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Advice on 400 value

5K views 137 replies 14 participants last post by  armyadarkness 
#1 · (Edited)
My 1970 is a few weeks out from having it's driveline completely updated. Going in is a fresh 428, a rebuilt M20, Yukon LS and 3.55s. I'm doing a CVF serpentine conversion on the 428 along with DUI HEI, DUI 1 wire alternator, Eddy carb, FlowKooler pump, Carter fuel pump, etc. So the 400 that's in the car will be coming out complete from oil pan to air cleaner. She still runs strong although the Quadra Jet and points both need some TLC (or replacement.) I didn't bother after buying the car a couple months back since I knew it would all be updated in short order... The motor has an Edelbrock Performer intake and a mild cam (don't know the specs... just going by the idle). It's not consuming oil or smoking and has 40psi of pressure at idle / 60 under load. Runs cool at 160 (new Griffen rad is helping with this.) The motor also has 6X heads into stock manifolds.

Anyways, the shop I bought the rebuilt trans from is taking my M20 back as a core and giving me decent money for it. Now I'm trying to figure what to ask for the motor? I know it's an unknown so we don't know the condition of the internals... But I'm just trying to figure what it's worth if I pop it on CL or FBM? I'm not looking to squeeze every last penny out of it. I just don't want to scrap or leave behind a decent 400. I haven't looked at the date code or casting number but it's a WT block. Any thoughts or advice on value? Thanks in advance guys...
 
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#51 ·
They didn't put all the hinge bolts in correctly because it makes the door harder to square up. That is what took me so long last night. Yes, there is plenty of things that are wrong with the car and yes, there is a lot of "while we are in there" going on but I'm having a (mostly) good time. I could have just bought a modern Camaro or Challenger and called it a day but that's not what I (we) wanted. Since my 69 Camaro I've owned any number of sports cars, ATVs, Sleds, RVs, a boat, PWC, etc. I had been purposely putting off skinning my knuckles again for as long as possible and part of me thought it would never happen again. But the wife pushed and I jumped and here we are. Right back were I was at 19 with that POS Camaro... starting from scratch...

I think the thing of it is for me is... I'm a very particular person. I am not starting from scratch because I'm trying to save money. I know all too well that it costs more to build than to buy. But for me it comes down to personalization. I didn't want a numbers matching car that was done or even a restomod done to someone else's taste. I wanted my car. (Kind of like building a house vs. buying one.) Because of this, I'll have nights like last night but in the end, that's what I signed up for and hopefully the end result will be worth the price of admission... 🍻
 
#54 · (Edited)
Preaching to the choir, sounds exactly like my story but less toys. I sold my two goats for a nice downpayment on a house and put the thought of cars away and also thought I would never have one again. We put our time and money into kids and our dream of buying property and building our dream house before our oldest started school...mission accomplished but then it was doing everything to the house by myself i.e. landscaping, patio, finish basement, build bar...for medicinal purposes 😉 Then the dreaded college tuition of two which strapped us for 6 years, but I never lost the bug. I would look at cars sometimes and freak out at the prices and thought I'll never have one, I would feel selfish spending that much on me but I married an angel that said go for it once the last tuition bill was paid, then I found this car exactly 30 years from selling my first two. She said you gave up the cars you built and loved for us and put everything into the house and kids...but I still wasn't sure and almost got sick when I won the bid ! Little did I nor her know it was just the entrance to the rabbit hole 😀
 
#62 ·
I guess the 2k mentioned by @Duff on the first page is a good place to go out based on all I'm seeing. Something is worth what the local market will bare. If it's fair, someone will jump. If not, I'll get the message and adjust. You can always adjust down if need be but can never go up... Oh, and just remembered... It will come with both a flywheel and a flex plate.
 
#65 ·
I'd price it high and hope for "that person" who really wants that year/numbered block. If you don't find that buyer you get to keep it and never feel bad you sold it for less than you could have. Did I mention you may get to keep it. I'd keep it, hands down.

If my 67 born with block would be junk...I'd pay $1000 more for the right month and year numbered running engine assembly compared to one that was just close. Even if I just needed a block. All the extra parts are great to have as spares or sell them off piecemeal and make most of the money back.

If you think a good price is around $2K, start at $3K. This gives you room to haggle, keeps the tire kickers at bay, and a good running engine carries some extra weight.
 
#71 · (Edited)
My original plan when I bought the car a couple months ago was to (over)build the 400 that's in it. So, I got to putting together a dream parts list and getting everything in my cart(s) to order. First reality check was something mentioned a few posts back. The cost. Holy lord was it adding up quick vs. a SBC build. However, that wasn't insurmountable. Availability was. Roller cams are near impossible to find and they are indefinitely backordered from most companies I was considering. To have a back order date is one thing but to be told over and over again that they couldn't even give me an estimate was unsettling. Then aluminum heads. Kauffman is out 4 months. Edelbrock is out til late December too. And that's where the short list ended. So, in lamenting my situation with my machine shop / engine builder, the owner asked me a question that took me off guard. He said, hey, if you don't want to wait until spring, would you consider a built 428? I asked why? He said he had built one for a customer right when Covid started. The guy provided the engine and many parts. He then did all the work and supplied the remaining internals and built the motor. He called and left a message that the motor was done. He called again once a month for a year. Then once every 6 months for the next year and a half. He never found an obituary or anything but assumes the gentleman passed away. So, after a couple of years of his money and shop space tied up, he's decided to sell it. At first I was reluctant as I wanted my motor exactly the way I wanted. But then I got to thinking about 2 things... "Exactly the way I want" would cost me 3 times as much and I'd be waiting to do it til next year. Having the attention span of the average gnat, I dropped a deposit on the 428 along with a few parts to make it my own and we're off. The builder wants to run it in on his stand before I pick it up and the shop doing the R&R is out a couple of weeks so that's as long as I have to wait as opposed to 2023. So, that's how I ended up with a 428...
 
#68 ·
FWIW, I paid $500 for a (poorly) running standard bore 1973 400. Complete motor, but I only wanted the block. This was about 8 months ago. If someone wants that particular date or casting code, then it would be worth more to them. If they are just looking for a builder, then less.
 
#72 ·
Ah ok, makes sense and maybe I missed that. When my motor went south I had sticker shock too, if I wanted 500hp it was around 15k and that was in 2018! So when I saw this Butler 461 on ebay for 8k ( negotiated it down to 7500.00) with receipts and dyno sheet I jumped on it. I feel very fortunate to have found it, right time right place 👍
 
#73 ·
Holy!!!! That's a steal! Congrats on that find man... I was looking at a full Butler build too but that was pushing 20k. I got the 428 for 5k. No, it's not a 600+HP monster but that other 15k can paint the car at some point... Or buy that square body GMC the wife keeps asking for...
 
#76 ·
You got it, it dynoed at 472hp 526tq and the guy decided he wanted 600hp for his Firebird and didn't install it. I changed out the intake to a Performer RPM, put an 850 Quickfuel and 1.65 rockers so maybe I'm close to 500hp and believe me it's scary enough. I have big drag radials and lift bars but still can't keep it straight. Big numbers always sound good at the car shows and I'm guilty somewhat but I'm perfectly happy with it.....unless it doesn't perfom well at the track 🤣 I also had to put a ton of money into the driveline to support 500hp like a 3K trans, 500.00 driveshaft a 2100.00 rear end. So down the rabbit hole deeper and deeper...my wife works 32 hrs a week and tells everyone it's for my car....I plead guilty your honor and hope the court has mercy on me.
 
#82 ·
I'm sorry, Jim. I apologize for being wrong.

Jeff
No apology needed. Just get out of the 1980's and up to speed with the new millenium and all the available speed parts of today that were not available back then, or at really high costs to most of us. Maybe with all these issues you speak of is why many are going to the LS swap.

Read the page post, saw nothing to the advantage in using a 400 block over the 455 except for the mention of "thin" cylinder walls - which can happen to ANY block if there is core shift or rust/pitting in the coolant side of the cylinders. Shouldn't every 50 year old block be sonic tested before you put 8k-10k-12k into it? Even stated no problem with the larger journals unless going over 6,500 RPM's - who plans on building any engine for the street to consistently hit that number, that is a race engine, not a street engine.

Note that much of the improvements are based on weight - or removing it. Today it is easy enough to get lightweight forged pistons/tool steel pins and light weight forged rods. Want to get the engine to rev quicker? Install an aluminum flywheel and 4.88 gears.

David Butler stated, "Core shift can vary run to run, so we check every block casting individually before using it in any application, but we have found that no one 400 or 455 block is better than another beyond the well-known issues with the 500557."

Any Pontiac block has limits as the Pontiac engineers did not design the "everyday" engine to be used for big HP race engines. When they did, then the engineers designed the parts to handle the race use - forged parts, 4-bolt main blocks, special flowing heads & valve train, special carbs, beefed blocks, solid lifters, high volume/pressure oil pumps, just like all the other manufacturers did.

The 455's larger journal size could not have been too much of a concern to the engineers. Seems their concern was more in way of handling the torque they produce - so in went the M-22 and the Chevy 12-bolt so those parts that held up behind a 400CI would not break behind the 455.

Some blocks can accept a larger overbore, other's can't - but you won't really know unless you sonic test the block. Some swear by it, others don't do it. Some swear by honing plates, other's don't. Some swear by hard-block, other's don't. There are no absolute statements or guarantees when it comes to engines and engine builds, only possibilities, all of which can typically be checked or verified - and then there is Murphy's Law. ;)
 
#98 ·
"You don't tug on Superman's cape.....you don't spit into the wind....you don't pull the mask off of old Lone Ranger
and you don't mess around with Jim!"-------James Croce
Well, my name is Jim, and I'm an idiot, so whenever you wish to be right in a conversation, I'm available in the evenings, M-F
 
#78 ·
Exactly, and up until the last few years when my back went out I did everything myself on the house, neighbors would spend 50k on there basements or paver sidewalks but maybe that's why my back is not great so I have to start writing checks now. Also we were smart with our money and didn't live beyond our means since we've known each other but people don't see that and we've lost friends over it. You mentioned the Ford your wife wants I think you should suprise her with it trust me. I felt so guilty I found her a 2013 purple Challenger that she has dreamed about for a Christmas suprise. I call it the purple IRA but I have no more guilt and I have never seen her so happy and cry so much, not even at our wedding 😄 of course there's the shoes and close that come every week...and a few diamonds and the beach once a year but I'm sure I'm still ahead 😉 Well I've certainly derailed this thread, sorry.
 
#79 ·
Nah, it's all good man. Sounds like we are both lucky men. I am extra blessed as my wife is into the things I am into. When brown santa brings cardboard boxes to the door she demands to know what's in them. Not because she didn't approve the purchase but because she's as into the build as I am.

As to the truck, it's on the list. I keep scrolling through FB nightly trying to find a second "barn find...."
 
#83 ·
I'm thinking Baaad's sale price is a good indicator on what you can expect to ask and possibly get. Maybe Pontiac blocks/engines/buildable cores are plentiful elsewhere, but they are scarce in New England. When mine grenaded a couple years ago I didn't think the engine coming out was rebuildable (after disassembly I think it may be so it's sitting wrapped in a corner now). I started out looking for a good core locally. The only engines that came up over the course of a 2 month search were two that looked like they had sat outside for 30 years and were priced close to $2000. I'd try to sell it running in the car and ask around $3k or so. If you think you're a month out, try selling it now and negotiate that it stays in the car until you have the other engine ready to go in.
 
#106 ·
Sweet! I actually forgot about the trailer so make that 7 different makes. We have a strange mix here. My oldest is an import car guy. Some are turned off by this but he has a lot of wrench time on some of his cars.

1970 LeMans Sport
1981 Corvette (dad's)
1994 Mustang GT (running crappy right now, needs work)
2002 Miata (oldest son)
2008 Cobalt (younger son)
2018 Hyundai Elantra GT Sport (oldest son)
2019 Honda Fit (wife)
2020 Colorado RST
Big Tex car hauler

My garage only holds 2 cars so my driveway looks like I'm running a used car lot.

We have fallen far away from valuing @System 's engine for him.
 
#111 ·
Here's something Idk if you thought of, what if there's a problem with the new 428 and you've sold the 400 now you have nothing. What's the machine shops warranty and do they cover a motor you installed? You said he's going to run it on the stand, I would be there and video it, is he breaking it in too? Sorry to be a pessimist but we had a member solar68 that had a problem with a new build last year. Just a thought that maybe wait and see if everything is good to go with the 428 before you sell the 400.
 
#108 ·
My take on the small journal blocks is indeed from past experience in the 1970's and '80's when no aftermarket parts were available.
The consensus then was that the big journal cranks tended to spin main bearings at high rpm due to the oiling characteristics of the big mains....friction increase and oil wedge build up, IIRC. In the day, I ran into several 428's and 421's with spun mains from revving too high or sustained high-ish rpm. A guy I know lost the original 421 HO in his '64 Catalina driving down the highway at the normal 3500 rpm (3.90 gears/4 speed). Spun a main.
I have not run into 455's personally with this issue. The take-away was that a 400 with a stroker crank was more durable than a 455 with a stock crank. I like the more metal in the 400 and the less friction, along with slightly thicker cylinder walls. Of course, if I ran across a real-deal 421 HO I would absolutely run it in my '65, as nothing sounds as cool as '421'. The 428 I used to have in the car back in the 80's had crank oiling issues and bearing failure from me revving it too high for too long on a commute. YMMV...
 
#112 ·
It's warrantied for a year, and yes, he's breaking it in at his shop. He wouldn't warranty it if he wasn't the one to run it in and break in the cam. Yes, it's warrantied through him despite being installed at an off site shop. He is a machine shop only and doesn't do R&R. The shop doing the R&R actually works with him frequently on projects like this. So, they are even coordinating pickup up the motor for me and getting it set to install before I bring in the car. I'm not too worried about something going wrong. Even if it did, I wouldn't drop the 400 back in for the time being. I'd wait for it to be fixed...
 
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