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1970 GTO / 400 / 4 speed
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Discussion Starter · #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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1970 GTO / 400 / 4 speed
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208 Posts
Discussion Starter · #3 ·
Thanks @Duff I have just that video on my phone from this morning. I think I'll take a second while driving too to give a bigger picture. I'm wondering if I should buy a cheap Harbor Freight engine stand so it doesn't look like I just tossed it onto the floor? I'm going to bring it home on a tire in the bed of the truck but that won't look great to a potential buyer when they come to see it in the garage.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #5 ·
LOL, sure thing... 🤣🍻

Hey, where exactly are the date stamp and casting # near the distributor? Is it really hard to see with the motor in the car? I'd like to finish my research on what exactly this 400 is...
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #9 ·
I believe the M20 will be fine. I think lots of times folks get hung up on ratings. Same happened with my TH350 I had behind a 400 small block in my 69 Camaro back 30 years ago. I had that motor really built and threw a 140 shot of nitrous on top of that. Ran 11's and I beat the snot out of it every weekend on the street. The only thing I ever broke in the driveline was a rebuilt 8.2 GM posi after almost 4 years of this abuse. Now, that's anecdotal evidence and I may grenade this M20. However, after returning the old one to the guy who built the replacement, I'm only out $850. So, if that $850 turns out to be money spent poorly, I'll get on AutoGear's waiting list for a wide ratio M22 and pony up the $2300 they want... I guess time will tell... 🍻
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #12 ·
I was thinking that about showing it in the car too @Jared . I just didn't want to do it too soon as I'm still a few weeks out from my swap. I would be happy to show it to you though...

On the M20 and 10 bolt, I agree completely. Mine is not an over the top built motor and I'm not dumping the clutch with drag radials on. When I talked to Mike at Ram clutch, he said that so many guys go strictly by HP ratings and estimates. He said, while that might be safe, it's often completely unnecessary and guys end up with a leg shaker of a clutch because they over bought. He said long before something breaks or the clutch slips, the tires will break loose.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #14 ·
Oh, so many ways to spend my money...LOL. Now to get the 400 sold and try to recoup what I've already spent. I'm up to the point where I have about the same into the car as all my current upgrades and mods...
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #15 ·
Oh, hey, no one replied to date and casting numbers. Easy to see when still in the car? I took a preliminary look and came up empty but for all I know, I'm looking in the wrong spot....
 

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Discussion Starter · #43 · (Edited)
Get the casting date (by the casting number near distr) and 2 letter block code (right under the pass side head).
It's a WT block. What is the additional need for a casting date if I already know it's a 1969? To determine if it was used in a 1969 vs. 1970? Just went and checked. I can make out E for May and 23 for the day of the month but the last one has me stumped. It doesn't look like a 9 for 1969.... more like a 2 or an 8. (Closer to an 8 under a magnifying glass..) However, the casting code says it is a 69 so I'm not sure what to make of it.

Automotive tire Grey Wood Artifact Snout
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #45 ·
Looks like you got a ‘68 400, 360hp from a manual car. That casting code was used 68-69. Nice engine.

what heads are on it?
6X heads. Interesting about the casting code. I didn't look past 69 so I didn't realize it was the same code as 68... Thanks for that!
 

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Discussion Starter · #49 ·
It's a fine plan but I'd really like to recover the money @Jared. I may kick myself one day but right now the mission creep that's already happened in 2 months of ownership is just unreal....

Plus tonight Christine did no behave herself. I noticed a while back that she only had 2 bolts in the door hinges on the door side. One upper and one lower. Both driver and passenger side were the same. Today a set of hinge bolts came in the mail so I figured hey, it's 85 in the garage with 85% humidity and I've already showered and put on nice clothes for the day but... how hard can it be to add a 4 bolts to each door right? Needless to say, my clothes are in the laundry and I just got out of shower two... and I only added 4 of the 8 missing bolts... and scratched the driver side door with some miss adjustment on try number 397.... So, she is on the naughty list tonight.
 

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1970 GTO / 400 / 4 speed
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Discussion Starter · #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... 🍻
 

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Discussion Starter · #53 ·
Sooooo.... I've gotten a ton of great info in this thread but the one thing that keeps being left out (other than the 2k suggestion on page one) is the reason I started the thread... A listing price... 🍻
 
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