chevy 350 or 400? (1 Viewer)

[cody]

hey guys, appreciate all your inputs. i think i might do as woody suggests and use the parts off the 400 to make a stroker. two questions though: i have a 2 bolt main 350 block, will that hold up for the stroker, or do i have to get a 4 bolt main? and also can my stock 4 speed tranny and transfer case handle that much torque? thanks again

 

[smf]

Rebuild it!

If you can get a complete 400 free there is nothing wrong with rebuilding it. I have a rebuilt 400 with about 68k on it and I love it. I live in nevada where in the summer I see temps up to 120 sometimes and I never see engine temps over 205 and I'm running a stock 4core. The position of the radiator is the key.
I run some redline water wetter in the summer an just maintain the colling system and I have had no problems. It will make more heat due to displacement but not by much. Plus if you run it stock it should last a very long time.


If your main objective is a lower RPM high torque engine then the 400. If you wish for more revs and don't mind a loss of bottom end torque the 350, as Woody says, is a super engine.

My sb 400 specs:
GM Engine code stamp #GM3951511

year: 1970-73

code: 3951511 400

Low hp: 255

High HP: 265

Main Bolt: 4


Just rebuild the 400 you'll love it!

 

[Rice]

hey guys, appreciate all your inputs. i think i might do as woody suggests and use the parts off the 400 to make a stroker. two questions though: i have a 2 bolt main 350 block, will that hold up for the stroker, or do i have to get a 4 bolt main? and also can my stock 4 speed tranny and transfer case handle that much torque? thanks again

If you're building a 383 you're doing it for torque, right? So what's wrong with the 400?

Your 2 bolt block will do fine.

 

[Steve C]

STEVE C your info is a bit confusing????

flexplate is automatic
flywheel is stick/manual

you cannot put either on the crank 180 degrees out, crank is pinned.

This method is similiar to how they take a 350 or internally balanced flywheel and make it work for a externally balanced 383/400. BUT has nothing to do with changing the crank. DO not try this at home. NO shifting.

"I used to have a 350 in a 40 series and thought it was a little scary in term of the amount of power it had. My feeling is that something like the fuel injected 4.3 liter 6 would be a fantastic swap."

I guess it depends, again 406 sbc and looking at Big Block for one of my other fj40s. Might think about keeping the stock 6 just to keep you from being scared.

Sorry for the confusion. Maybe I skipped a few steps.

I'm assuming that 400's started as automatics, which I think is true (wasn't the 400 more or less a "station wagon" motor as originally made?)

The landcruiser needs a flywheel (manual).

The question is how to get a new flywheel to match the "imbalance" that the old flexplate had. This can be done by mounting the old flexplate and the new flywheel together on a balance machine 180 degrees out of phase. The assembly is brought into balance by weighting the flywheel. Then the flywheel and flexplate are separated and the flywheel mounted on the engine in the same orientation that the flexplate had. The "imbalance" of the flywheel will match the "imbalance" of the flexplate, bringing the engine into balance without the need for a special crank.

As far as the "scary" thing goes, if it's your car it's entirely up to you what you want to do with it, as far as engines go. My experience with the fj-40 is that it dosn't turn to well, it dosn't stop fast, its not really stable at speed, and it's not good for pulling a trailer. This isn't a criticism, but a reasonable charactizeration of what the car is. Most of the modifications that are typically done, such as bigger tires, suspension lifts, etc would make a 40 even less suitable for high speed use. For things that the fj-40 is good at, the 2f is actually a pretty good engine. Don't believe me? Look at the engines that have been put into other vehicles that are intended for off road use. Unimog, g-wagon, defender, and other landcruisers. All of these cars had pretty modest engines. The latest landcruiser and g-wagon have power, but their suspensions are much more advanced than the fj-40's.

Maybe for deep mud you do want all the power you can get though, but I'd rather have lot's of power in a car that can use it.

All my opinion though.

 

[Cdaniel]

Testimony from a long time 383 Chevy owner:
Excellent 4x4 bullet. Torque like a tractor in the rocks. Hard to stall.

Downside: Low rev limit, not real happy about highway RPM's but it tolerates it.
It's not a racer if your into stop light drags in your Cruiser.

You can build them differently for revs, but then you sacrafice the beefy low end.

 

[Rice]

Sorry for the confusion. Maybe I skipped a few steps.

I'm assuming that 400's started as automatics, which I think is true (wasn't the 400 more or less a "station wagon" motor as originally made?)

The landcruiser needs a flywheel (manual).

The question is how to get a new flywheel to match the "imbalance" that the old flexplate had. This can be done by mounting the old flexplate and the new flywheel together on a balance machine 180 degrees out of phase. The assembly is brought into balance by weighting the flywheel. Then the flywheel and flexplate are separated and the flywheel mounted on the engine in the same orientation that the flexplate had. The "imbalance" of the flywheel will match the "imbalance" of the flexplate, bringing the engine into balance without the need for a special crank.

As far as the "scary" thing goes, if it's your car it's entirely up to you what you want to do with it, as far as engines go. My experience with the fj-40 is that it dosn't turn to well, it dosn't stop fast, its not really stable at speed, and it's not good for pulling a trailer. This isn't a criticism, but a reasonable charactizeration of what the car is. Most of the modifications that are typically done, such as bigger tires, suspension lifts, etc would make a 40 even less suitable for high speed use. For things that the fj-40 is good at, the 2f is actually a pretty good engine. Don't believe me? Look at the engines that have been put into other vehicles that are intended for off road use. Unimog, g-wagon, defender, and other landcruisers. All of these cars had pretty modest engines. The latest landcruiser and g-wagon have power, but their suspensions are much more advanced than the fj-40's.

Maybe for deep mud you do want all the power you can get though, but I'd rather have lot's of power in a car that can use it.

All my opinion though.

Trucks and School busses used significant numbers of 400's. To balance a 400 just bolt on a flywheel made for a 400! Special cranks?

Like HI^C I'm hovering in the ~400 HP range and think it's just about perfect (ok ... could use a little more ) ... and realize ahead of time it's no BMW. On the other hand, what's a nice drive in the country without a little oversteer.

 

[honk]

Testimony from a long time 383 Chevy owner:
Excellent 4x4 bullet. Torque like a tractor in the rocks. Hard to stall.

Downside: Low rev limit, not real happy about highway RPM's but it tolerates it.
It's not a racer if your into stop light drags in your Cruiser.

You can build them differently for revs, but then you sacrafice the beefy low end.

Cdaniel,
Do you use a heavier than stock flywheel?
I've got a '72 outside with a 350 that tossed a rod and I'm probably gonna' replace the engine using a 383 setup. To get that max tractor motor I've been thinking that a heavyweight flywheel would be the way to go but the parts places I've asked about it just look at me funny. So I'm wondering if I'm looking for something that doesn't exist.

 

[Rice]

Gm Performance Parts:

3986394 Flywheel
Outside diameter is 14" for years 1970-80. Crank Flange bolt pattern: 3.58"; clutch dia.: 11"; starter ring gear teeth: 168. For externally balanced 400ci small-block V8 only. Use with balancer P/N 6272225.

 

[Steve C]

Gm Performance Parts:

3986394 Flywheel
Outside diameter is 14" for years 1970-80. Crank Flange bolt pattern: 3.58"; clutch dia.: 11"; starter ring gear teeth: 168. For externally balanced 400ci small-block V8 only. Use with balancer P/N 6272225.

Oh, then nevermind on all that other balancing stuff.

 

[Rice]

Cdaniel,
Do you use a heavier than stock flywheel?
I've got a '72 outside with a 350 that tossed a rod and I'm probably gonna' replace the engine using a 383 setup. To get that max tractor motor I've been thinking that a heavyweight flywheel would be the way to go but the parts places I've asked about it just look at me funny. So I'm wondering if I'm looking for something that doesn't exist.

Sorry Honk, I'm not Cdaniel but I do run a 383.

You are correct that smoother low end torque will result from having more rotating inertia. Most stock flywheels were heavy in an attempt to smooth out the passenger car they were installed in. The best way to increase angular momentum is to use a larger flywheel (168 tooth) and a large harmonic dampner (8 inches). Because the larger flywheel also uses a larger pressure plate you end up with a lot of roational inertia.

Good luck,
Rice

 

[Cdaniel]

Cdaniel,
Do you use a heavier than stock flywheel?
I've got a '72 outside with a 350 that tossed a rod and I'm probably gonna' replace the engine using a 383 setup. To get that max tractor motor I've been thinking that a heavyweight flywheel would be the way to go but the parts places I've asked about it just look at me funny. So I'm wondering if I'm looking for something that doesn't exist.

My flywheel is the stock 400 one mentioned above. Stock 400 damper too.
You also need the 400 timing chain cover with a relocated timing mark.

I think the stock stuff is heavy enough. Don't know if there is any out there with added weight for a 400.

 

[dgangle]

I have used both 350's and 400's in several FJ40's. The 400 really had some grunt. It ran 210-235 deg F with a 4 core radiator, big GM clutch fan and no shroud. With the proper radiator, fan and shroud I would not have any reservations on a 400. As many others have said it did take an externally balanced flywheel. Tried the 350 flywheel and it vibrated like crazy. Young and dumb.