A forum search didn't find anything recent. I'm looking for a 64 - 66 401 or 425 nailhead and an ST400 transmission for a future project, but I don't have any gauge of fair market value. I want to get a fair shake and also not offend a seller with a low-ball offer to where I lose an opportunity. I've located a complete (oil pan to intake, water pump to flexplate) 425 and ST400 w/converter combo out of a 1966 Riviera and will be meeting the owner soon to look at them and hopefully make a deal. It's a "best offer" deal, and we haven't discussed price. The owner knows nothing about the engine and transmission aside from that they turn over by hand and came out of his project car. He's unwilling to pull the oil pan or valve covers, so the best I'll be able to do is turn it over and peer through the intake runners, distributor hole, and breather holes. The speedo is missing from the car, so no estimated guess on the mileage. The chassis is already restored, so no guess on the mileage there either. From the photos, the engine and transmission are dressed stock with typical aged paint, dust, oil buildup but nothing that would suggest they are greasy unmaintained junkers. Questions for those in the know, preferably on Rocky Mountain region pricing: What is an unknown-condition complete 425 nailhead worth? What is an unknown-condition complete 401 nailhead worth? What is an unknown-condition complete ST400 w/converter worth? Thanks for the help.
I'm assuming it has the starter, you should be able to rig it to spin the motor and do a compression test and maybe even check the oil pressure. Not in your area, but I'd guess a value of between $400 to $800 depending on what you find. But I'm not jonesing for a nailhead so I may be low.
From your point of view, you have to look at it as rebuilder for the engine(s)/trans. Hopefully he understands that as he is prohibiting you from a closer inspection. So he either knows something or not, but you are the one footing the bill not him .
I'd be careful with a 425...it can probably only go .030 over before having to be sonic tested to see if it can go further. A 425 is a pretty thinwall casting compared to most older motors. If that 425 is already. 030 over...it might need sleeving or similar expensive work to rebuild it. If you don't have a bore camera...they're cheap at Harbor Freight...like $75 and it can save your hide..
Thanks for the input and caution on a 425 vs. a 401. I'm thinking $400-$500 for the engine and $300 for the transmission would be reasonable.
And the answer to my question is $800 - $1,000 in my area. Today, I picked up a standard-bore complete 425 and matching ST400 switch-pitch transmission w/converter pulled from a 1966 Riviera for $800. I must say, having wanted a nailhead since I was about five years old flipping through my father's old car magazines, it's pretty rewarding to go out into the garage and see one on the stand.
They are very expensive to rebuild so my suggestion is to only pay core price for something you plan to tear apart. Once you’re in there, the list gets long.
Core price seems to be about $500 for a complete engine and $300 for a complete ST400 switch-pitch transmission. At least in my region, the supply of 364/401/425 nailheads is very scarce, so core prices are higher. 65-66 ST400 switch-pitch cores are even scarcer. In the HAMB classifieds, people are asking between $500 - $800 for core nailheads engines alone all over the country. Ebay is more after shipping. You got me curious. What are your comparison engines for expense? Taking SBCs off the table since they are unfair outliers, I beg to differ on a 401/425 nailhead being "very" expensive to rebuild stock or mildly hopped up compared to most other "unique" engines (Ford flathead V8s, Caddies, Olds, early Hemis, Chevy 348/409--heck, even a 351 Windsor). People likely won't be able to buy a rebuildable, virgin, complete core for one of the above engines for less than $500. Most of these engines have little or no aftermarket head choices, so machine work is more extensive since the factory heads will need rebuilding.
If your not to familiar with nailheads, checkout russ martin's web site. www.centervilleautorepair.com
Thanks, I've read the entire site researching nailheads before looking for one. Most of my parts from the above $2,200 tally come from him.
I just picked a '65 425 and tranny combo up from California..$1300 for all with pulleys, brackets, manifolds..ect. Looks like it might need a sleeve but all std. On a month waiting list for the machine shop...
Thanks for the brake down on build cost. I recently purchased a 66 225 with a 401/400 running and driving for the drive train. Pretty dang nice car with 80k miles other than the interior being trashed by the sun and rats. I always wanted one and figured I would go through it some day. Might even drop it in the 53 and do away with the tube some day.
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