I know it has been answered before but what is the best clearance for a 408 strocker by lunati with a procharger at 14-16 psi , Lunati told me that the perfect clearance would be .0038 on the main and others people are telling me that 0.0025 should be enough.

 

I'd go with .0025" - .0027" on the mains with the iron block - slightly tighter if this is a street only motor. You will have no oil pressure if you put the engine together with .0038" on the mains. Check the rod bearing clearance too. Make sure that isn't excessive as well. Around .002" to .0025 with good quality steel rods. Run on the low side for street.

Lunati grinds their cranks to minimum published journal sizes. You will most likely need .001" under bearings or a std. and .001" under bearing combination to come up with correct clearances for your application.

Steve

 

On my 370 my mains are at .0021-.0023 and the rods are the same. My car is my DD so i want good oil presure and i want it to last a lot longer. The looser the clearances the more power it will make but the motor will not last as long. .0038 would be a perfect clearance if this was a pure race car.

Just for ***** and giggles what are your ring gaps. I did mine at 20 on the top and 24 on the bottom.

 

Thank you for answering my question Steve , I had King's bearing with my stroker kit and I wondering if they are making .001 bearing for those engine ? I'm going to call them , I don't know if Clevite have that ? I thought about aligned bore the main but right now they are round perfect and I don't want to loose that

Francois.