Small block 400 build up...anyone running that setup?

[Irishpilot]

Hey all, I finally found a great donor truck ('75) that had a 400 small block in good condition. This engine is going in my '71 C-10, so I'm looking to get some decent power out of it. I've torn it apart and will have a machine shop look at the crank and block tomorrow. My questions are:

Is anyone running a non-stock 400 sb and what power/mods are you getting?

Are the stock heads worth porting (I'm thinking no at this point)

I'm looking for 400+ ft/lb of torque and upper 300's for hp and wondering if the following parts would get me there:
edlebrock performance intake w/750cfm carb
aftermarket heads (still undecided on which ones, any thoughts?)
Comp 282XR cam w/1.6 RRs
Long tube headers
Rebuild to 406ci with a rebuild kit

I'm really excited to build this engine as it's my first step to restoring the family truck! Thanks in advance for any/all thoughts!

[Longhorn Man]

Wow... not many service members on here posting from Korea. Did a tour there in 99 at camp casey.
i can't help you with your build up, but I know the numbers you are looking for should be easy enough to obtain.
As for heads, it's kinda hard to beat the GM vortecs, esp if you haven't bought the stuff like intake and valvetrain/covers.

[corn]

Any choice you make on heads will be an improvment over stock 400 heads. Toss them & drill steam holes in the new ones. It wont take much to make the power you are after. I used a set of camelback heads on the last 400 I did. I love those 400's...

[88JRFAN]

I Put One In My First 71. Didn't Know Much About Motors Back Then. It Had Dome Pistons, Heads Off 307( Aftermarket), Comp Cam 280, Edelbrock Performer Rpm Intake, Holley 750 Carb., Headers. Backed By 373 Posi. Ran Really Really Good. Is A Good Motor. Daren

[Irishpilot]

Longhorn man, I haven't updated my profile since getting back from the desert. I was in Korea 06-07, and I had a great time....too much soju and not enough sleep!

It seems as if all the mags are in favor of the vortech heads, but my question is are the ports designed for efficiency or for power? I'm pretty sure the stock iron vortechs are for efficiency but I think GM sells ported versions, which I need to find out more about.

Keep the suggestions coming!

[slammed1]

I had a 1970 400 I built with flat tops and double hump heads with .480 lift and .280 duration Cam with a RPM Edelbrock intake and 750 holley. Ran very strong in my 67 Impala with 4.10s and 3500 stall convertor,needed really good gas.I drilled my steam holes and with a 4 core radiator w/shroud and stock fan worked great.Put it in my 72 for a while and it was a real tire smoker.

[longorange68]

MY SBC 400, or 406 if you want to get technical...

.030 over, Eagle crank and rods, Speed Pro pistons, Comp Hydraulic cam, ported Dart Iron Eagle Platinum heads,stainless valves, Edelbrock Performer RPM dual plane intake, Quick Fuel 750 vacuum secondary carb. My guess would be somewhere around 400hp and 500tq, keeping it conservative, but I will know for sure when I dyno it at my buddies garage. My cam profile puts the peak torque near 3,000 rpm, plan on running a 5 speed manual.

Find out for sure if you have the four bolt main, or the two bolt mains. Contrary to popular belief, 4 bolt mains ARE NOT the strongest in the 400 block, goes opposite of the 350 due to lack of structural steel when the 4 bolt mains are tapped. Of course you will get the oldtimer who swears that the 400's are no good, and will probably mention the steamholes or water jackets as proof. It's BS. Look at an off the shelf Dart block, no weep holes between the cylinders, brand new they are $2100. Don't you think that they thought of that? I think that Dart would have quit making them awhile back if they kept failing. But then again, that same oldtimer will probably try to sell you the mythical 400 horse 327 also, seems like everyone has on of those if you've ever been to a show...

Sorry for the above rant, must hear that one at least once a week. Good luck to you, 400 is the way to go.

[slammed1]

Forgot to mention mine was .040 but was a 4-bolt main and never had any problems running upwards of 6800 rpm.was still running strong when I sold it.I have another 400 waiting to be tore down and have the heads off already,dont know if its 2 bolt or 4 bolt but dont care either way. I like the earlier 400's personally and my previous one and my current one are 1970 models.

[veinbar]

I would agree that it's hard to do better, and cheaper than the GM Vortec Cylinder Heads. Drill the steam holes, and make necessary cooling system mods. 400 ci, Vortecs, Dished Pistons, Edelbrock RPM Intake, 750cfm Q-Jet, Longtube Headers, Dual 2 1/4" Exhaust, and a slightly more than mild cam will do the trick. Good, proven cams that will give you the results you need;

http://store.summitracing.com/partde...2&autoview=sku

http://store.summitracing.com/partde...1&autoview=sku

Hope this was helpful,

-Jon

[special-K]

I love the stock one (as far as I know) in my`72 K/20.It`s a torguey S.O.B.

[slammed1]

I liked when I seen the stock specs for the 400s.
1970 400 265hp@4400 400lb/ft tq@2400 4.1253bore 3.7502stroke

the 400 lb/ft torque at a low 2400 rpm is nice.

[Irishpilot]

Thanks for the good info. I just took the oil pan off and it is a 2-bolt main and it looks in good condition. I'll find out the specifics and then its off to order engine parts! For a rebuild kit is there anywhere else to shop besides Jegs/Summit?

[Steelawork'n]

Very interesting thread.
My brother ran a modified Pontiac 400 in his 1/2T '72 in Kansas some years ago. He really liked the power it provided. I really don't know what the build was. He was at the drag strip every weekend with it though and held his own.

Just a thought on a two-bolt main...could a guy, instead of using bolts, run studs with a lock nut? Would be stronger than bolts and might be less likely to fail under stress.

[corn]

Id take a 2 bolt over a 4 bolt in a 400 any day...

[PanelDeland]

Mosyt engine builders i have talked to would rather have a 2 bolt block.If they think they need the extra strength in the bottom end they want to have it machined for aftermarket 4 bolt.The claim is that the aftermarket splayed outer bolts on the AM mains are stronger than the factory 4 bolt mains.
I like the 400.You can actually go with a slightly wilder cam in one because the added cubes mellow the cam some.I think the aftermarket heads are a better investment(if they fit the budget) than the vortecs since they will overall support more power and who ever has enough?

[the_goat]

I've heard good things about this company.
http://northernautoparts.com/
Have you started buying parts yet?

[71 super]

I ran one for a couple of years in my 1st 72. Used ross pistons (ultra lite series w/ 350 x rods) 461 heads machined to accept 2.05/1.62 valves .630/.630 comp cam solid roller, lightened crank (knife edged, cross drilled) victor jr intake, 750 double pumper with 850 base four corner idle etc., head studs, main studs, wav loc rod bolts, 4000 stall with tci manual valve body trans and richmond 4.56 gear and auburn posi. The thing would bump msd 7a rev limiter in a blink. The thing was punched .040 over and filled half way with block hard never and overheating problems and ran like a raped ape. dynoed @ 575 @ 6000, it was a waste in truck should have put it in chevy 2 or something light like that. The 400 is a great foundation for any high performance motor I would suggest good pistons and bottom end so you can up grade in the future if you choose. The combo you have picked out will go nice esp. with 3.73 gear in truck. Good luck with your build.

[chevy72blu]

I can vouch for nothernautoparts.com. Not a great selection, but the cheapest prices I have ever found on a few things. I've bought from them many times, no problems

[Coronas56]

My son is putting a 400 sb in a 1979 chevy malibu i believe its out of a 1979 blazer. Hes looking for hp and torque. Wondering what to do with the heads if he should get them ported or get aftermarkets????

[big_al_71]

I built my 400 small block see link below....
There is plenty of info on what was done to it....I could had built any motor I wanted but I chosed a small block 400 just because I have heard nothing but great things about it. I have not dynoed my truck yet have not had the free time to do so but I will tell you that it runs hard, sounds awesome and looks terrific...See my build thread......


http://67-72chevytrucks.com/vboard/s...=302855&page=2

[stllookn]

filled half way with block hard

Now I know two guys that have done this...I thought the technique was dead...KUDOS to you!

big AL...beautiful motor!!!!!

I have a small block 400 in my Longhorn with a mild cam and Edelbrock dual-plane. It ran warm so I changed the thermostat...LOL! The local short track guys run them all night long, WFO, with no steam holes in the heads.

[Ricks1971]

that's all I run is sbc 400's! I only use the 509 castings blocks which are 2 bolt mains. I like using 5'7 rods. The one I built for my 71 2.02 76 chamber heads and a small comp cam with a air gap manifold with a speed demon carb. It benched at about 425 hp with loads of bottom end. I think the 509 blocks are designed different than the 511 4 bolt main ones. I have never had a heating problem with one.

[watahyahknow]

grumpy jenkins has writen a book about it he used to run them with a steel 350 crank in it making it a 377 that reved to the moon .
yes dril the steamholes , i understood the stock cast cranks wheren't verry good

[BarryB]

Dang after reading this thread its making me think twice about getting rid of the 3 400's i have setting in the garage.

[sc340z]

had a 406 in my small tire nova dart alum heads 625 roller victor jr intake with a hp 950 carb, it was a 6 inch rod motor but the car weighed 2960 with me in it and i ran 10.50's all day with it, you cant beat a 400 with a stick