Guys,

I am finishing up a 3800 GTP build and do not have adjustable rockers. The issue is that I have installed an aftermarket cam (smaller base circle than stock) and I am now using the Comp OE-R 875 lifters that require a different preload than stock.

What I am being told is that to get the correct preload I will have to get the correct length pushrods since I will not be able to dial in the preload using the rockers (b/c they are non adj). So now I am trying to figure out how to translate 0 - 1/2 turn preload into pushrod length. Any ideas? I am getting ready to buy a pushrod length checker but how do I know when I am at the correct length?

THanks!

 

From my experience, you will likely need an adjustable rocker to get the correct preload on those lifters! They are very particular on preload!

 

Thats funny. When I spoke to ZZ performance they told me they dont sell adj. rockers to support the lifters they sell. Instead they recommend getting different length pushrods. Is it even possible to use the pushrod option? Is that common to do to get the preload you need? I've never heard of that before.

 

They might not offer them, but that doesn't mean they're not needed. It's pretty well documented that it requires an adjustable rocker for the OE-R lifters. You might be able to hit the exact preload via pushrod length on them one out of 50 tries (that might be giving them more credit than it deserves actually). Other lifters, such as the GM LS7's, Comp OE's, etc have a wider range of acceptable preload though, and you can easily hit your preload by changing pushrod length with them!

 

Ok cool. I am going to send these bitches back and go with the OE's. Thanks Matt!

 

Anytime! Let us know if we can help! We can get basically any length pushrod you need in .025" increments at competitive pricing, even for the V6 cars

 

Ok cool, I will let you know once I get my pushrod length checker in the mail. Can you confirm that the LS1 lifters are the same at the L67 pushrods? 1999 Pont GTP.

Thanks!

 

LS1 lifters are the same as V6 lifters, yes. They also use the same diameter pushrod (in general), but your pushrods will be down there closer to 7.200" rather than the usual 7.400" or so on the LS1's

BTW: If you know anybody who wants a 2000 GTP Daytona car, I have one available for relatively cheap!

 

thank you Matt for all the great work.