Hey Guys,

I am looking to build a stout, but reliable torque machine of a 400, I want it to last 100k miles, but after my last experience with the machine shop and my 355 and getting everything in the sun done to the block I want to know what is needed to do it right, but I will never see over 5000 RPMS. Trying to keep costs down, but I dont mind paying for quality to do it right.

All of my parts are used, so I want to get them back to stock if not better.

Clean, Inspect, and Magnaflux
Zero Deck
Bore and hone with Torque plates
Balance short block
New Bearings
Brass freeze plugs
Install Cam Bearings
Drill and Tap Oil Gallery
Install new oil passage plugs
Install new oil pump, pan, screen and pickup
Install ARP main studs
Crankshaft Magnafluxed (it's already been turned)
Crankshaft Polish and chamfer
Shot Peen Connecting Rods
Polish Connecting Rods
Re-Bush Connecting Rods
Hang and Align Pistons

Anything I am missing? Anything you would remove. Unfortunately living in So Cal, the above stuff will run me about $1300, my buddy knows a guy that can do a once over on my block for like $400, but I would rather pay $900 for 50k additional miles out of the block.

Could really use some help here as I am racking my brain...

James

 

Don't zero deck the block. Only shave what's required for a flat sealing surface.

Main studs are overkill. Save your money and align hone if necessary.

5.7" rods simply checked & reworked makes more sense. That will require proper pistons, but they're available. Polishing and shot peening is pure overkill.

If you really keep it below 5000 RPMs, it should last a long time. I've seen a 400 with over a quarter million miles on the stock bore. Using a quality synthetic oil is a very good way to insure getting the mileage out of it.

 

Since it sounds like your are doing a NA engine and keeping the revs down...

Clean, Inspect, and Magnaflux

If the engine came from a runner and the engine ran fine, you do not need to Magnaflux the block. If there was a crack, coolant would be leaking already. I have rebuilt multiple blocks, and NEVER had a crack give me any grief.

Zero Deck

Never done it. I've measured the deck to make sure that it is up to spec. Again if there was a warped deck on a runner, antifreeze/compression would be leaking.

Bore and hone with Torque plates

Yes, but if you want to cut cuts, honing without torque plates MAY cost you a horsepower or two.

Balance short block

With new rotation assembly, this is a must!

New Bearings

Must do!

Brass freeze plugs

Factory steel one have lasted hundred thousands of miles.

Install Cam Bearings

New ones

Drill and Tap Oil Gallery

Not sure what you mean, but CLEAN every oil gallery with a rifle cleaning brush.

Install new oil passage plugs

Sure

Install new oil pump, pan, screen and pickup

Old pan can be cleaned up and installed

Install ARP main studs

Don't need studs, check main bolts for stretch. Also if the pre-existing bearings had normal wear, then align honing the mains is not necessary.

Crankshaft Magnafluxed (it's already been turned)

Again, if this crank was in a runner and it didn't break, there is probably not a crack there. You could chance not Magnafluxing it, but early detection of a crack would save you a lot of time.

Crankshaft Polish and chamfer

A simple operation that you can do yourself. Plus if the crank has been turned, it should have been polished.

Re-Bush Connecting Rods, Shot Peen Connecting Rods, Polish Connecting Rods and recondition and new rod bolts

After all the effort and costs in recondition old rods, you could pick up some NEW rods (eagle) at $200/set that have been thoroughly checked.

Hang and Align Pistons

Are you using floating pin or pressed pin?

Degree the camshaft

Blueprint it, that is verify that are measurements are within spec.

Do frequent oil changes one built.


The above rebuilding methodology has worked successfully on multiple engines. Most note worth include a 10 second 1/4 mile big block and 450 hp blown SBC (boat engine).

 

The Engine had a bad rod knoc, but was running, however I am not sure what internal damage may have been caused. We are going to pull it this weekend. So I am going to still get it dipped and have them magnaflux, and honestly I am thinking of having it pressure tested and sonic tested. The block has about 200k miles on it and I am not sure how many times it has been rebuilt... I dont want to go put $3k into a buildup only to have the block crack after 3k miles

Zero Deck - I have na idea of what this process does, I know they did it to the 355 so that I had an exact compression ratio with the heads and to make everything flat, but if it doesnt help longevity at all, than that saves me $200 right there.

Bore and Hone with Torque plates - I will probably still have them do this even if it is not necessarily needed to get that better job done.

I will of course install all new clevite77 bearings all the wayaround, mains, rods, etc...

Drill and tap the oil gallery - This is where they make the oil gallerys larger and use larger plugs, supposedly for better oiling.

I have to thank you guys... I went from $1300 machine shop down to probably $500 - $600. To much trick stuff out there to do, and since I rev my 355 I did it, but with this I didnt want to go through $3k in machine work again lol

James

 

If there was a rod knock due to wiped out bearing, then the block should not be affected. Again, if no anti-freeze is leaking in the oil, there probably (99.9% chance) is no crack.

Since this block has been rebored, the diameter of the cylinders might be too big to rebuild. The first measurement should be all the cylinder bores and determine what overbore it would take to clean up the cylinders.

 

Yeah that is what I am afraid of that it has already been taken .030 out, and that it would take going to .060 to clean it up. That is too close for comfort to me.

James

 

Best to measure. You could get away with 0.040" over and 0.060" over is possible, but then one needs to sonic check the thickness of the cylinders.