Hello All, For my own satisfaction is there anyone that knows how big you can bore and stroke a 425 nailhead? Would the cylinders have to have liners installed? Is there a place on the web with info. I ask this because I have an extra engine laying around and it might make for a good winter project. Hank
Nailhead Stroker A MT 4.010 stroker crank in a .030 over 425 would yield 475 CI. These cranks are not made anymore, but are available from time to time. You would still need rods to fit and a good set of forged pistons. That is how I would do it. Otherwise, the cost would be prohibitive. There was a 401 stroker built to 470 CI on the GSCA site using a custom King crank at $2800, SB Chevy rods at $1200 and custom pistons at least $800. Throw in a good set of rings and you would have at least $5000 in the bottom end. That is without assembling anything or clearing material for the stroke. Now you will need heads, valvetrain and custom headers that will keep up with the airflow demands of the increased CI. A 475 will need to move at least 10% more air to maintain the same rpm as a 425. This is difficult and will be expensive with such small valves and little room for larger valves in the OEM heads. The 364/401/425 heads can flow with a good street/strip Stage-One head, but that is with all the tricks, and it will not be cheap. There is always forced induction, and it may be cheaper then stroking all around. Good Luck Cheryl
Re: Nailhead Stroker Hmmm, fabbing up a homemade super- or turbocharger set-up might make an interesting winter project, and you have all summer to scrounge around the junkyards for parts.
Brien, see my avatar picture at the left? That is exactly what I have, a supercharged 401. It isn;t running right now, unfortunately, as I bought it that way from a friend. Look in the nailhead forum for my intro post, and you can see a bigger picture of it.
Yeah I saw that. It's pretty sweet man. In fact, that's probably what got me thinking to make that post. Be sure to let us know how it runs when you get it going. It might encourage other people to do similar things with their nailheads.
