350 Stroked to 383 vs 400 Stroked to 421...

[Guest Mike]

Which one... which one... WHICH ONE?!?!?!?!?!?!?!?

 

 

Please list the PROS / CONS of each. Don't be shy... just hit me with all you've got.

 

OH... AND PLEASE... THIS IS LIMITED TO GEN1 SBC's ONLY.

 

I warned ya' doc. Ya' had ta' bring this up in another thread, didn't ya'?

[jnjdragracing]

Go with the 421 CU. There is no substitute for Cubic Inches. Unless you are talking about Boost.

 

I know you said only a 383 or 421 CU. But if you are building it I would go with a 434 CU.

 

Just my input......

 

John

[rytherwr]

I'm presuming we are talking about a chevy motor...if so, I'm with John...it doesn't take any more to build a 434, in fact it might be less as a 421 is kinda one off that not many folks play with

 

Wayne

[Guest Mike]

Sorry guys... showing my ignorance here:redface: Yes, this is limited to Gen1 SBC's. I updated the original post.

 

Other than potential max HP/torque. What are the PROS and CONS of each... reliability, temperament, longevity, overheating, etc.

[grumpyvette]

a few thoughts

 

most CHEVY 400 blocks are in the area of 30-35 years old and were thin wall castings, rust and age have generally not been helpful, while the slightly larger bore is a plus in unshrouding the valves,it also leaves very little head gasket seal area between the bores, and the need to use steam holes drilled in the matching cylinder heads and the slightly less efficient cooling due to no water/coolant flow between the cylinders on the 400 blocks makes them slightly less desireable for street use.

you can stroke/bore a 350 block to ABOUT a 396-401 displacement,

(.030-.060 over bore and 3.875 stroke) the 400 blocks with the same over bore and stroke will give you ABOUT A 421-426 cubic inches of displacement

yeah its true a 4.0" stroke crank can be fitted with alot of clearance work and a small base cam that the 3.875" stroke requires also, but the gains are not worth the extra work/expense in most cases.

neither the stock 400 or 350 blocks are designed for more than a .060 over bore and some won,t work with more than .040

neither stock production block is designed for more than about 400hp, yeah, we are all aware of guys running more but they are all STRESSING the block past the design limits for long term use, yes they do comonly hold up, at least for awhile simply because an engine that potentially makes 500hp at lets say 6500rpm seldom sees that rpm range on a constant basis.

aftermarket blocks are significantly stronger and thicker in the critical cylinder wall and main cap web areas.

if your going to build an engine that exceeds about 500hp the aftermarket block is the route you should sellect.

the best return on your investment (cost vs hp)is usually a 383 or 396 built on a 350 base block, yes a 400 base build generally produces slightly more power, it also generally costs more and has a higher component breakage potential.

you can build a nice dependable, ECONOMICAL 450-500hp engine from a comon 383-396 displacement, useing good heads, a decent cam and reasonable compression, if you want significantly more power BUILD A BIG BLOCK,once you exceed about 500 hp the big block starts to cost a similar amount, past about 600hp the big blocks tend to cost less per hp

yes a 383 will generally live with hp levels that far exceed the manufactures specs, at least for a limited time, but again plan your build and don,t expect stock components designed for under 5500rpm and 380hp levels to live at significantly higher stress levels

 

EXAMPLE

 

well, take notes, you want to install a 3.73-4.11 rear gear, and a 3000rpm stall converter or a manual trans

 

10.5:1 cpr 383 stroker kit,

 

http://store.summitracing.com/partdetail.asp?part=ESP%2DB12011030&N=700+115&autoview=sku

 

a set of the new AIR FLOW RESEARCH 195cc heads,

http://airflowresearch.com/195sbc_sh.php

 

if your on a tighter budget, install this cam

a crane #110921 cam,

 

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=110921&lvl=2&prt=5

 

http://store.summitracing.com/partdetail.asp?part=CRN%2D110921&N=700+115&autoview=sku

 

got a few more buck$ available? go with a killer solid roller

 

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=00425&x=19&y=6

 

rockers

http://store.summitracing.com/partdetail.asp?part=CRO%2D73600%2D16&N=700+400401+115&autoview=sku

 

 

a HOLLEY intake

http://store.summitracing.com/partdetail.asp?part=HLY%2D300%2D110&N=700+304703+115&autoview=sku

 

CARB

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRO%2D67200&N=700+115&autoview=sku

 

headers

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HOK%2D2224HKR&N=700+400390+4294908216+115&autoview=sku

 

nitrous

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=NOS%2D02001NOS&N=700+400047+115&autoview=sku

 

 

then add tires and GO KICK BUTT..youll have 500 hp BEFORE you hit the giggle gas and up to 700 on the giggle gas

 

could one of you computer literate gentelmen post a DD-2000 on that combo with the new AFR flow numbers and the rest of the specs

[Guest Mike]

Well, the bigger cubes are tempting... but you know I'm looking for something reliable. Also (as nearly as possible) a practical, reliable, set/forget design. Are the 400 based strokers really that unreliable for a street build?

 

I've considered BB's but have decided to take the easy route.

 

Okay, so a 383 as the best SBC setup to fit my needs? You mentioned a 396 too. How do the 383 and 396 compare with reference to my goals? Will a 383 or 396 stroker be more reliable than an non-stroked 400?

[grumpyvette]

a stock 400 and a 350 stroked to 383 have exactly the same stroke at 3.75" in fact the first 383s were simply 350s with a 400 crank installed in the block after a .030 bore and the 400 crank having the main journals cut down to the 350 bearing size, a 396 is just a slightly longer 3.875" stroke. personally Id build the 383 as the least expensive route to getting max power per dollar

 

look over the combo above it will get you that 400 rear wheel hp, yes it will idle rought and have less than ideal traffic manors but floor the cars throttle and youll forget all that, and hang on with a big grin

 

remember your trying to get the best results for the money spent, and have an impressive power level without going broke doing it

[dr_hunt]

Grumpy has some good points. Things to be aware of;

 

If your building a 383 and you use anything but junk 400 rods, you have cam clearance issues that require rod clearancing on 5.7 inch rods or the use of aftermarket rods already clearanced. The forged 6 inch I beam rods have the same problem. The 350 rod bolt is longer than the 400 bolt.

 

That is compounded when using a 3.875 stroke and almost a nightmare with the 4 inch stroke unless you use an ultra small base circle cam which they do make. Crower makes some rods that work well with the 434 also. If going aftermarket block, get the raised cam version and then there are no hassles.

 

Head sealing isn't a problem in 400 engines IMO if you do everything right, which is decking and using flat heads, not warped heads. I've never heard of head sealing issues unless there is some problem, like warped deck, warped heads, insufficient torque, wrong gasket, etc. NOS always blows headgaskets and so do blowers and turbo's. For your application and HP level you should be fine if everything is right IMO.

 

I don't do steam holes anymore, haven't for years, been running 400 sbc's since the late 70's on the street and strip. Personal preference I guess, but I haven't had any issues, maybe some have.

 

If your into budget the 383 is probably the way to go like grumpy says, if your going to spend more money, then go cubes, you'll never be sorry. A 383 isn't much better than a 350 unless it has good heads, if your not going to use good heads, then the 383 won't gain you much IMO. I think grumpy stresses heads as do I, they make a world of difference. Rule of thumb, build as big a motor as you can afford.

 

Why don't you have grumpy build you one, then you know it'll be right.

[jakeshoe]

personally Id build the 383 as the least expensive route to getting max power per dollar

 

remember your trying to get the best results for the money spent' date=' and have an impressive power level without going broke doing it[/quote']

 

I would agree 100% with this statement and having built quite a few 383's and a couple of 421 SBC's the 383 will be a cheaper and I believe more reliable setup.

 

You'll get into some additional machining on the 400 block if you use an OEM casting. They need deck plugs added and really need a partial fill for any significant power.

The decks crack on 400's due to the additional steam holes. Sometimes this isn't an issue but it will eventually be.

 

An aftermarket block really is the way to go for a stout stroker 400 based combo. It will probably be a wash cost wise when you really figure it up with the machining of the stock 400 block.

 

One thing I'll add is, I've used the Scat capscrew I beam rods in 3.750 stroke combos with no clearance issues, even using stock base circle cams...

One of the 421's I did had Eagle H-beams and a small base circle roller and it all cleared. So it isn't THAT bad...

[280zwitha383]

If I had to do mine over again I would build a 396 stroker. 13 extra cubes isn't going to do much for you maybe 15 hp but it should be comparable in price compared to a 383 and not many people have a 396 stroker. Atleast I've never seen one.

 

As far as I know there isn't a major price difference between the 396 and the 383 is there?

[280zwitha383]

One thing I'll add is' date=' I've used the Scat capscrew I beam rods in 3.750 stroke combos with no clearance issues, even using stock base circle cams...

One of the 421's I did had Eagle H-beams and a small base circle roller and it all cleared. So it isn't THAT bad...[/quote']

 

Are you talking about no clearance issues PERIOD or no issues with the crank?

[jakeshoe]

OH,

I'm was speaking of rod to cam clearance issues. I have heard of some people building 383's with NO grinding (on the block, etc.) but that has never been my experience.

 

The biggest issue when building a SBC stroker becomes the rod to cam clearance issue. There are a couple of offending rods that tend to contact the cam lobes. (#2 and #6 IIRC)

 

You can and usually will have to grind the block, but you cannot grind the cam lobe obviously and there is only so much material you want to take off a rod bolt to beam transition area.

 

My 400 with Eagle capscrew 5.7 rods I just had to touch up the transition areas on the two offending rods. One would clear but BARELY, so I gave it a quick grind and smoothing to knock it back .040" or so.

My cam was a slightly reduced base circle 1.050" as I remember.

[dr_hunt]

OH' date='

 

The biggest issue when building a SBC stroker becomes the rod to cam clearance issue. There are a couple of offending rods that tend to contact the cam lobes. (#2 and #6 IIRC)

 

 

[/quote']

 

 

#2 and #5 actually.

[grumpyvette]

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=119661&lvl=2&prt=5

 

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=119651&lvl=2&prt=5

 

anytime you run a roller cam on a reduced base circle its almost mandatory to use a BILLET core vs a cast core cam, because the spring pressures put a huge torsional load on the cam, notice the cam Im useing in my corvette has a .900 base circle and a billet core making clearancing the rotating assembly far easier and my friends corvette with a 454 sbc has a .(second cam) .860 base circle and a billet core making clearancing the rotating assembly far easier

[grumpyvette]

BTW I was E-MAILED asking why I seem to be advocating solid lifter cams but run a hydrolic roller in my personal car..

excellent question and I will agree it seems to be a parodox, untill you realize that I was NOT looking at costs, only max performance, and I was looking to allow the sensors on my EFI to work correctly, knock sensors on EFI systems tend to see the rythmic clicking of properly lashed solid lifters as ENGINE DETONATION or knock, and retard the ignition timing, a real p.i.t.a. . TRUST ME I TRIED SEVERAL SOLID LIFTER DESIGNS,that flaw in the EFI/CPUI could not work around easily with the CPU Id sellected when I built the current engine combo.since Ive decided on upgrading to a BBC combo on my corvette and Im in the process of finnishing my garage build further developement has been on hold temporarily , but theres no way on earth the BBC will be anything but a good solid lifter cam(roller) and IVE upgraded the EFI so I can program AROUND the need for a knock sensor, specifically because a solid lifter potentially produces better results and I know that so Ive done the necessary changes to run one, but it makes no sence to upgrade the older engine combo that works reasonably well while I put togeather the necessary components to swap to a 500 plus displacement big block with a 4L80E trans and DANA 60 rear diff

 

read

 

http://www.idavette.net/hib/camcon.htm

 

 

http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm

 

 

when COST is not a major factor a ROLLER CAM is a good idea, when COST is a major factor, a solid lifter flat tappet is almost your only realistic choice, as its a great value, in hp per dollar spent

[LS1 240Z]

if you had money id highly suggest getting an aftermarket block and making it a stroker motor. you can get aluminum aftermarket small blocks.

 

if you want cheap, and stout get a 2 bolt main 350 block and splay the mains. then stroke it.

[Guest Mike]

if you had money id highly suggest getting an aftermarket block and making it a stroker motor. you can get aluminum aftermarket small blocks.

 

if you want cheap' date=' and stout get a 2 bolt main 350 block and splay the mains. then stroke it.[/quote']

 

Thanks LS1 240Z. I've considered the aluminum blocks, but I don't thing it's worth the extra $3K or so... to me anyway. If you know of any more affordable aftermarket aluminum blocks, I'm still interested in one. Otherwise, I'll likely stick with iron. Besides, if I'm going to spend that kind of $$$, I may as well go LS6:wink:

[LS1 240Z]

LS6s are junk, so are LS1s

 

Gen IV motors are where its at.. LS2/7

[dr_hunt]

Of course that is your opinion, many people find them very desireable, usefull and dependable as I do the Gen 1 motors. Myself, I am being dragged into the technology age, you seem to be already there with the next gen sbc.

[Guest Mike]

LS6s are junk' date=' so are LS1s

 

Gen IV motors are where its at.. LS2/7[/quote']

 

I don't think I've read anything bad about these. What's wrong with them?