Hello, I was wondering if anyone had any input on what the best route would be to gain around 50 hp & torque on a 2 bolt main 400 sbc.

Someday, I'll swap it to an LS, but that's not an option right now, I just want some more power out of the 400 while maintaining it's drivability, it doesn't have to be the fastest thing around. An LS1 might be an option, so I'd be open to some information on that but other LS motors are not an option at the moment.

As of now, it has longtube headers, a 4bbl carburator, a TH350 built for 500hp with a 2300 stall, 3.73 rear end.

Would a cam or heads give me about 50? Or would I have to do both? Any builds are ideas are appreciated and like I said I'm looking to gain about 50 give or take, while maintaining drivability, the car will be street driving with the occasional pull, not raced or anything wild, thanks for the advice/information.

 

A good cam could get you get you close, a cam and the right intake/carb combo could possibly get you more. What do you have for an intake and carb now?
If you have stock parts look into a nice bolt on package that works well together, a cam intake and carb designed to work together will give you a real seat of the pants bump in power.
https://www.jegs.com/i/Edelbrock/350...iABEgI4CfD_BwE

 

The intake is stock, and the carb is a quadrajet. Does anyone know the stock cam specifications for the 400? As I mentioned, I will be using it for driving around and would like to keep the power in the low and mid-range.

 

The kit I posted has a torque cam that is street friendly with low to mid end grunt, the stock cam is a broomstick and the stock intake restrictive ,the Q-jet isn't a bad carb but has it limitations without extensive mods by a really good Q-jet carb guy that knows some tricks.
Edlebrock did the research on the kit I posted to match parts that work well together, it would really wake up that 400 at a reasonable cost and still be street friendly.
If you start looking at heads you're talking a lot more money and you would still need a better cam, intake and carb or it would be a waste, also the 400 is not a high compression engine so you'd probably want to do a complete rebuild with better internals ,pistons rods etc.
The good news is you have plenty of displacement to help make up for the low compression and restrictive stock heads,you already have headers so with the cam,intake, carb package it should be a real strong puller.
I've owned a couple 400 small blocks, one in a '72 Impala and another in a '78 K5 Blazer

 

Alright I'll take your word for it! I'll probably get that kit you sent, or something very similar. Thanks for the information!

 

Sure thing, ask around and look at other kits, shop around, stop in at a local speed shop or parts house I think you'll get similar info.
Get back here and let us know what you came up with and how you like it.

 

after a hiatus of 4 months i have finally ordered a cam kit. i did end up going with the Edelbrock performer kit due to price, and knowing that all things will work well together. I also ordered valve springs and retainers as the ones in the motor currently probably need to be replaced. One risk is, is there might be a different cam already in the motor, but to my knowledge there is not. The lady i bought it from knew nothing about it and sold it due to her husband passing, so ill let the forum know the results

 

New valve springs should be a given doing a new performance cam and lifter set,wise move.
Make sure you do a timing chain set too if it isn't in the kit.

 

Update: After another hiatus of the build, i finally have put it all together. Sorry about the delay in posting, been away from home with college and work.

I installed the Edelbrock kit listed above with gear drive, a cam, intake, carburetor, and the valve springs. To my knowledge, when I pulled the camshaft out that was in it, a performance cam was previously installed by the previous owner who again, knew nothing about the car.
After adjusting the timing, and fiddling with the carb, i called edelbrock because I could not get the car to stop missing under load, they suggested new metering rods #1449 which solved my missing problem. The car runs great, has good throttle response and sounds good.

Performance wise, i am very disappointed, the car seemed to have more power before i installed this edelbrock kit. Before the swap, the car would easily roast the tires from a stop just using the gas, no brakes needed whereas now, you have to use the brakes as its not even close, the midrange power also seems to be around the same or less. I'm beginning to think i got a carb that is to small for my application, which could be hindering my performance. if you think this is a big possibility, let me know! but i don't really think a higher cfm carb would help me that much as currently the car has the edelbrock 1406 carb, but again i'm learning, so let me know.

Either way, I am probably going to go a different route and get myself a nice pair of cylinder heads to try and get the performance i am looking for. Do you guys think this is a viable route? Money is always a concern, but not like it was when this post was created.

My question to the forum is, would a pair of cylinder heads with what i have already purchased increase my motors performance? or should i just get a new cam and whatever else is needed as well and sell the others to get 400+hp. the 400 HP 400TQ i believe is what i am in search of, more would be great as long as its somewhat reasonable in price.

Let me know if you have some builds you would be willing to share, your expertise is greatly appreciated. Let me know if you think i should "restart" the build and start from scratch. Thanks!

 

THIS IS A STOCK DECK BUDGET BUILD 350 oops not 400 oh well. 400 builds are at the bottom of this thing of a page for ya. enjoy reading and correcting me lol.
Measure your stock deck to pistons with a caliper's bottom end or use dial indicator on each and every cylinder starting with the 4 outer cylinders. and if it is exactly or near 9.025" and it measures close I would get your stock crank reground offset to 3.5280" for 2" bearings, and some 6" rods with 2" bearings, and some 1.261" height hypereutectic OR #2618 low expansion forged alloy pistons (non-gas port, gas ported pistons are suitable for engines with persistent numerous teardowns) bushed full floating pins. What this does is ZERO deck your block without machining the block. Get it all electronically balanced. Get it in a 4.030" overbore and you got 360 cubic inches or what ever bore you have or want to change to. 4.040" only makes it a 362 so 4.030" is the way to go this leaves you more room for future builds.
What offset grinding the crank does is allow use of decked block piston sizes. You could save hundreds or even thousands of dollars depending how good a block you have is. i'm doing this as well on this build. you can do the same with any std 1700 dollar GM crate stock replacement engine as well as they are likely down the hole O.O25". This allows the use of O.O4O" gasket. with 4cc piston and 64cc head you get a nice quench and 1O.7O:O1 static compression ratio, and with a 6" rod and a hydraulic roller XR276HR comp cam ground on a 108LSA you get an 8.7:O1 dynamic compression ratio. If you think it will hold the hp you could use an XR282HR. If you don't have decent heads I wouldn't worry about hp being too much even though the cylinders run a little rougher and have more shock, it would be down on rpm and torque with horsepower. If your crank is forged or a new cast steel crank highly inspected you shouldn't have a problem , some stock cast cranks are strong as long as there are no cracks and not misused over the years, although I would still limit piston speed to 3800 fpm if a stock. all data respectively should be checked thoroughly. And you could use the 5.7" rod with a 1.561" off the shelf piston for chevy 350 and be at zero deck instead of down the hole O.O25". Take note these pistons are made for a 'zero-decked' 9" MACHINED block, align honed the whole 10 yards. Keep in mind if your deck measures 9.020" everywhere or at 4 corners, Use the O.O45" gasket, And if your pistons stick up O.OO5" out the top of block use a O.O45" head gasket. etc. And if O.O15" out top, use O.O55" head gasket and so on. THIS is for an undecked block. now if you HAVE a decked block , your all set just swap out pistons to some good hypereutectic or the 2618 and other low expansion alloy forgings. you really need pistons that are NOT cast , because at 400 hp or more the heat is too much for a cast piston and it would become a crap engine with blue smoke and smoking puff out the exhaust sooner than later because all the heat in the top ringland and the valves and seals because of a cast piston being too hot., oil turning bad, fouling plugs ever so often, overheating etc., , etc. well here you go. I personally would get AFR 180 competition cut special ordered from AFR. and from there in price I would get AFR 195, OR PRO MAXX MAXX SERIES 183cc heads my favorite for performance , price and HIGH QUALITY,,,,,,,
, OR IRON offerings: not recommended. Vortec heads. OR DART platinum and SHP heads,, RHS, and last but not least World Sportsman II heads. These are the best qualty heads that come close to performing what is called for.. OH yes and do not forget Trick Flow Twisted Wedge aluminum heads for chevy these are great performers also. Pistons Now there is a simpler way to get around the decking issue, a custom piston, if you notice there is an off the shelf ford piston with the correct size but they only list the ford pin because of chevy owners buying that piston for their 350s, and the chevy pin shall be in their listings for other pistons for ford . you could talk to someone that shall reluctantly give you the part number for the piston meant for a ford with a chevy pin diameter with the correct piston height although they might or may not speak of it, then again they might, or they may just be looking in the same catalog as you and say things like " I am not finding it anywhere , I wonder why? . . . .. the others 'listed' have the chevy O.927" pin and the O.918" ford pin also, hhmmmm.". well hope this helps. the piston size with the compression height being 1.585" for a 5.7" rod respectively and the 1.285" for the 6" rod. Here is the example maths: Radius 1.764" (the 3.528" offset ground stroke) …….
,..,., .,...1.764" .,.,. .1.764"
ROD …6" + or rod .5.7" +
Piston .1.261" …….1.561"
…...= ..9.O25".. = .,.9.O25"
and for custom piston for undecked block and unground crank= 1.285" piston height with 6" rod ……. 1.585" piston with 5.7" rod with unground crank stock deck untouched block. remember check your bore size with a caliper to see what your bore size actually is, someone could have bored it before you and or decked the block as well..
If there isn't a machine shop up to the crank grinding , just go the custom piston route. however you shall want and need to bush your rods or get bushed rods because it costs less to get some forged rods anyway that's why I mentioned stepping straight up to the 6" rods. You can also use 5.85" rods with 1.411" pistons on the offset ground crank/ stock deck and 1.435" piston on 5.85" rods and stock unground crank with stock deck. respectively all of course. You may find this piston listed as 1.433" in that a O.O38" gasket may be used or a O.O37" although go no further decreasing in height without a quality forged crank that doesn't move at all (little movement) and even then the difference is T-T. a =O.O4O" is the perfect quench distance from piston to head. to support 400hp without porting you need a performer RPM intake and you should port match to some AFR heads or MAXX series heads. edelbrock heads are high quality and can take porting but out of the box they are just not performance enough. the difference being do you want 370hp or a true 400+ hp for street performance, this is harder to do than some may think, today we can build a 400+ hp street engine that lives and wears same as stock engine. You can change bearings and rings more often and keep it going millions of miles. just don't wait until 100 or 200k to change rings and bearings. sorry for any errors please anyone correct me where you find a flaw, sometimes I get to typing fast without thinking as straight because when I was attacked in helen ross mc nabb centers I have been disabled since, jobless, and the camaro on hiatus.

For the stock deck 4OO though. 1.875" radius (3.75" crank) 5.85" rods and 1.3" piston . to use the 1.275" off shelf piston you need offset ground crank to 3.8" stroke with 2" bearings and 5.85" rods.and 1.900" offset grind crank radius 5.85" rods and 1.275" compression height piston with O.O4O" head gasket for quench distance and stock 9.O25" stock deck..

There is also the case for a 3.828" offset ground crank, + O.O78" from a 3.75" crank in a 350 block making a 391 cubic inch 350, this is 1.914" Radius, 5.85" Rod, 1.261" Piston. for a 9.O25" stock deck height block. the reason being you want this engine instead of say a 396, 383 or others in a 350 is the piston height and is the perfect compression height for a street piston without gas ports. This 1.261" piston is the 350, 6" rod piston. with a 4.155" bore version of the piston and the offset grind with stock deck of 9.O25" you get a 415" street burner small block. With a bore of 4.185" you get a 421, and a Motown block size of 4.250" bore you get a 434 with a street piston, this is as good as it gets and its awesome.