Ok so here's the deal. My dad parted out his LS1 car, and still has his basically new tr6 plugs. My question is can I run these .035 plugs in my 5.3 which originally had .060 plugs in it? Kidn of a stretch I know but I think the truck is still on the original plugs at 120k and my budget is kinda tight.

 

I would assume that you could just re-gape them. I think the corect gape is 0.050~0.055 for the tr55's. If your on a budget and your on your original plugs then these would be a great replacement. Let some one else chim in to double check me.

 

im about to turbo my truck (01 1500hd) the plugs looked like crap, they were delco platinum ones. i put tr6ers in at about .035. runs fine, same as it did before. i figured it would idle a bit rougher but its the same.

 

They will be fine, but the NGK TR55's can be had for around 20-25$ so why not just spend the 20$ and replace them with the correct gapped plugs that are the right heat range

 

I would still re-gap them bigger since your NA. Just different heat range tr6=6=cold tr55=5=hot

http://www.ngk.com/charglossary.asp?kw=Heat+range

"The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage"