377 sbc

[badfast47]

May have ask this b4 but... Can u use a stock 400 2 bolt main sbc to make a 377 and it work without it coming apart ? Will have the mains and heads on studs. The heads will be aluminum with 2.100 and 1.60 valves... Pistons ? Flat top or dome don't care.

[Jim11h]

Yea it'll work. Had one long ago with 12.5:1 domes stock rod stock stock crank internal balance. I bought used from friend and they twisted it7k all time with 4 barrel on alky. I bought and ran till I screwed up reassembly and blew motor something about forgetting to torque the rod bolts the motor didn't like.

[badfast47]

I have been able to read in a couple of places the 377 isn't as hard on the bottom like a 406 for example. I would like to try one just for the hell of it.

[Ronnie9]

I have been able to read in a couple of places the 377 isn't as hard on the bottom like a 406 for example. I would like to try one just for the hell of it.

Good combo, just make sure its balanced correctly

[billetbirdcage]

It's still a stock 400 block so thin cylinder walls, weak mains to cam area are still there, as well as the steam holes in deck that will crack over to the head bolt.

Couple of things that might help it live:

1. Have block sonic checked on wall thickness before spending any money on machine work

2. Don't square the block, meaning if it's out of 90 degrees don't correct it as cutting deck differently then the head bolt holes where machined will pull sideways on the bolts/studs and increase the chances that the head bolt hole will crack over to the steam hole. You can deck it, but only cut parallel to original surface as not to change the angle of the deck to the bolt holes. Also advise the use of head studs.

3. I also like to plug the steam holes. Do this by tapping the steam holes but not all the way thru, then install a cheap grade 2 bolt and tighten until it twists off or stop once it jammed in there and cut off. Then deck the block.

4. When using spacer bearings to go down to the 350 main bearing size: Use .020 or .030 under bearings (thinking .010 is what is used when you buy them already made) and make your own. This way you can have the block align honed with the extra undersized bearings and remove all the soft material down to brass. This will make things repeatable and more consistent to reuse later.

5. Installing main caps: I prefer the stepped caps that you don't cut out the register over the flat caps. I've seen way to many of the flat caps with cut out register crack and split up to the cam right at the corner of the new register due to having no radius there.

6. Think about a short fill on the block, you can do this yourself but need to do weeks before hand to let it cure before you do any machine work. You can use concrete if you get the correct stuff, instead of buying block filler. (EMBECO #882, it's a special non expanding concrete)

Good luck but anything over 600 HP is starting to get to danger zone, some blocks will take that and more and others will fail shortly.

[fastford]

all that is good advice billet , one thing to add , i cant remember where we got them , my dad may have made them , but we used still spacers in the mains and aligned bored them to 350 size , we also half filled the block , just like i do the 302 ford blocks , with moroso hard block , i think this is probably the most important part , we also used a 2 bolt main block and built them both ways , meaning we put splayed center caps on some and we used just stock 2 bolt caps on some with good studs , which IMO is just as good when staying under 600 hp , and like you stated , none of them is good for much more than that no matter what you do........

[Kromulous]

I built a 380 years ago, 10 at least, and its still out there racing. 400 block, 3.5 Callies crank, 6.125" rods.

Step caps, to 4 bolt, plugged steam holes, block half filled. 350 main size, line honed etc.

It was intended to be an alky motor from the get go. Watch your cam size, you will need a small base circle. I think what Billet said is on point, this motor was right at 600 to 625, but it was one of my favorites.

[fastford]

only time i have had to use a smaller base circle cam was with a 4 inch stroke , that 3,5 stroke should easily clear a standard cam.......

[Kromulous]

Was it the bolts? that was in the way. I remember bolts being a problem, but that may of been on another Engine. Always good to check thou.

[over4T]

Billet has a lot of good ideas, including a few I hadn't thought of, but after seeing too many stock 400 blocks fail too early I just stay away from them. Pouring time and a lot of $ in them just never made sense to me and I pretty much just keep building 383s & 385s with stock 350 blocks. Had a lot of reliability and, generally, good luck with them.

My machinist usually has several, he says, good 400 blocks and is constantly trying to sell me on doing one but I just keep saying no thanks.

[fastford]

its like every thing else over4t , its according to what you are trying to do with it , i did some work for a guy that asphalt raced a limited type car that required a bone stock crank shaft , every one stuck with a 350 crank because of the junk 400 crank breaking , but my guy wanted to stay with the 400 crank because he was winning races , we finally figured out that after about 20 races , the 400 crank started to spider web(crack) so every 15 races we would swap the crank , he killed them for 2 years till they changed the rules to an aftermarket crank.......

[JustAddDirt]

If you Can find the high nickel 400 blocks they are extremely strong (for a stock 400)
I think they were in school buses, etc.
Someone told me they were a Mexican casting, but dunno if that is true information

[Lizardracing]

So where does one know if the casting is high nickle or not?

[fastford]

i have herd of this before but i dont know about the nickle part , the 509 block with only 2 freeze plugs per side instead of 3 was the best IMO , and had less core shift and most can be bored .060 over with no problem , this is the one we convert the 3 center mains to 4 bolt splayed caps, i have pulled a bunch of 350 four bolt main blocks out of school buses but have never saw a 400 in one.....

[JustAddDirt]

cool bus

i have herd of this before but i dont know about the nickle part , the 509 block with only 2 freeze plugs per side instead of 3 was the best IMO , and had less core shift and most can be bored .060 over with no problem , this is the one we convert the 3 center mains to 4 bolt splayed caps, i have pulled a bunch of 350 four bolt main blocks out of school buses but have never saw a 400 in one.....

I could have gotten bad info on the school bus part.
that 509 seems to ring a bell on it being the better blocks.