First ever build sbc400

Depending on the cc of the combustion chamber, you are going to need either dished or 4-valve relief flat tops. Two-valve flat tops would put you around 10:1 with a 76cc head. Also you want around .040 quench as I have learned to keep you out of detanation and get peak performance. Your stock rods at 5.565" length would be fine but be sure to have them checked and put new ARP bolts in them. The stock bolts are the weak point of stock 400 rods. Also unless you got the Performer RPM with the spread bore pattern, you will need an adapter to mate that Quadrajet to that manifold. I would get the Performer or the Weiand Action-Plus since it looks like you are going after torque. I would also go one step bigger on the cam (268xe). The rpm ranges companies list for cams are for 350's and the extra cubes will allow for a bigger camshaft. Also make sure your heads have the steam holes necessary for street operation on the 400. Make sure you have an adequate cooling system as the 400's do put out more heat. Machine work will be your most expensive part of your build. Don't skimp on the machine work as it will cost you more in the long run. Good luck

first engine

It sounds to me like you have done some good research on setting up your engine. I think that is the ideal cam choice. Its gutsy but not radical. About the only problem I see is in your intake choice, having opted for a standard Performer, were the choice mine. The RPM starts working at 1500 rpm, where the Performer starts out in the basement, and you probably will never if ever see over 6500 rpm out of your engine.

As a general rule, when you start getting over 230 degrees duration at .050", in engines from 350-400 CID, you are starting to get into the rpm cams vs torquers.

In my estimation, its always better to err if you make one, on going with a smaller cam, since you can always over wind it for rpm and still make power, but if you have too big a cam, theres nothing you can do to regain bottom end but to replace it.

The choice of cam you have made, is a practical choice and a good all around cam for most any type of vehicle. Go with it.

The only other thing I would recommend is not to polish the intake ports, but to leave them with a florentine finish. The reason being that polished ports on intake seem to have an adverse effect on keeping your fuel/ air mixture suspended. It all has to do with laminar air flow, and not being an engineer, I wont try to explain that.
However, on the exhaust side, polishing will not only aid in flow of the exhaust but will also help in preventing buildups of deposits in the passages, as it reduces area for them to collect onto and bond with.

i have a 406 that i've been using in a 3/4 ton van.i just made some changes to it while freshenning it up.i had used the 400 rods to begin with and they are not a good choice.go with the 6" rods if you have to buy rods and pistons yet.or at least the 5.7 rods.you can get a set of 9.4-1 speed pro hypereutectic coated pistons on ebay at racers outlet for 160.00 and a set of 5.7 or 6" eagle or scat 5140 rods good to 500 h.p. for another 189.00.your piston and head combustion chamber size combination will determine your c.r..400's will take almost as big a cam as you want but the one you mentioned along with 1.6 rockers and about 200 cc intake runner on the heads you choose along with 2.02-2.08 - 1.60 valves.400's love air and they make all your power down low where it spends most of its life on the streets lite to lite.they make more than 400 lb. ft. of torque right off the bottom and up thru 5500 rpm.you can also get a cast steel crank from eagle or scat for 189.00 also good to 500 h.p. so as someone else said build a good bottom end.i mentioned the 9.4 pistons because of the price of gas but if you can afford it you can use 11-1 no problem with a good long duration cam.it bleeds offthe extra pressure during overlap.

It makes my day to come home from work and see all the comments and suggestions its much appreciated and my dad is actually giving the computer a chance now

ok the vehicle is a 1981 El camino, th350 stock converter and it has the boaty 273 posi. Now i know most ppl will say to ditch the gear and get some lower ones but i was wondering if the torque of the 400 will overcome the gear loss. my current 305 (cam,intake,exhaust) manage to beat out my brothers '81 el camino 283 (cam,intake,carb,heads) with 4.11's but he let it auto shift and i have the ratchet but anywayssss... where was i

So i should stay away from polishing my intake ports?
Buy some ARP bolts for the rods

Now when i take the block to the machine shop i need to get it hot tanked, inspected, get new cam bearings? and frost plugs?
i may need get it bored i was thinking 30 over

now for the cam some ppl are saying its good some say i could step up.. help me here

im really appreciating this help and im really enjoying all the new stuff learning

i cant remember the head casting numbers but they are stock so im assuming there 76cc