I don't know.... Maybe some pickups came with the 400 sbc... I know I had one in my old '72 Caprice Cl***ic.... What a boat that was!!!
If you build a 400 with 5.7 rods (I like 'em) be sure to clearance the rod bolts for cam clearance or go with a small base circle cam, made for this combination. I guess some aftermarket rods would work too. Just something else to check. Larry T
I went with aftermarket 5.7" forged rods. I wonder, is a 6.0" conn. rod not suitable for a street motor? (not torn down periodically) Being that the wrist pin gets into the ring guide further.
Gm may know best but they only made these engines in low horsepower 2barrell cast crank engines.All the 4bolt 511 blocks ive had were traded to bulk rebuilder because at least one main web had cracks.If your not going to plug the steam holes Make sure gm drilled all the cooling holes in the deck of your block by placing head gasket on and checking and check how many deck holes have cracks that can grow and spread to top of cylinders.Also check the main web oiling holes coming from cam journals they are commonly tapered down,i run a long drillbit through them before using.Gm makes a 400 bowtie block for perfomance use and they addressed alot of the issues 1 being avoiding the steam holes that cause cracks in the thin decks. Head studs are a very good idea on the factory 400 block or at least longer head bolts.I love 400's but i change alot of things from what came stock,all get 6" rods can use narrowed olds rods in a pinch, internally balance em with aftermaket crank to keep the mains alive.plug coolant byp*** hole on p***enger deck side (dangerously close to .030 over cylinder) to keep headgasket sealed and cracks from forming etc,etc.
400s were originally built as torque engines for pickups and other heavy vehicles. Being externally balanced, one needs to be conservative on max. RPM. Internal balancing costs extra, but that and a set of 6" rods will increase survivability at higher RPM. I raced one for a few years. They don't have any excessive tendency to overheat--but--when they do overheart, the chance of a cracked block is higher than with a 350. Mine had Brodix heads, 14-1 compression and made 625 hp on 110 octane. I turned it 7,200 rpm every p*** and never had a problem. Stout parts, good heads and the max compression you can run for your application will perform.
I guess "luck" is a combination of parts and expectations. You've got a pretty much stock lower with too much carb and intake. At as many have suggested, not all 406s are alike. For the street a 5.7 " rod will give you a much better performance than a short rod and keep the wrist pin out of the oil ring. For racing, use the 6" rod. The wrist pin will be up into the oil ring groove, but at short bursts at a time your not looking for a high mile engine. And for a street engine you might actually be better off with the larger 76cc heads. I've had a few internally balanced, 5.7" rod engines and , yes, I think my luck has been OK.
I was going to say the same thing. If you have the steam holes drilled or they already exist and your cooling system is up to par you are golden. I am by no means the world's reknowned expert but I have heard you shouldn't go past +.030. That is just what I have heard. I know that around here the roundy round guys have pretty much used up all the 400 blocks. The 377 was real popular with those guys. Properly built they would hold together and rev to beat the band. I have run a stock 400 in a pickup and it did well, and built one 377 that was scary fast. Neither had any real problems. The 377 didn't like the stock rockers but a set of Crane rollers cured that.
Back in my IMCA modified days, the 400 SBC was the engine to run. We always plugged the steam holes to prevent cracks from developing from the steam hole to the adjacent head bolt hole. A couple of these 400 blocks were sold to buddies that have street cars, and neither of them have had problems with overheating on the street. My understanding is that Chevy installed the steam holes for vehicles that would idle for large amounts of time, like Police cars or Taxi cabs, something that Hot Rods rarely do.
G'day, The 400 cid small block was originally available as a two barrel version in full size Chevies. The first two years were all 511 casting 4 bolts but in mid 1972 they started putting two bolt caps on the 511 blocks even though the blocks were drilled for 4 bolt. In 73 they went to the 509 casting 2 bolt block still with two barrel. Starting in 74, they started dropping the 400's into Monte Carlos and Malibus, some with quadrajets. In 1975, they started using the 400's in the light duty trucks up to 1 ton. These were all 4 barrel versions. In late 77 they dropped the 509 casting for a better 817 casting. Some of these 817 castings had the same percentage of tin and nickel as the bow tie blocks that came along later. A lot of people believe the 817 was the best version of the 400 because of the metalurgy involved. I have weight multiple versions of the 400 and found that one certain year of 817 casting actually weighs about 5 pounds more than the other castings. These were the best blocks to go with. The last year that Chevy used the 400 in production vehicles was 1980 in the trucks. For street use I have found that leaving the steam holes in the block and drilling the corresponding holes in the heads is the best way of making a 400 live. The 400 based engine we are putting together for my g***er is a .020 over 817 that has been converted to splayed main caps. We are running a Callies 3.875 crank with 6 inch Oliver rods and JE pistons. For heads we are running Brodix track I's with 2.08 intake and 1.625 exhaust. It will be full rollered and approximately 600 horse. Should make the ole Chevy crank. ms
i know the 509 400 block casting was made till 80,I pulled two out of 80 4x4 chevys and they both have 79 casting numbers.I prefer the pre 76 509 casting heavy on the thrust side
Still breaking in my two bolt 406. Afr heads, solid roller, 10.75 to 1 comp ratio. Made 532 at the flywheel and still making power at 6500 rpm. So far I have no complaints, pulls hard off idle and past peak power.
Used a 509 block, pluged steam holes, ARP studded mains and heads, cemented bottom of water jackets. Flat top pistons = 110 octane, .600 lift solid roller, AFR 210 cnc heads, Eagle compe***ion rotating ***y, Super victor w/holler hp 850 Ran a cooling line to middle cylinders, 572hp on honest dyno.
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