62radarlove

I've been cruising around the net as well as heavily surf on this site. In my reads i hear the 455 has oil issues when hitting revs above 5k. Does the 400 BBO have the same issue? I haven't seen or read anything as of yet about the 400's dying if you hold the rev above the 5k longer than the usual getting on the freeway run. I'm not looking for a high revving build but would like to know if i need to install a higher than normal pressure oil pump, to get her a bit more life for those fun feeling occasions. I know 400's aren't the **** but i do want to stay with it for my 69 442. Any suggestions on which one or direction is much appreciate. Thanks all.

2blu442

Yes, the 68-69 400 has a long stroke like the 455. Unless you build it I wouldn't plan to spend much time above the 5,000 rpm mark. But stock the torque and hp peaks were something like 3,600 rpm so there's no need to rev the engine beyond 5,000. The guys who race their cars can share more specifics on what you should do if you plan to use your car at the drag strip.
John

Run to Rund

The short stroke 400 has less trouble. All of them can be fixed for most of us without a lot of cost. Reasonable bearing clearances, rod side clearace, and a good oil pump make a lot of difference. The extra insurance of a bigger oil pan sump can help too. Modern, light weight pistons and pins reduce the load on the bearings. You can save 1/2 pound per piston assembly with modern design stuff vs. original, and that is a lot of weight that is being slung by the crank. With this stuff a late 400 or 455 can exceed 6000 rpm without blowing up, but if the camshaft doesn't let it make good power up there, don't go there.

455man

My understanding is the oil return is the bad part. There are tips you can do to help the oil return from the top of the motor to the oil pan quicker.

61reoldsman

Check out Dick Millers web site or mondello's they have oil restrictors that can be put into
the main bearings to keep the oil down in the bottom end ,they have restrictors too for the lifters galley too .i wouldn't do it unless you plan to rev the engine over 5500rpm

Run to Rund

The oil restrictors behind the mains are for the passages going to the cam. Today's cam bearings should already have holes at or smaller than .15" so restrictors are not used. The secret is not to help drainback but to meter the proper amount of oil through the lifters in the first place, like stock lifters did in the 1960s and 70s, before we went "global" and lifters came with Chevy oiling. The long stroke 455 and late 400 engines gave more trouble in part due to inertia vs. oil flow through the crank. Today you can get a bigger oil pump like the Melling 22HV that helps a lot--but it works best to have a bigger oil pan so it won't get sucked dry in any conditions. Put a nice chamfer on the oil holes in the crank, and a short "trough" at #3,6 rod holes to help oil get out onto those bearings; those crank pins have the oil coming out at the wrong angle.