Hey guys me and my buddies have a 408 ready to be assembled. Going to put the rotating assembly in tomorrow. Just wondering what y'all recommend gapping the rings to. Well be around 18 psi to start for tuning and end up at 24 pounds. CR Will be 9.79:1. Wiseco -15cc pistons, 64cc p&p 243s, 4.060 .040 HG..I believe my calculations are right. We're thinking .24 top and .26 bottom. Will not see spray. Twin 65mm turbos. Thanks for any insight and knowledge..this is our first time building an engine but I think we're on the right track

 

Thats what I have mine at in my 370. What rings are you using?

 

They're rings that came with the wiseco pistons

 

Bump for more answers..plan on assembling when I'm more comfortable with our ring gap choice. Anyone else?

 

I'd probably open them up a bit more than that but not much.

 

What do u suggest

 

In the same boat here. My rings work out to basically 25 thou for the top and 15 thou for the second ring based on the ring manufacturers recommendation for a boosted engine. This is from the formula provided and my bore size. So... with a turboed 370 that will realistically see up to 20 lbs boost should I open the second ring up? I am running diamond forged pistons in it.

 

hi I was just wondering about your post description running the -15cc pistons.im fixing to purchase some myself and read a 10.2 cr ratio on a 65cc head.i know the 243's are 64 but not much different I was planning on running 243's p@p as well on my lq4 6.0 .30 bored 408 but with -20cc wiseco's. just wondering what difference there is and what did you do to come up with 9.79:1 on -15cc pistons. Im assuming its the 4.060 .040hg but I don't know what that refers to 100%. thanks

 

A machine shop told me .004 gap for every inch of bore on N/A and .006 for every bore inch turbo.