348 into a 380 cu.

[Ridge Overholt]

I have seen a lot of things on the transformation from a 348 to a 380 cu. I need to know what's involved. What do I need to bore the walls out to. What pistons do you all recommend? what rods? what crank? Do I have to clearance the bottom of the cylinder walls for crankshaft throw? Do I have to get new crankshaft main bearings journals? Or any other things that would be good to know. Any information would be helpful.

 

[LMBRJQ 60]

Others will reply in more detail im sure but essentially it is a 348 block with 409 crank. My understanding is that no clearancing needs to be done. Can use same rods but stroker pistons.

Steve

 

[Tom Kochtanek]

A stock 409 crank slips right in place of the former 348 crank and offers a quarter inch of stroke. I went with BBC rods and had custom pistons ordered through CPG (he had a gaggle of "stroker pistons" on hand at the time). I went with .060" over Ross forged pistons (from Aubrey).

Since it's a rebuild I would go with all new bearings and gaskets, etc,

We call it "the poor man's 409" and it will perform well depending on what you do on the top end with the cam, heads and intake .

Good luck!

TomK

 

[303Radar]

If you can identify your budget and flexibility, there is enough knowledge to help you maximize performance for your budget.
Some costs are fixed such as boring, checking block integrity, etc. Other costs are highly varied, such as pistons (thinking $700 - $1100), cam shaft, head work (rockers, etc).
There are a couple of threads dedicated to rebuilding and they have part numbers and slightly out of date prices. However, these are great starting points for budget and setting expectations.

 

[CDNpontiac409guy]

As the guys have mentioned, it's a bolt-together ( thanks, Tom ). I personally feel that it is the ultimate-budget build performance combination, when using small port heads. Only expensive part, are the pistons. For the best efficiency and reliability, custom made forged, lightened pistons are highly recommended. You can use standard aftermarket BBC rods... or for that matter, with the 3.5" stroke, and light pistons, I see no reason why a good set of stock BBC rods wouldn't be just fine.

 

[wally72974]

I was told (by a old timer engine builder) that stock BBC rods are good to 500hp. If you plan on going over 500hp you should look at performance aftermarket rods.
Anyone here think otherwise?

 

[wally72974]

A stock 409 crank slips right in place of the former 348 crank and offers a quarter inch of stroke. I went with BBC rods and had custom pistons ordered through CPG (he had a gaggle of "stroker pistons" on hand at the time). I went with .060" over Ross forged pistons (from Aubrey).

Since it's a rebuild I would go with all new bearings and gaskets, etc,

We call it "the poor man's 409" and it will perform well depending on what you do on the top end with the cam, heads and intake .

Good luck!

TomK

I too also ordered pistons form Aubrey. I like the pistons I got from Aubrey but it took 4 months to get them. (he did not have them on hand) They were for a 380 cubic inch 348 stroker build. Just 10 to 1 comp and .030 over pistons.

 

[models916]

The only problem I had with the stock BBC (454 dimple) rod was the length variance from one to the other. I made the quench very tight and the difference between the rods would not let me use them. I used Eagle SIR big block rods. All eight measured exactly the same.

 

[61 Bubble]

Ridge, your cheapest way is to by my 380. Not a perfect build but pretty damn good for what I want out of it. Like I said I could sell you everything you need to "bolt-in" the motor and trans. Now seeing that you want or need basically everything (headers, rad, bellhousing, clutch, T-10 trans and even driveshaft) I would be willing to make an offer on the WHOLE package so it's a bolt in deal, say $6,500.00 and you take care of shipping. Or if you want just a motor, that's fine too.

 

[Ronnie Russell]

That is one swingin' deal for the whole package. Plus, saving about 6 months build time on the engine.

 

[scott hall]

Yea what Ronnie said

 

[wally72974]

Ridge, your cheapest way is to by my 380. Not a perfect build but pretty damn good for what I want out of it. Like I said I could sell you everything you need to "bolt-in" the motor and trans. Now seeing that you want or need basically everything (headers, rad, bellhousing, clutch, T-10 trans and even driveshaft) I would be willing to make an offer on the WHOLE package so it's a bolt in deal, say $6,500.00 and you take care of shipping. Or if you want just a motor, that's fine too.

A professionally built 380 engine could run you anywhere from $2,000 to $4,000 just in machine work and labor. Add to that the time you could spend driving it instead of building it? Hell yes to what Ronnie said. (Ronnie is smarter than me and I ain't afraid to admit it)

 

[Tom Kochtanek]

That is a good price. I hate to admit it, but when I built my 348 stroker years ago I ended up around $7500 just for the engine. It's a 1961 date coded FA suffix block with 1147 heads (upgrade from the 379 heads that came with an FA engine) and a correct tripower intake. Looks good, even with those little pot air cleaners on it .

Good luck!
TomK

 

[61 Bubble]

Guys I know this is a KILLER deal!!!!!!!!!!!!! I have already started getting my other stuff together and its waiting for someone to step-up. There are a few members who want it, just funds are tight.

Tom, from Aubrey's site (since this WAS HIS OWN engine), it's looking like this would be around the $8,000.00 range for the motor alone new. Tom I also have the correct Tri-Power intake and carbs with everything BUT no air cleaner, rebuilt for this as well, if someone wants it too.

That's my bottom line, NOTHING less price.