Re: Rebuilding sbc400 ... looking for some parts advic
Yes, the heli-coils are a good idea. They are stronger then when the block was new. For the street head studs and main studs are a waste of money, use it for something more helpful. If you do go with main studs the mains should be align honed with the studs.
The hyper pistons run a tighter clearance then forged so are quieter and seal better. They can withstand alot of pressure, but will shatter fast if rattled. So detonation and nitrous should be avoided with these pistons. Unless you plan on running nitrous, high rpm, or somekind of forced induction, I would say your choices should be cast or the hyper pistons. You will make better power due to the better sealing from the tighter fit.
I too say stay away from the total seal piston ring scam. The top ring is forced out by cylinder pressure to make the seal. The problem with total seal rings is the second ring is the gapless ring while the top ring remains stock style. So the cylinder pressure goes past the first ring's gap, but is then trapped by the gapless ring. The pressure equalizes between the two rings with the cylinder pressure. This causes the top ring to lose it's seal. So basically you are running on one compression ring. The second problem this creates is heat removal from the piston. Most of the heat is removed from the piston through the rings. Once the top ring loses it's seal it no longer transfers heat. And it is the ring closest to the heat of combustion.
Since this was once a drag engine, I would be interested in a couple of things like intake port CC's,and valve spring pressures.