so these heads came of a early 90s 305 or is that incorrect? this is my first time doing anything of this nature just want it all to go good i did get the pistons and all the other little stuff cleaned yesterday got to get some more money before i get the block worked on. i was going to go a head and put new seals in the heads while i was waiting

More than likely they came off of a LO5 350 TBI.

I just purchased a junk camaro for parts that has a 406 supposedly rebuilt. Havent heard it run wiring is all screwed up. So I'm pulling it anyway and will run it on engine stand once out. Question I have is what kind of daily driver would this make? Would it be even worse than my 350 I just built for one of my camaro's as far as gas mileage? I understand that you gotta give up mileage to get power. No matter how easy I drive my 350 I cant get better than 12mpg and was just wondering if 406 would be even worse? The motor is just an added bonus. I bought car for interior, windshield and other misc that I need for my other 2 camaro's. Already have another 350 I was going to build for 2nd one but am considering tearing the 406 down to check it out and possibly go with it. So guess what I'm askin is there much difference as far as a daily driver?

well my block is at the machine shop getting everything done to it that needs to be done to it. i figured out that i need some new heads. the ones i have are to small i was told with the small cambers and small valves they will cause spark knock

Supposedly 72 and earlier had 3 freeze plugs. The only one I've ever owned came out of a 73 and the numbers said it was made in 73 and it had all three.

Oops, I forgot to mention that three freeze plugs means the block is a 72 and earlier 4 bolt main 400. I'm pretty sure the two bolt mains had two freeze plugs. This hole experience is a time warp for me. Sorry it's been 20 years since I've messed with this stuff.

well still haven't got the block back. it should be done this week. i was working on getting a list of all the parts im going to need. i am goimg to run a high volume oil pump and was wondering if the stock 4 quart pan will be alright or if i need to run a bigger pan and also with the multipiece oil pan gasket be alright with the high volume oil pump

I had a high volume oil pump, if I were you I'd forget it. Oil pressure goes up exponentially with the speed of the motor. The extra volume is merely pushing past the regulator. Because the high volume pump has the taller gears I think it's 1.3 instead of 1.0 inches.

In order to get the same pressure it (the pump) will load the cam/distributor gear by an additional 30% AT THE OLD OIL PRESSURE since this pump pumps 30% more it will yield 60% more pressure between the two (30% + 60%) you'll double the load on the distributor/cam gear (provided your using a distributor). I ran a 60lb spring and managed to gaul the gear on the cam. This never would have happened with the old pump. Pre 70's motors generally ran 60lb springs in stock form.

The only thing you will change is wether you hit max oil pressure right off an idle or at 2 or 3 grand.

well we have to bore out the block to 40 over and get new pistons. i'm goin to get them from summit and get some 5.7 rods for it. the machine shop is only charging 230 for borin it, dippin it, and new freeze plugs and cam bearings.

this is the first motor i have built and i am still kinda new at this stuff what does putting in longer rods do for the motor and what cubes will this put me at

Longer rods reduce the angle of the rod to the cylinder bore, change the "dwell" of the piston at TDC/BDC, and things of that nature. To compensate for longer rods, you need pistons with the wrist pin closer to the crown of the piston (i.e., order pistons for the rod length you'll be using).

I'm not a big fan of the short 400 stock rods, but they do solve a few problems without causing too many.

Displacement is bore diameter squared, divided by 4, times pi, times the stroke, times the number of cylinders. (4.165"^2)/4 * 3.14159 * 3.75" * 8. Punch that into your calculator, should come up with 408.7 cubic inches.

so is it really worth the $200 for the longer rods i have to buy new pistons anyways

Yes , it will be much torquier on the start with some 5.7 or 6.0 rods ...

I don't know that I'd say it would be "much" torquier.

If you decide to use different heads on your 400 remember they need to have steam holes drilled into them.

I've also heard that 2 bolt 400 blocks are stronger than 4 bolt blocks. something about the design and the webbing in the block. They don't take lots of RPM well.

well i talked to my machinest and he said that you didn't really need the steam holes and that if you buy a good gasket it won't even have the holes in it i am going to run some 883s for the time being till i can afford some good aftermarket heads this is just to get in and runnin i can get these heads for $150 they already have screw in rocker arm studs and some other little stuff done to them

Don't believe him. The steam holes may not be necessary for a track car, but a street driven car should have them. The head gaskets you use should be 400 gaskets, and they will have the steam holes unless you purposely get something without them.

i was told that the 5.7 rods need to be notched just allittle to make sure they don't hit the cam has anyone ever heard of this

Depends on the rods.

The rod itself isn't usually the problem. It's usually the bolt head.

If you buy the right rods, then no.

If you try to use stock 305/350 rods, then yes, you will have interference EVERYWHERE.

I AVOID grinding on rods whenever possible. I would go so far as to say that I won't build a motor where I have to do that, unless the customer signs off on understanding the risks of destroying the rods, rendering them valueless, etc.

I WILL NOT grind on the hardware, period.

You can also get cams ground on a small base circle, to give some additional clearance. That, and grinding on the block, are FAR PREFERABLE methods of obtaining clearance, than hacking on the rods.

Anyways summit sells some good sets of 5.7 or 6.0 rods pre-balanced and made especially for a 406 small block chevy , and they're not so expensive ... You also need a matching set of pistons though ...

will part number SCA-25700 from summit work and not have to be ground on

Maybe. The only way to know for sure is to test fit everything when you're assembling the engine.

Should. Those are floating pin, though.

whats better floating or press fit

well no suggestions

I would go floating pin if you have the choice. The floating pins reduce pressure on the small end of the rod...a little :shrug: but in the end every bit helps.

I know the Eagle 5.7" SIR rods fit mine, but it still takes some clearancing in the block to make them fit. And a small base circle cam.

i have got all the internal parts ordered and should be here tomorrow or wed. the only other internal part i need is cam and lifters should start assemblying later this week

has anyone used the summit brand intakes? wondering how they performed

well the motor is put together. the only other things it needs is a hei and carb the old motor is out. hopefully be able to put it in the car in the next couple of days

this is what it looks like now

does anyone know how many wires go to the starter?

Two, power from the battery and the ignition switch wire.

Maybe I missed it...what cam did you end up with? What exhaust are you going to use?

Don't forget the chassis power wires that go with the battery cable.

i went with a lunatti cam 292 duration and 480 lift. i got heddman headers with 1 5/8 primarys and 3" collectors. as far as the rest of the exhaust i haven't figured out yet. i thought about making my own y-pipe and maybe the rest also i have a pipe bender and getting a mig welder here soon. the motor is in the car but doesn't have everything on it yet the mini starter just came in yesterday

i have a 511 block, yes it is a 4-bolt, but some people say 2-bolt is better i dont think so, 511 are the earlier blocks, my a 1971 out of a k3500 truck, but i went 0.060 over so now its a 413, eagle rods/pistons, steel crank, the only problem with these blocks are they tend to overheat, to fix that internally, have steam holes drilled in the heads for passage ways for the coolant

these blocks are very hard to find personally, if u get a deal on one get it

i just bought a 406, (along with a 90% solid '71 nova)
the motor is a 2 bolt main, has a scat cast crank, reconditioned 5.7 rods with ARP bolts, KB hyperuetectic flat top pistons, a Doug Herbert solid flat tappet cam small base circle w/ 252*/260* @.050, and .543"/.563" lift, AFR Eliminator 195cc heads (292-296cfm) Edelbrock Vic. Jr., Holley 750DP,
stepped 1 3/4 to 1 7/8 headers

any idea what this will make for power, im hoping for at least 475 having such a decent head, eventually id change the cam to a solid roller...


the rest of the car is a 8.5" 10 bolt w/ 4.10s, TH350, Art Carr 3,500rpm stall
Weld "big & littles", M/T slicks, moroso skinnies, race seats.....

the registration says it weighs 3084 lbs, w/ the heads, wheels, race seats etc. its gotta be like 2900lbs,
i was hoping to break into the 11's at all, but some ppl are saying this could be an 11.50 car...??
what do you think?