1972 Charger. 400 from factory. Have owned the car 10 years or so, never did anything to this motor. Only runs OK. My son wants to turn this into his daily driver.

Is it worth it to yank the engine, go through it, then top it with EFI? He only wans reliability. Not interested in a stroker or anything at this point.

I like knowing we are starting from the beginning is why I want to go through it. Question is, is it worth it?

I like the idea of it all sealed up, knowing rings are good, no leaks, plus I want to clean and paint the engine bay.

I've done it, some of the freeze plugs you can't get to with the engine installed, you are replacing them, right? Pull the pan, give the bearings a looking at, maybe put a windage tray in just cause you're there.

Usually the short block rings and bearings will be good if her engine was cared for and not too carboned up. The cylinder heads usually need to be rebuilt.
If you can have the tools, perform a leakdown test. If the valves still seal, it will let you know if the rings are sealing.
If the rings show they are sealing, and after removing the heads, the bores looks good, you may just want to leave the pistons/rings in the engine. If the bearings look good, just re-use the shortblock with new freeze plugs.
The timing chain is likely shot. If oil pressure is good, you can keep the stock oil pump. A higher volume pump will help maintain pressure if the bearing clearances are a little loose.
If the rear main seal is not leaking, I would leave it alone. The cheap black replacement seals don't work that well. The Orange seals work good, but are expensive.

For the heads, I would not spend the money to rebuild them.
I would look for a good deal on some small chamber aluminum heads.
The Edelbrock E-Street #5090 75cc chamber cylinder heads would be a nice upgrade. The smaller chambers will increase compression and they flow better than the stock heads too.
Add a small performance cam like the Lunati Voodoo 10230700LK (208/213@0.050" 0.454"/0.454" lift) and have a fun daily driver.
Note that the Voodoo cams use a 3-bolt cam timing gear set.
The 440 Source billet timing sets are pretty nice and good price.

Do a compression test on it, if things look ok, don't bother doing the rings on it. I've done them before on an engine that wasn't really bad enough to warrant it, didn't yield me any real improvement.

I would consider pulling it, removing the heads, scraping the carbon off the tops of the pistons. Pull the heads, clean the valves and seats, put in some new valve seals and button it all back together with fresh gaskets, timing set and paint. Of course this would be the time to add a small cam, headers, aftermarket heads, intake, etc if you wanted.

If he's using it as a daily driver, EFI will be great. Be sure to get a system that controls timing as well. Those smogger 400's and 440's need a careful timing curve to get the most out of them.

How "thru it" do you want to go?

If you are building for DD duty, fuel efficiency is likely a concern hence the EFI.

My thoughts are Stealth heads (if budget permits perhaps the new Trick Flows. Better combustion chamber, better flow) checked and corrected, zero deck pistons and as much CR as 87 reg will stand. Should be safe at 9ish:1 with aluminum heads. Cam experts will know better but I would guess a cam in the 2teens @ .050 with as much lift as possible would be appropriate.

Up to you how much further you want to go ie H-beam rods or rebuilt stock. Properly prepped stock cost goes a long way to buying new H-beams and new might be light enough to get the cast crank to neutral balance.

Kevin

"He only wants reliability"

With a 74 SSP bone stock 400-4bbl auto/3.23 was a consistent 14.2 @ 96mph car. If the compression is good, good oil pressure, I'd leave it as is.

If it runs good, has even compression, and doesn't use oil then drop EFI on it and go.

No need in pulling a good motor and introducing problems.

My problem is the stock 400 pistons are 0.120" below deck height.
This would be 8.0:1 compression with a 0.020 head gasket and 83cc head chamber, and the stock heads are likely larger than 83cc. With a 90cc head, compression is 7.6:1.
75cc Head brings that up to 8.5:1.
If you had 65 cc heads (B1-B/S) it would be 9.27:1 compression.
I don't think the poster would want to go the expense of the B1-B/S heads and offset rocker arms unless you could find some used at a good price.

Now, if the short block needs to be rebuilt, new pistons would be the cure, but now your getting into machine shop costs on top of replacement part costs.

Here, simple.

Low compresson 400 on the dyno.

yep, rings, bearings, gaskets, freeze plugs, water pump, valve job w/ valve seals, and add efi. Then change the trans fluid. anything less will come back and bite you. Should be a great ride for a kid. Gene

Here's what I'll be putting on my 400 based stroker. http://fitechefi.com/default.asp.pg-Products

There coming out with one that is good for up to 400 hp which will probably be at least $100 cheaper than what you see there.

So how much would those big valve 346 heads cost me?

More than these............

Sidewinder heads

Thanks Jim. That was sort of my point. You can get good performance from stock heads if you put the time and money into them, but it's easier for guys like me who don't own a machine shop, to just slap on a good aftermarket head for close to the same cost, and increase the compression a bit at the same time.

On the FBBO page, does anybody think the dyno numbers are high?

If it doesn't burn oil, leak a lot or have other issues I would only:
- Put a new high volume oil pump on (cheap insurance)
- Get a modern cam that builds a little better dynamic compression and has a little more lift. Call Comp or Hughes. Don't forget lifters.
- Use your money on a "self-learning" EFI that includes ignition control and an oxygen sensor. Some of the systems need a lot of AMP's on idle so choose one so you don't have to mess with a bigger alternator and all that comes with going to more electrical juice.

Now you can keep the cooling system, exhaust, converter, gearing...

I wouldn't mess with a healthy 400 even if it is a low comp slug when the purpose is daily driving. With the EFI you don't flush the cylinder walls at every start and don't contaminate the oil with gas. It will last for many fun miles

Thank you all. We are at the beginning of making decisions on what to do. I think this weekend we will do the compression check. Don't have the leak down kit, but I bet I can rent it.

With adding EFI, even the minor things we are discussing are going t be nearly a $5k upgrade if I put the eddy heads on it. Crazy how fast the price builds.

68KillerBee

I had no idea the FITech were so affordable. I thought these were still $2500.

For under $1500 I can get the fuel sump and FI setup. That is good news.

If the compression checks out, skip the heads and just do the EFI.
Do the heads and other stuff later if he wants them.

I agree fully. EFI together with a nice cam is a good start.