I have a friend that is building a 400 small block chevy.
It is a 1978 400cid bored .030

A machined and balanced stock 400 crankshaft

Keith black hypereutectic flat top pistons

6" scat rods

a competition cams cl12-212-2 cam kit with a 230 int./280 exh. duration and .480/.480 lift camshaft. and includes comp cams 812-16 lifters.

it will be feed by a edelbrock c-26 dual quad manifold with 500cfm performer carburetors.

it has Airflow research 195cc eliminator street heads, with 1.6:1 roller rockers, and chrome moly push rods.

the entire rotating assembly has been balanced at a good machine shop.

How much power should my friend expect from this engine? He is planning on taking it up to 6500 rpm and setting a rev limiter at 6500 rpm.

Also, what kind of fuel do you guys recommend? He wants to run it on 93 octane pump gas. Will this be a reliable street motor?

thanks for all of your help!

 

that cam is small jump her up a bit

 

That intake may be a bit much for a street engine, the cam is as said on the small side (lift wise) for a 400 even with the 1.6 rockers.. my oldest kid has a 406 sbc with a 750 holley and simmilar specs cam wise his engine is around 350-400 HP on a good day, you probably only have around 9:1 compression even with the smaller chamber heads so octane shouldent be an issue, but I would consider a good dual plane single quad over that c-26 you would get better low end response and it would be easier to tune, I would figure simmilar HP figures for that set up but with a weak low end it may not be a good street combo..

 

what cam would you guys recommend for this build?

 

What CC are the pistions, and what are the heads? From what I can tell you are going to be anywhere from 10.3-11:1 compression depending on the pistion volume, and head volume.

I agree, ditching the big intake for a simple dual plane, and a single carb set up would be a good idea. Ofcourse a 750 carb should be considered. As far as a cam goes, your going to need something on the large size, XE274 or XE284 or something along those lines. A big cam will help with that much compression, and keep it pump gas friendly. I dont see any reasons why you couldn't run 91+ if you keep the timing less than 36* with those aluminum heads, but thats if you are running 72+cc heads. If you dont know the CC on the pistions, post up the part number and I will look it up for you.

I dont know if I would spin the stock crank to 6500, but then again I dont know 400 cranks all that well. Im actually in here because im interested in what direction I should go with my 400 I just picked up.

 

the pistons have a +7.00cc head and a compression distance of 1.130 inches.

the heads are airflow research eliminator aluminum street heads and i think they have a 75cc combustion chamber, a 64cc exhaust port and a 195cc intake port.

 

The compression will be just fine, at 10.1-10.39:1. 91+ octane will more than likely be just fine in that motor with proper tuning.

 

can anyone straighten me out here????????? what is the difference between a sbc 350 and a sbc 400 is it just a longer stroke crank with same bore or what? i dtn care about cams but i want to know how they get more displacement out of the "same size out side dimentions" have anything to do with bore and crank and heads at all or just crank and bore or just crank or just bore etc. i am os confused cuz noone around my town knows anything about this stuff and i am looking to build a sbc 427 or 454 if i can 427 probably more reliable with a shorter strock than 454. i want crazy low end torque and crazy horse power so i need to know what block to start with and if is better to slightly stroke out a sbc 400 instead of strock out a sbc 350 a lot to gain same cubes unless a 400 sbc is just a 350 sbc stroked anyway. so i know from the threads on here shorter stroke bigger bore is better and this would be helpful to know what the difference is and also it is just or my own clarification. please help and advise at will i want to start building this soon

 

427 or 454 SBC??? Do you have any idea how much those blocks cost?! If you do a search you will find out all the info you need on 350 and 400 sbc.

If you don't know the differents something tells me you never had a car with real hp. An if you haven't I think your first engine should be a well built 350 with AFR head or something. Stock cars setup have a hard enough time trying to keep 350's in the road so if you had a 427/454 you will be broke and your car will be too! Hey if you got the cash then thats a different story!

 

A 350 has a 4" bore and a 3.48" stroke. A 400 has a 4.125" bore and a 3.75" stroke.

The 400's 3.75" is about as long a stroke as you can put in a stock block without too much hassle, and even then there are all kinds of clearance issues to worry about

A 427 uses a 4.125" bore and 4" stroke. It can be done with a stock block with extensive grinding and careful part selection.

A 454 has a 4.25" bore and can't be built from a stock block.

 

ok well what i really wanted is a 427 and i knew it had to be machined so i expected to pay for that. i dont want a built 350 i want something with more cubes. also not knowing the difference between stock block sizes and dimentions etc. is just because noone really spells it out and i am just searching for it now. also your correct about the car not having any real horsepower i own an 87gta with a 350 tpi and have done quiet a few mods to it including maf to sd conversion a t-56 install ls1 AL driveshaft etc. and i have turned all the wrenches myself and it all works great. but engine internals and what can be done from different blocks is somthing i know nothing about right now, that is why i am searching for it now and trying to get some decisive answers inwhich your post didn't give me any of the info i asked lilbowilson !!!! so thanx i already knew to build an engine of those kind of cubes is expensive so that was great advice and i know i could build a 350 and have it be fast as hell but that is not what i want since i specifically said what i wanted in my previous post. the guy who posted after you gave me more helpful info but still not a precise answer to my questions as to wether the blocks are the same just bored and stroked differently.. because what i really want to know is if you can get a 4.125 inch bore which the 400 block uses out of a stock 350 block. all i need is a yes or no just for my own info so i know what block i should get if i dont use my gm goodwrench 350 i have sitting in the shop. if you could please, i need info on helping me build what i want not what you think i should build and not to be sort of degraded for not knowing what you may think is common knowledge..

 

To answer your question about the 400 vs the 350 bore NO the 350 will not bore to a 400 size a 400
uses a siamese cylinder wall block that allows a 4.125" bore the 350 uses a 4" bore without the siamesed cylinders you simply can't bore a 350 to that size ...

 

thank you much that is all i wanted to know. and now i understand why you cant bore out a 350 block as well. that was very informative and now i know if i wanted a 427 i should 400 block to start and i cant make a 454 out of a stock 400 block. so thanx guys