I have LS swapped my 98 C2500. It came from a 2001 Chevy Silverado with 117k miles. I threw in a sloppy stage 2 and it has a horrendous lifter tick. I completely rebuilt this motor at home and tried to do my youtube and LS thread research. I plan on putting in a truck norris cam and LS7 lifters. I installed a standalone Aces Jackpot kit. It runs fine except for the loud tick. It also has 25 psi at warm idle which I am concerned about (it might be cam bearing clearance (Durabond CH10)) replaced oil pump with M295. I already have an upgraded trunnion kit and .660 beehive springs. I am wondering what length pushrods I need. Block and heads (862) are stock.

 

If only one is ticking it isn't pushrods. Likely a bad lifter.
If all are ticking it likely IS pushrods.
Call the cam grinder and find out if it is ground on a reduced base circle.
If it is, you need longer pushrods.
It is best to measure for them, but you can get close by adding the reduction in base circle RADIUS, not diameter, to the stock length.

 

I'm going to replace the lifters with LS7 lifters as several are ticking. A few of my rockers are loose side to side but none up and down. I let some oil out to check it after letting it idle for 30 minutes and there were metal shavings, I'm assuming from rolling a lobe, which is why I am going to replace it with the Truck Norris. I want to buy everything and get it installed asap but if I have to buy the cam and lifters then measure and then buy pushrods, I will. I am just wondering how to proceed.

 

IF you get a new cam, find out if it's on a reduced base circle. Then get pushrods accordingly. Measuring would be best, however.

 

Best way is to just buy a PR checker, and check preload. What are they, like $30? OP stated he rebuilt the engine, but what lifters did he use for the rebuild??? They shouldn't be bad already, unless they're pure Chinesium, made down to a price and not up to a quality....

 

Nearly every aftermarket cam has a reduced base circle to create the added lift. The lobes cannot stick out further than the cam journals then How would you get it into the block? More lifter preload than necessary is absolutely always better than not enough preload.

If nothing's been shaved, milled or cut, you cannot go wrong with a 7.450 in pushrod. I don't even bother to measure or check the preload anymore. When I'm putting together stock stuff there's no point the tolerances are just too good. .600" lift cams and under and I just order the 7.450 without thinking no matter what it works

There's some pretty good tests out there on push rod length in LS applications, many experiments with preload, especially between the intake and exhaust valves (different length rods) and the effect on the power curve.

The minimum amount of preload will give you the best torque and is the least reliable, The maximum amount of preload gives the best peak horsepower and is the most reliable

Sounds like a no-brainer to me man

 

I agree... If it's stock heads, gaskets, and lifters, 7.450 work almost every time. If you mill heads, valve job, thinner gaskets, after market lifters, then you are likely going to need to run shorter push rods and measure for correct preload. Digital 8" caliper and a adjustable pushrod makes it simple. Measure twice cut once. There is a weeks worth of reading material while on the ****'r covering how to do this properly.

 

buy the $30 pushrod length checker and measure lol

 

OP here, I never had it on the road and maybe a few hours at idle, rarely breaking 2500 rpms. I finally got around to taking it apart. The cam looks fine, cam bearings had normal wear, lifters had some scoring around the outside but nothing extreme- they were all in the right position relative to the trays, pushrods had no wear on the lifter side but had some on the rocker side- which was expected, rockers had no wear. If it isn't the cam bearing tolerance causing low pressure, I'm at a complete loss. Any advice or insight is welcome

 

Pinched pickup o'ring.

 

It looked completely fine when I took it out, when I put it together it seemed to fit snug