88Fbody6L

iTrader: (5)

I have an LQ9 with 243 heads, stock MLS gaskets, LS7 lifters and MS3 camshaft. My question is this: with the stock pushrods I measure .050 lifter preload using the dial indicator method. I read somewhere that stock pushrods were 7.380 so I was banking on using 7.400 to get me to roughly .070 of preload. However, tonight I measured my stock rods and they are 7.400. Will this be enough preload or should I step up to 7.425 to get around .075?

JakeFusion

iTrader: (7)

Generally, with the smaller base circle of the cams ground on Comp billet cores, you need more pushrod to get the same preload. 7.425" is accepted as optimal for a stock engine with a Comp billet core cam.

outkast6991

iTrader: (34)

I'm running .035 on a similar setup with no noise at all

Ferocity02

iTrader: (60)

How did you measure the pushrods? There is actual length (end-to-end) which is easy to measure, and gauge length which is what Comp uses. Just something to keep in mind. I don't know if 7.380 is the actual or gauge length.

88Fbody6L

iTrader: (5)

I measured using theoretical length. Can anyone confirm that the 7.400 is in fact longer than the stock rods?

Ferocity02

iTrader: (60)

Theoretical length is the length of the pushrod without the hole drilled through it, I doubt you measured this. Drilling the hole through the pushrod puts a "flat surface" on the ends effectively shortening the pushrod slightly. If you measured end-to-end, then you measured actual length.

88Fbody6L

iTrader: (5)

Ok then. Actual length is what I measured

vettenuts

iTrader: (4)

I measured stock on a LS1, they were 7.385" gauge length. The 7.400" will be gauge length of bought from Comp or several other vendors, which all actually are made by Trend. I would contact Trend directly and get the pushrods. They also have very good technical support who I worked with when I did my double taper pushrods. I would also consider a stiffer 11/32" OD pushrod from Manton.

gagliano7

On my 2004 5.3 the 7.4's were longer than my stock pushrods.

88Fbody6L

iTrader: (5)

Thanks for the input, guys! I will go with the 7.4s then and that should give me .065-.070 preload.

A.R. Shale Targa

iTrader: (2)

If you haven't bolted the heads on yet....a 0.025 mill would help your preload
as well as add 1/2 point of compression...helpful if running NA

88Fbody6L

iTrader: (5)

Just thought I would update this......My stock pushrods measure 7.397 and my new 7.400 rods measure...well...7.400. So, all this gauge length, theoretical, actual stuff didnt mean a thing. Measure them tip to tip.