After reading for hours upon hours on this forum I have decided to do a complete rebuild on my 400. Although I have learned a lot I still have a few questions.

This engine will be going in my 78 F-150 mud truck and I want the best off road perfomance I can get. I am not at all worried about streetability, just pure offroad power. I know which cam and pistons(Badger) I want to go with. Now my question is in the machine work. Should I go ahead and have it bored .30 over do a valve job and maybe have the heads shaved a little or just leave the heads alone. Also should I ahve all new bearings put in while I have it apart?
You guys are the experts so any advice you can give will be greatly appreciated. If there is anything else that I should do please let me know as this is the first engine I have rebuilt by myself, I promised I won't be offended by anything so fire away!

 

if your going with the badger flat tops I would not mill the heads the unless they need it. keep it pump gas friendly. there is power to gain in some minor head work, search for that info here if you haven't allready.
new bearings is a given. going .030 over bore will benifit the new cam and improve engine response. if your doing the assembly part yourself have the machine shop check the block and crank, do the valve work and install the correct valve springs for your cam, install the cam bearings and new freeze plugs. then go from there. and since its your 1st rebuld I would have a friend with some experience help so that you don't have to learn the hard way from any mistakes. cost can add up quick but the more you learn the more you will save by doing yourself on future builds.

 

Since you are in Ohio Sunoco Ultra 94 octane gas is available or BP 93 octane, although it is about $0.30 a gallon more than 87 octane. Depending on how the block measures out, it will probably need to be decked and the heads trued. That will give you a little higher CR. My crank had to be turned down to .010 on the main and rod journals. I had the rods resized, mains align bored, cylinders .030 over using a deck plate. Normal procedures. Since you seem to be interested in RPM's I would have it all balanced. That is the only thing I did not do that I wish I had. The valve guides will probably need replaced and more than likely the exhaust valves due to high wear on the shafts. Valve seats should be ok but have them checked and a good 3 angle valve job. Check with more than one machine shop about prices and how they do the work and ask others that have used them what there work was like. Fowler in Columbus would be a great one to look into but may be to far from you. Have you read the Hot Rod 400 torque engine build up? Heavy duty push rods and at least heavy duty rocker arms are a must. I used Crane versions and they were much thicker than stock. There may be roller style replacements that don't require studs. My engine saw lots of high rpm's and lasted over 120k miles. I had forged TRW pistons which were not flat tops. Had I known flat tops were available I would have used them.
No internet for info at that time. I like a mechanical secondary carb over vacum secondary carbs. I would go with a good ignition system. If you use the Duraspark then you will need to modify the stock distributer because it will keep advancing the timing as the rpm's increase. I cracked all 16 piston skirts and a couple broke off. I am assuming from the cylinder firing while the piston was to far down in the bore.

 

Everything sounds good in the responses you've gotten except that I would not decide about boring, or turning of the crankshaft until the machine shop has measured everything.

When rebuilding an engine it is impossible to know what is worn out until you get in there. You might find that the bores will accept rings and be good to go. If you want to change pistons, then you will need to have the block bored and have the pistons ready for the machinist so that he can fit them to the block when boring.

For your purposes, you will be able to go with a little more cam, but remember, this is a long stroke, low rpm torque motor, so don't cam it for a high rpm redline. I would think that you would not want to go any more than about 225 degrees duration at .050 valve lift. 230 degrees would be the absolute top limit.

As the other guys said, don't mill the heads any more than necessary to straighten them since you are using the flat top pistons. In fact if the heads are straight, and there's no reason that they shouldn't be, then don't cut on the surface at all.

Keep us posted on your build.

Good luck,
Doc

 

I would get the blocks align bore checked & the rods reconditioned.