the stock main and rod bolts are on the ls1 and do I really need to go with ARP bolts on these two places?

How good are the stock pistons?

And last Question can I run a really bid cam with stock pistons and alittle bit bigger valve?

**BlwnCamaro** · 06-11-2008, 06:34 PM

yes definately go with arp rod bolts, main studs and head studs. It will strengthen the stock rotating assembly and head clamping force considerably cause the bolts are like the first weak point. I'd run a little extra clearance than stock on your rod and main bearings with a melling high volume oil pump. These few little tricks will help alot on durability. With the bigger valves and a big cam you would maybe have to flycut pistons just in case and then check clearance very carefully. With stock sized valves some common "big" cams like ms4 with .640 lift clear stock pistons with no fly cutting. Good luck
Jesse

**JMac** · 06-11-2008, 07:00 PM

Originally Posted by BlwnCamaro

yes definately go with arp rod bolts, main studs and head studs. It will strengthen the stock rotating assembly and head clamping force considerably cause the bolts are like the first weak point. I'd run a little extra clearance than stock on your rod and main bearings with a melling high volume oil pump. These few little tricks will help alot on durability. With the bigger valves and a big cam you would maybe have to flycut pistons just in case and then check clearance very carefully. With stock sized valves some common "big" cams like ms4 with .640 lift clear stock pistons with no fly cutting. Good luck
Jesse

I had planed on going with the thunder racing T-Rex cam. Do I still need to flycut the pistons?

**BlwnCamaro** · 06-11-2008, 07:21 PM

Originally Posted by JMac

I had planed on going with the thunder racing T-Rex cam. Do I still need to flycut the pistons?

That is a pretty big cam, you may want to consult with the guys at thunder as they have alot of testing and experience with that cam on different combos. Talk to Jeff or one of his techs. I can however tell you that most of the larger cams on the market are designed to have max lift available with stock valves and pistons in mind so with the bigger valves you will definately more than likely have to flycut stock pistons with the TREX. But Jeff and them should have a pretty good idea. Also its always better to err on the safe side and each custom combo is unique so I would double check clearance on your valvetrain by the mocking up with clay technique. Even if you flycut in advance it is better to have extra clearance and peace of mind!
What size valves are you planning on running?
Jesse

**BlwnCamaro** · 06-11-2008, 07:28 PM

If you dont want to worry about that dont put bigger valves, just as long as your head gasket thickness is the same and your heads have not been milled down you can run trex and clear without a problem. However I still like to check my clearance when I have engine down to be more thorough and have peace of mind even if it is supposed to clear theoretically. However I do many cam only upgrades with engine in car for my fbody customers and always use the cams from tsp and have never had a clearance issue on stock setup with big cams like ms3 or ms4. There is a lot of R&D behind these cams and I trust that if TSP says they will clear stock setup that it will, and they have never let me down.

But if you have your heart set on bigger valves fly cutting is not that hard or expensive, but some suggest it weakens a stock piston a little but most aftermarket pistons already have valve reliefs built in to piston when it was made. The theory of removing metal from original casting is what some would suggest weakens but I dont think anyone has proven one way or the other. I dont think it will be a problem as many use flycutting technique on stock pistons with good results and most piston failures result in ringland area first anyways. If you can afford some forged pistons just go for that and dont have to cut or worry and they will be strong. Will set you back about 600. Good luck
Jesse

**JMac** · 06-12-2008, 01:10 PM

Originally Posted by BlwnCamaro

That is a pretty big cam, you may want to consult with the guys at thunder as they have alot of testing and experience with that cam on different combos. Talk to Jeff or one of his techs. I can however tell you that most of the larger cams on the market are designed to have max lift available with stock valves and pistons in mind so with the bigger valves you will definately more than likely have to flycut stock pistons with the TREX. But Jeff and them should have a pretty good idea. Also its always better to err on the safe side and each custom combo is unique so I would double check clearance on your valvetrain by the mocking up with clay technique. Even if you flycut in advance it is better to have extra clearance and peace of mind!
What size valves are you planning on running?
Jesse

I've already got manley 2.02 intake and 1.575 exhaust (it's was just the next size up on both).

**BlwnCamaro** · 06-14-2008, 01:18 AM

Originally Posted by JMac

I've already got manley 2.02 intake and 1.575 exhaust (it's was just the next size up on both).

I would flycut and then double check clearance with these slightly larger valves and the TREX. Or if you can afford go with aftermarket forged pistons with built in valve reliefs. Jeff and those guys have probably run 2.02's with the TREX and could give you a good idea, but better safe than sorry. I seen them doing some flycutting on pistons when i was at thunder racing but not sure what cam and combo it was on. Good Luck on your rebuild.
Jesse

**JMac** · 06-14-2008, 06:40 AM

Originally Posted by BlwnCamaro

I would flycut and then double check clearance with these slightly larger valves and the TREX. Or if you can afford go with aftermarket forged pistons with built in valve reliefs. Jeff and those guys have probably run 2.02's with the TREX and could give you a good idea, but better safe than sorry. I seen them doing some flycutting on pistons when i was at thunder racing but not sure what cam and combo it was on. Good Luck on your rebuild.
Jesse

I've decided to go with forged pistons so I can get the valve reliefs and not have to worry about it as much. Thanks for all your help and advice.