425 Build

would it be possible to get this scaled before you install it?

say, scale the entire run stand with the engine installed and then pull the engine and scale the run stand without it?
That might be interesting, but I don't have the capability. While there might be somewhere, I would then need the ability to load and unload it from a pickup. Unfortunately the truck I had with a small crane was totaled a year and half ago:(
would it be possible to get this scaled before you install it?

say, scale the entire run stand with the engine installed and then pull the engine and scale the run stand without it?
Here you go...:) 674 pounds.


The weight of 674 pounds was after the motor had been run. It has full oil, no oil in the power steering reservoir, water had been drained from the block plugs. No air cleaner, only one fan belt, included hoses.

Weighed as in the picture. Included A/C compressor, heavy OE starter, exhaust manifolds with heat riser.
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thanks muchly.

~675lbs puts it quite a bit lighter than the mid 700s i typically see quoted for 401 / 425. but that's still around 40 lbs heavier than what the 455 is supposed to weigh. all in all, not a huge penalty for a more robust oiling system and forged crank + rods.

that REALLY makes me wonder about putting 455 heads on a Nail block. :clonk::clonk::clonk:

i'm guessing the 401 weighs more?
erm, i would guess the 401 *has* to weigh more, although perhaps not much. piston is aluminum, cylinder wall is cast iron.

CI weighs more per volume than AL does.

therefore, every thousandth of bore reduction means less Alum and more CI. even if the cylinder bore in the smaller displacement is cast to a slightly smaller dia, you still have more CI in the deck.

therefore, if the casting is same in almost every other respect other than bore size, they would have to take CI out of some other part of the casting in order to maintain weight.

worst would be if they just used the same casting but simply bored the 425 extra large.

i'm certainly not expecting it to put a 401 into the mid 700s, but it's just something i'm curious about.
Here is what I hope is the final build for a transmission kick-down switch bracket for the 2X4 set up. Maybe someone else will want these dimensions. I would have liked the correct "66 bracket, but a reasonably priced one has eluded me for now.



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I just got through doing a 401, complete engine. Bored to 4.215, with intake & exhaust manifolds, one of my "Mini-Starters", alt, belt, hoses, brackets to have a complete running engine on an engine start cart was 638pds.

Tom T.
That make 37 lbs. less. Mine had an a/c pump complete with brackets, that and your mini-starter would probably account for the weight difference.
no power steering?

welp, sorry i doubted you Tom. that's **** sure close enough to a 455 in weight that it raises serious questions about why Buick weakened the BBB design so much.

put alum heads + alum intake + headers + mini starter and you'll be well under 600lbs with a forged rotating assembly.


New member
Wicked car! Looks like AFB's on there, did you manage to find an original dual quad setup or are you running some grouping of nailhead carbs? Having a bit of trouble tuning mine, was curious what your tune was looking like as your engine is similar to mine otherwise.


New member
Wicked! If originals weren't going for a small fortune I'd go that route, but having fun making two standard AFB's play nice! I agree, the kickdown linkage is absurd, I'll be making my own as well. Since my car doesn't have a switch pitch it's pretty non-critical.

Beautiful car, great color on it!