350 parts in a 400 block................? can it be done?

[CTFuzz]

I can pick-up a SBC/400 ci block and crank very cheap....I have lots of 350 parts in the garage. What 350 stuff can be used on the 400?? I know about the flywheel and balance.....By the way , how difficult is it to find a stick flywheel? Is the crank bored for the pilot bearing?

[Tony]

Ok, i'm tapping my memory, which isn't that good.....

You can use the 350 crank in the 400 block to make a destroked 400...
It comes to i think 377 ci..

Where i'm drawing a blank is what length rod and what pistons to use..

One of the guy's in our club has a destroked 400 with a BDS huffer in a 32 chevy....
548hp on the engine dyno..

A stick flywheel for a 350 shouldn't be all that tough to find, and i do believe (at least the ones i've done) all had the pilot bushing hole in the cranks.

Rat.

[Nimrod]

You can use the 350 crank in the 400 block but you need to use bearing spacers to make up the difference in main journal dia. Pistons are available to use that combo with the 5.7" (350) rods. You can get pistons to use the 5.7" rods with the 400 crank as well.
I was putting together a 352" sbc using a 400 block with a 307 crank, 6" rods, and some off the shelf stock car "claimer" pistons.

[Unkl Ian]

Nimrod is correct,the main bearing diameter is bigger on the 400 block,
but special thicker bearings should still be available.

This swap used to require making special spacers,
but there was enough demand that special bearings became available commercially.

If I was building a street motor,especially with a heavy car,I would use the 400 crank.No question.
Never mind all the complex engine theory.Bigger IS better. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif
The only substitute for cubic inches,is cubic dollars.


And you can still tell people it's a 283. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[k9racer]

If using other than 400 heads be sure to drill steam holes in the head. Also use 400 head gaskets big bore plus they have steam holes and use them as a guide to drill.The 400 also uses a larger oil pump millings no. M77A. I have run this combo before on round track but on the street I would rather have the longer stroke 400 crank with stock rods Good Luck I hope this helps.

[CTFuzz]

Thanks for the info guys.........I plan on using the 400 crank with 350 rods and get what ever piston needed. Question is, because of the externial balancing, can I use the 350 flywheel? And yes, I will tell everyone it is a 283 http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif Actually I have offset Corvette valve covers with mods to the heads to mount the valve covers and an early 3 carb intake for early Ford carbs,94'S........

[Nimrod]

Don't think you can use the 350 flywheel. The 400's use both an unballanced harmonic damper and flywheel. You should be able to find a 400 flywheel, I'm sure at least some trucks used a 400 with a manual, or you can find one in the aftermarket.

[thirtytwo]

i think scat makes a crank with larger journals, so no spacers are needed , i believe a 454 and a 400 flywheel are interchangeable but DONT quote me on that look in any roundy round catolog and they will have the parts ....

i saw some claimer pistons for around 250 for this app. some where i was thinking of building this combo also.im not sure what to think of the bearing spacers but if i remember right the scat crank i mentioned was around 250 bux you get a cast steel crank and bigger journals to boot

i think i saw this stuff in the speedway race catolog??

[k9racer]

Speedway motors sells a ballance plate that goes between the crank flange and the flywheel so you can use a 350 flywheel on a 400 crank for sticks. If you are running a automatic you can buy a external balanced flex plate chaep at most parts houses. You must use a Harmonic ballancer for the 400 crank.On the street I like the short 5.5 rods more bottom end pull and less rod angle plus you dont have to grind the block or rods. You might have a clearance problem between the rods and the camshaft with the 5.7 rod.I have a friend who uses the stock 400 pistons on 5.7 rods. He uses the dish piston and cuts down the top of the piston to get 10 thousands deck clearance. this also moves the rings closer to the top of the bore for better seal. I hope this helps some more.

[FWilliams]

use the correct balancer/flywheel for whatever crank you use
350 internal balance
400 external balance
doesnt matter what the block is, go by the crank


400 uses the same oil pump as any other SBC
the mellings hv 77 is a big block chevy pump and not needed for your application. the mellings hv 55 would be more than enough pump for your application

[dutchtreat]

The 350 crank fits into the block using a special set of spacer bearing.Then you use the 350 rods with custom TRW pistons to get a 377. You use 350 bal. and flywheel with the 350 crank and 400 bal and flywheel with 400 crank. If you have the 400 crank you can build a long rod 400 using 350 rods-and a 400 pistons for the 5.7 350 rods. Hope this helps

[thirtytwo]

hey racefab how about your opinion on pros and cons of each assy

400 crank 350 block

350 crank 400 block

[JOECOOL]

377 , 400 block x 350 crank,used for high rpm ,definately not a torque motor. Our race 377 's run 7600 rpm. 383 ,350 block x 400 crank, are torque motors ,if built right will equal 400's torque , run at under 6000 rpm.
The 383 will have twice the torque at low rpm's than the 377, and therefore be the best street engine. We use the 400 main bearings as spacers ,just cut the tangs off.

[Model A Vette]

I believe the cheap way to build this setup is to use the 350 crank and rods with the 400 block and pistons. When used in combo with the 350 rods and crank the 400 pistons have the correct pin height. You use 350 heads to boost the compresion as the stock 400 pistons are deeply dished. You might have to go to even smaller chambers. The old TRW engine parts books listed this combo in their "Racing" section.
This is all from memory and I suffer from CRS, like other gray beards here, so check my "facts"!