Since I'm hung over from New years and not working on my car, I finally had some time to post on the hamb. I'm just starting to build a 400 for my 47. Wondering if anyone can shed some light on them. Any luck with them? Common problems? HP? Here are my specs. 406 (.030) 2 bolt stock block Sealed power dish pistons http://www.summitracing.com/parts/SLP-W400AP30/ ARP rod bolts stock crank, 20 20 Old Chad Herbert Solid stick .550 .530 lift cammel humps 2.02 1.60 ported and polished 567 chevy fenderwell headers world single plane intake 800 Holley DP Stock points distributor converted with pertronix Super T-10 4 speed 3.55 Posi Ford 9 inch Anyone got a HP calculator? I'm guessing around 450 hp at the flywheel.
I ran one in my 32 coupe for a couple of seasons. It was a 406, 10.2/1, World 220 cc iron heads, Comp 292 cam, Offy 2X4 manifold with 2 Edelbrock 500's. It went like stink in the 2360 lb coupe with a Muncie M21. Monster torque for a smallblock. It's presently in a buddies 40 Willys coupe. You'll be happy with yours. Just take the time to do it right.
Make sure you drill the steam holes in the heads. The 400 is a good motor and are getting hard to find. I don't have a HP calculator but I'm guessing around 350-375 I might be wrong its been know to happen. keep us posted.
Heads are already drilled. I hope to go it doesn't over heat and crack. I also have to drill 2 holes on the drives side to thread my clutch piviot ball. The block is a 78.
The 400 overheating thing is not true, they are just like any SBC,if you have enough radiator they are fine.
I built one and put it in my 72 cheyenne super several years ago. Drove it a year or two then pulled it out to replace with the original motor to the truck to sell it. Then stuck it in a 72 nova and raced it at the local drag strip for two years with no problems. Traded the drag car off so I dont know how much longer it lasted but I was real happy with it. 406, mild cam, double hump heads, single plane edelbrock, 750 holley. It was fun.
That should be a fun motor to run. That is alot like my 406 that I am going to run in my '34 truck. I have about the same cam and short block but I have the 305 4 barrel 58cc chamber heads to bump the compression. I ran this motor in my dirt race car and it was snappy and made good power.
I have run them before, I always replace main bolts with ARP studs and the extra cubic inches will "eat" cam results so I would run a cam one step hotter than I would use in a 350, i.e. comp cams 280 vs. 268 and in all my chevy engines I drill and tap intake manifolds at cyl. head end water jackets and run hose from one side to anouther (around distributor) to eliminate any air pockets that could cause hot spots. Good torque motor.
I have one in my off topic 68 camaro. An 800dp sounds preety big for that motor for street use. I have a single plane victor jr and dont really like it. It's not great for street use in the lower rpm range and want to change to a dual plane some day. If youre building it to drag race, then you might like the single plane. I dont have any cooling probs, but am running a good sized alum radiator
I'm partial to building on a block casting 509 and i generally sonic check the major thrust side before doing anything.But then again i don't drill steam holes i plug them in the block also.Ron Shaver has alot of cool things he's done with the 400's try to dig some stuff up on him on the net.
I ***embled a motor for a buddy and after 2 seasons we took it down and the thrust area at the bottom of all the cylinders was really beat up. This was with Manley forged pistons. If I was going to build another for bracket use I would go with longer rods for sure. With cast pistons and street use you should be fine.
I ran one with the stock 1970 400 heads, a mild cam,[292 duration] 750 holley on a dual plane intake and 0.030 over flat top pistons with ARP rod bolts...ran a 4 speed behind it with a pickup truck 12 inch clutch, a 3.40 low gear saginaw and 2.29 rear gears... It was easy to drive in town with a 3.40 first gear and cruised at 75 effortlessly with the high rear gear...had enough torque to cover the wide gear spacing. I ran steam holes and used a tall aftermarket new br***/copper radiator for a 55-59 chevy pickup..car was a 50 chevy sedan delivery at 3300 lbs.
The only things I'd do differently is to ditch the double-humps and the single plane intake. I'd use a set of late model Vortec castings (062, 906) and a E-brock Perf. RPM air gap intake. Be sure to use at least 1:1 pullies for the water pump, maybe even overdrive the WP a little. Those 400's can run pretty well, should be a tire burner behind that 4-gear.
Any idea what your compression is? 450 horse sounds way high to me for pump gas with that combination. I'd also x2 the comments on the 800 DP and the single plane intake for the street being overkill that will actually hinder normal driving performace, better suited for all out high rpm applications
Sold my 406 and bought the roadster body .And the guy pulled low 13's at the strip with the wrong carb......My motor was a 406 Flat tops 501 cam and shaved 10 76 cc heads and a 750 holley
You covered the important step. The recommendation to run the crossover at the rear is a good one as well. Run it and have fun.
I put a 406 in my '75 Chevy Van, Isky RV cam, drilled heads, Edelbrock intake and a Quadrajet. Did need a 4 row radiator for towing. Great engine and if I sell the Van it stays in the shop.
The guy that does my engine machining, is comfortable going .060 over on a 400. Mine is already bored .030 over, and needs to go to .040 to clean up.
Personally never ran one but i have a soft spot for 400s. They put me through college, would buy out of junk yards and supplied for a few race shops... I can ID one in about 2 seconds. haha
As already mentioned change the rods. The problem with 400's is the short rods. Use at least a 5.7 rod as all other SBC's use and you will be very glad you did. The longer rod requires a shorter piston, which is available everywhere. I build at least 10 a year and never reuse those short rods, in the trash they go.
I thought about the longer rod idea. I like the idea but I decided to go with the theory that "If GM built it, It's ment to be driven on the street for lots of miles". Thats also why I went with dish pistons
My 72 c10 ran the deep first gear saginaw behind a hot 307 with 3.08 posi. Loved it, broke first and second lose all day long. I'm putting on the big style flywheel with a borg and beck style clutch. I like your car.
Seems like a good idea. If the steam holes are there then they must have a chance of building air pockets. GM knows best.
GM rethought about the short rods too, and since the stupid guy who made them run the short rod was now unemployed they now use the longer rods in all the GM crate performance motors that use that stroke crank. Be aware the dish pistons need to be D shape dish not the ones that the same stupid guy made them run that were full dish and eliminated most of the quench pad area and cause detonation. I think the unemployed guy also designed the Vega motor
I built a few for the street i would use vortec heads, reverse dome pistons to keep compression at about 9.5 , 6" rods victor jr intake 750 cfm holley at least ARP MAIN STUDS
At one time I had in my shop two 400's that disproved the 'rules of thumb' for 400's. The two rules were [ irrc, prolly have it backwards ] - #1- 3 freeze plugs = 4 bolt mains #2- 2 freeze plugs = 2 bolt mains I had a 3 freeze plug block with 2 bolt mains and a 2 freeze plug block with 4 bolt mains.
I hear that. Back in the day I had a 3/4t 78 Chevy pu. Built a nice 406 (performer/Q-jet)for it but was a dope and used stock rods. Hauled a Big slide in camper and a 2800# bracket car in a 22' enclosed trailer. It got 3 1/2 mpg YES, had NP medium duty 5sp trans, 60mph in 4th. I believe it would have been better with 5.7 rods but will never know as I got weary of the milage real quick. Went to a crew cab single wheel w/454/T-400=6.5mpg hauling same load, all stock.
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