Jump to content
HybridZ

400 SBC - questions


Recommended Posts

Guys, I've got too much invested in putting the 327 back together right now, but my research on how to get a reasonably-priced, reliable, streetable 400+hp out of a carbed SBC makes me think it'd be alot easier with cubes. icon_wink.gif

 

Anyway, I was thinking of upgrading to a 383, but today at a car show at work (no kidding!) I met a guy that has a few 400 blocks and cranks. He'll sell me one of the 4 bolt blocks that is standard bore and a crank in good shape for $125. I'm thinking jump on it.

 

I know that the 2 bolt block with splayed 4-bolt caps added is actually better for all out racing, but if I only turn it to 6000 rpm, I don't think I need it.

 

Is a stock 4 bolt 400 block up to the task of say 450 hp, along with longevity? Or is the 2 bolt block with splayed caps needed for that level?

 

My idea is to use some pink rods that I have, add ARP bolts to them and get some light forged pistons and some nice AL heads. This is all down the road a ways, but I'm thinking jump on this block and crank at this price, and since it's local, if there's something wrong with it according to the machine shop, I can work with the seller.

 

Anyway, I figure a 406 with 10:1 compression and nice AL heads (Brodix, AFR, etc.) and even a mildish cam will get me tons of low end and plenty of HP, with room to grow.

 

Should I buy this 400 block/crank, if that's my long term goal?

 

[ September 05, 2001: Message edited by: pparaska ]

Link to comment
Share on other sites

I think you'll hate yourself for not picking up that stuff for $125. Pete, this is not a bad plan and I think you know the answer to the hp question...HECK YES! Nothing wrong with going a different direction--I mean, how many times has that happened already? lol icon_wink.gif

 

You're the MAN!

 

Davy

Link to comment
Share on other sites

Pete, sorry, I never answered the question. From what I have read, 450 hp should be ok on the 4 bolt and even ok on the 2 bolt (but it's starting to push it, I think).

 

Is this all getting back to the secret lust you have for power after riding the Cobra? Hmm? Not a bad idea, really.

 

Davy

Link to comment
Share on other sites

Grab it, no doubt about it! 400s are supposedly getting harder to find and that's a fair price for the block and crank. If you decide NOT to use I have little doubt you could recoup your money. I don't think 450hp on two bolt mains would be that big a deal either - SBCs aren't that weak are they?!

Link to comment
Share on other sites

You certainly won't lose money on it. Although a 2bolt 400 is stronger than an OEM 4 bolt 400 as two of the 4 bolts on the 400 caps go into weak areas and actually promote a failure AIR. I'd jump on a 2bolt block and crank like that, 4bolt I'd likely still jump, just not leap as fast icon_wink.gif

 

You could let your machine shop know you might want to sell your 327 as you never know what buyer you might find that would appreciate the effort and $ you have into it.

Link to comment
Share on other sites

Guest Anonymous

Pete, I wouldn't hesitate to take the block and crank but the block is the real score. Aftermarket 3.75 stroke cranks are cheap and readily avaiable that are better than stck. You want to look into some 5.7" rods or longer for sure! Instead why don't you look into some long(6.0, 6.125,etc) rods to help spread your RPM range and overall torque curve of your existing 327 and add 7000plus rpm limit that can come in handy for stretching gears between short corners where a shift would be a waste of precious time. As for your 4 bolt question the blocks are good up to 450 or so, as long as compression and rev range are realistic. Now I know that I'm probably going to hear about it for sure but it just costs alot to make a 400 sbc rev to anything above 5500 reliably and actually make power upstairs. If you would like to make a torquier street setup that is more of a low reving truck styled engine go cubes, but torque in a 2500lbs. car is kind of a non issue. Small blocks just sound too good above 6000 to not want to do it often(or at least have the option). You already have the 327 so why don't you go ahead and make the revver now and make a steel crank, long rod, 220cc alum. headed 410ci motor for when the thrill of 400hp wears off and we really need to go fast!

Link to comment
Share on other sites

I'm going to see if I can shake the 2 bolt block loose from him, and forget the crank. I want to do an internally balanced 400 anyway - I can reuse balancer and flywheel that way. As for spending any more money on the 327, I think I'll leave it alone.

Link to comment
Share on other sites

Guest Anonymous

well you could always just use the 400 block with a 350 crank and go with a 377....still more cubes and will rev to 6500rpm with little to no worries.....or.....use the 327 crank and 400 block and you have a 350...just remember to drill the coolant holes in the heads that you use on the 400...

Link to comment
Share on other sites

Davy, he just needs bearing spacers to run his 327 crank with 2bolt 400 mains and he's smiling icon_smile.gif I'd do that in a wink if you can have a reasonable comp. ratio without being too far out of pocket. I've had enough backend jumping shifts in mid-rpm blasts that I have no desire to run above 6000rpm, it's plenty exciting below 6000. Maybe I'm just a wuss but I love my torque as it is and wouldn't spend dough for higher rpm band......staying lower is cheaper/safer (wuss perhaps, must be as there's far stronger hybridz out their than mine) and keeps my motor plenty happy to date.

Link to comment
Share on other sites

Hmm. 406, 377, 353, depending on what stroke to use. icon_wink.gif

 

Decisions, Decisions. Actually, the 353 (3.25" stroke, 4.155 bore) is looking enticing. I hear that the Wayne's Engines in Riverside CA (the place the supplied the stuff for the HotRod article) sells the crank,rod,bearing kit to do this. My small journal cranks won't help build this puppy - that'd take TWO thicknesses of spacers - not a good idea.

 

Hmm....

Link to comment
Share on other sites

Thanks for that info - if I decide to do the 400 crank, I may go that way.

 

Actually, I'm waffling incredibly at this point - which is fine, since I already have another motor for the car. the reason I wanted the 400 block was for cubes. I have a feeling that a high-ish compression (10.5:1) 400 with light pistons and 5.7" or 6.0" rods may be able to make decent power up to 6000 rpm. The added stroke does a bunch of things for you. The increased lever arm adds torque, obviously, but the breathing aspects are better for hiding a bigger cam as well. The intake valve closing point for a decent IMEP can be farther up the cylinder, allowing more breathing, etc.

 

I think if 6000 rpm is my goal for a shift rpm (~5500 rpm power peak), then the 400 opens alot of streetable possibilities.

 

As usual, I'm all ears. Theories, experiences, etc. appreciated!

Link to comment
Share on other sites

How about 550HP @ 6000RPM?

 

From AFR's web site...

 

RPM Torque H.P. Dyno Test Criteria

2500 463 220 Horsepower: 550 HP 406 Street Engine

3000 468 267 Engine: 406ci

3500 457 304 Heads: AFR CNC Cyl. Heads 210cc Race Ready

4000 465 354 Compression: 10.3

4500 534 457 Carburetor: 750 Carb

5000 540 514 Ignition: MSD HEI Billet Distributor 36° Timing

5500 510 534 Cam: Lunati Hyd. Roller Cams 232°/242°

6000 483 551 0560-.570 lift W/ 1.6 Rockers

Exhaust: 1 3/4" Headers

Fuel: 93 Octane Pump Gas

Link to comment
Share on other sites

How about 550HP @ 6000RPM?

 

From AFR's web site...

 

RPM Torque H.P. Dyno Test Criteria

2500 463 220 Horsepower: 550 HP 406 Street Engine

3000 468 267 Engine: 406ci

3500 457 304 Heads: AFR CNC Cyl. Heads 210cc Race Ready

4000 465 354 Compression: 10.3

4500 534 457 Carburetor: 750 Carb

5000 540 514 Ignition: MSD HEI Billet Distributor 36° Timing

5500 510 534 Cam: Lunati Hyd. Roller Cams 232°/242°

6000 483 551 0560-.570 lift W/ 1.6 Rockers

Exhaust: 1 3/4" Headers

Fuel: 93 Octane Pump Gas

Link to comment
Share on other sites

Guest Anonymous

just remember too that you can use a 307 crank...they all had large journal....now im starting to think about building another engine...great thanks alot guys...lol

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...