I need some help making a crucial decision. I have a 400 block that I bought 10 years ago. I plan on having it magnafluxed and if it passes, building a 406 from it. It has 4-bolt main caps. However, I have had a few people warn me about using production 400 blocks for this application. They recommended Bill Mitchell's Motown 400. But that block is over $2000. He wants $8000 for a completed engine. Now, understand...I don't plan on racing this car. I was going to upgrade to the 5.7 rods to save on 'side load' with a nodular cast iron crank (stock stroke). AFR 220 heads, 10.2:1 compression. I'm only looking for about 380-400hp and a nice thumping camshaft. Should I pitch this block and bend over for Bill Mitchell or would it be good enough for a street car? I need some ideas. I've built engines before and know that I can build myself something decent for around $4500-$5000. Your opinions would be greatly appreciated.

Thanks everyone.

inf.....i was told to never bend over for a carrot (or an engine block). ;) Sure, those new blocks are excellent. But there's nothing wrong w/ using a block like the one you have if it checks out o.k. There are lots of people here and on the corvetteforum using them. Check some of the threads here from jethroz28. He's putting together a recipe for his 406. Your combo looks good. Those heads will rock.

i agree with n-f-s, that block is just fine for that horsepower range, no problem. although i do prefer the two bolt blocks (stock type), i have a buddy that ran a 4 bolt version w/o problems.(untill the nitrous incident, that is graemlins/sad.gif ) i'm running a 2 bolt w/ main studs, which btw, i would reccomend for yours as well, and its making in the neighborhood of 500 horse, no problems with it. my next block purchase however will likely be the motown block, just purely for it's cubic inches capability. sounds like a great combo, your only problem is going to be keeping it DOWN to 400 horse graemlins/thumbsup.gif

I'm on the bandwagon, too. I have a factory 4-bolt setup that works just fine.

Originally posted by 68rs406:I have a buddy that ran a 4 bolt version w/o problems.(until the nitrous incident, that is)I'm running a 2 bolt w/main studs, which btw, I would recommend for yours as well Didn't understand what you meant. Are you saying I should forego using my current 4-bolt block and find a 2-bolt?

oneofakind67, can I ask what size and stall speed converter you are running with your 700r4?

Thanks.

It's a 9.5" Vigilante lockup converter from Precision Industries, http://www.converter.com , and it stalls about 3500 rpm. At my 2400 cruise rpm, it slips about 200 rpm if I don't lock it up. Prior to this one I had a 2400 stall low-buck setup, and there is a world of difference.

Ahhh... A 427 ci small block (I think you can actually take them to 434). It's what I dream about. Some day my friends.... Some day it will be mine.

http://www.hotrod.com/techarticles/89518/

Here's another vote for keeping the GM block (if it checks out good). As mentioned above making 400 HP should be no problem and it should live at that level with ease. It wouldn't hurt to stud the mains.

my 406 is a 4 bolt an it has made many passes at the strip the two bolts are a little stronger on the mains i sure wouldnt forget it it will make a fine running street and strip motor. i lost a cylinder due to not having enough valve clearance shatterd the hyper piston and cly. wall sleeved the block and pored it . the motor runs 6.96to 7.20s depending on weather

Thanks for your reply's everyone.

I took some numbers off the block tonight (as promised). Wasn't sure which ones were needed. The number on the back of the block reads: 3951511.

On the deck in the front of the block I found 2 numbers. First one reads: 121131495. The second one reads: T1007CKP

I've included a link to some pictures of the block and how the numbers are represented.

Here's the link: http://mywebpages.comcast.net/arap001/

Only open the big JPG files.

Thanks again. I'll post these numbers in the 'Tag Team' section of the forums as well

Looks like this block has the nodular iron main caps as indicated by the 'N' on the caps. From what I have read these are better than the plain jane cast iron caps. Saw a guy on Ebay that had one of these blocks and was asking $500.00 for it because of the nodular caps.

BTW....I am building a 408(040 over 400) as well. Mine is the 2-bolt version with ARP main studs. Will be dropping off rotating parts with my machinist tomorrow so he can balance everything. This one will replace my tired 327 in my Z.

Tom

Originally posted by Infamous:
[QUOTE]Originally posted by 68rs406:[qb]I have a buddy that ran a 4 bolt version w/o problems.(until the nitrous incident, that is)Didn't understand what you meant. Are you saying I should forego using my current 4-bolt block and find a 2-bolt?

sorry to confuse, i just got to rambling there :rolleyes: . actually, what happened was he was making close to 500 horse on the motor, and got greedy with the 'squeeze. he ran a few weekends w/ a 200 horse shot, and with the factory crank and slightly weaker main webs in the 4 bolt, he had some main bearing issues due to bearing walk at the elevated nos horsepower levels. i believe a lot of this was also because of the factory crank. before he got nos happy, this motor ran low 11's in his chevy II, and ran fine for a good full season of hard street/track duty. nothing wrong with them at all, imo graemlins/thumbsup.gif

Check out this link www.boydracing.com (http://www.boydracing.com) for a strong running 408. However it is a two bolt with splayed caps. But the motor before this one was a 4 bolt with the stock crank and lasted 6 years on the street and weekend racing running 10.90 before finnaly breaking the crank.

Charlie Boyd
www.boydracing.com (http://www.boydracing.com)

I went to the link but didn't find anything on the engine, only a bunch of videos.

The link was just to show what can be done with a stock 400 block. If you want Specs, just ask.

Charlie Boyd
www.boydracing.com (http://www.boydracing.com)

then....what are the specs???

who cares about specs, really. this isn't bench racing. he asked about a 400 4 bolt block and gave us a horsepower figure he'd like to run at. i think everyone gave some good answers to the question, myself. you want specs on 400 blocks? my good buddy has a 406 with a stock block, splayed caps, stock crank, stock rods, and ross forged pistons, brodix track 1's, a solid roller cam (not huge, forgot specs), brodix single plane, race demon 950. it's in a nova. 4:11 8.5 rear end, street driven a ton in the summer, motor has been running for almost three years, and runs 10.70's, consistently, all motor. it really isn't that hard to do. now lets try not to turn another thread into a big pissing match so it gets closed, o.k? can't we all just get along? graemlins/beers.gif

Infamous,Please don't take this the wrong way.
I read your question very carefully...
First off,what kind of uniformed person(s) would tell you that you can't use a factory 400 block to make 380-400 HP :rolleyes: That goal is a very,very easily obtainable,and very reasonable too,with no exotic or costly parts.And,I'm confused that you mention a $8000 Bill Mitchell 400 motor when you don't plan to race and are looking for 380-400 hp.Can I have your budget of $4500-$5000 ? ;) You can build a 400 and easily get your goals for half of that.I built my 454 for $2500,and it runs a best of 13.13 in a 2.73 geared 4000# Chevelle in total street trim-and I'm not saying get a big block,a 400 small block can be built pretty stout,and are even fun in stock form with mild upgrades.I'm just mentioning my motor since a 400 can be built to perform close to the same and cost the same.Again,don't take this the wrong way-I'm just giving you a different point of view.

Originally posted by Mista 4 Speed:
Infamous,Please don't take this the wrong way.
I read your question very carefully...
First off,what kind of uniformed person(s) would tell you that you can't use a factory 400 block to make 380-400 HP :rolleyes: That goal is a very,very easily obtainable,and very reasonable too,with no exotic or costly parts.And,I'm confused that you mention a $8000 Bill Mitchell 400 motor when you don't plan to race and are looking for 380-400 hp.Can I have your budget of $4500-$5000 ? ;) You can build a 400 and easily get your goals for half of that.I built my 454 for $2500,and it runs a best of 13.13 in a 2.73 geared 4000# Chevelle in total street trim-and I'm not saying get a big block,a 400 small block can be built pretty stout,and are even fun in stock form with mild upgrades.I'm just mentioning my motor since a 400 can be built to perform close to the same and cost the same.Again,don't take this the wrong way-I'm just giving you a different point of view. Mista, I was advised by Ceralli Racing Products in New Jersey not to use the factory block. They are the ones who built the dyno motor that I'm copying from Air Flow Research. I never considered buying Bill Mitchells $8000 400 motor, I was just mentioning it to explain my case. Since I last checked in on this thread I've consulted with Impastato Racing in Chesterfield Michigan about this motor. Vince Impastato (the owner) assured me that if this is only a 'street' engine that a simple glance over of the block after a media blasting would suffice. And that it would easily handle 400+ horsepower, providing I don't race the engine competitively. I am planning to go ahead and build this engine using the factory block.

By the way...if you have a recipe for 400 horsepower on a budget of half the $5000 I mentioned, I'd love to hear it. :cool:

Believe me,it doesn't cost 5K to build a 400 small block that makes 380-400 hp.Some flat top hypertectic pistons,mild cam(220-230ish @ .050),and a pair decent heads,even factory castings with 2.02/1.60 valves will get the job done.Cast crank, and factory rods too.Theres nothing expensive about it.For 5K I could build 496 stroker big block.I'm sure theres plenty of other people that would agree with me too.