Im buying a 400 SBC, question about combo & what heads to use.

[bipolar]

Yep, I'm buying a running 400-4 barrel small block from a 1978 C20 for $250... Its all complete & stock and has never been rebuilt/bored. Although its running I plan on doing a complete budget yet some what "HiPo" rebuild. I know... That's an oxymoron. Any way, I will most likely bore it 30 over unless its in extreme good condition but I plan on it needing it.. I think 30 over makes it a 406cid.. I really don't know much about 400's but im learning. I know they have steam holes in the heads, they are a Siamese bore block, which I hear makes it more ridged but harder to cool, & they have a short 5.560 rod. I plan on going with 5.7" or maybe 6.0" H beams & a set of Speed Pro forged pistons. Which length rod is better & why? Now here is the question I really wanted to ask...I can get the steam holes drilled locally for $20 in what ever heads I plan on using, so should I go with a set of Vortec's OR.... Aerohead Racing (AKA Indy Cylinder Heads) has a set of 1986 & Earlier, 65 or 76cc Combustion Chambered heads, with 2.02X1.60 Stainless Valves, & .525 Lift Springs, 3/8 Screw in Studs assembled and ready to bolt on for $369.00 with no core charge!! And for $150 more I can have the intake & exhaust bowls ported and polished.. Isn't the bowl area the hardest & most important part to do? I mean, I can do the runners, chambers, & gasket matching myself.. But I don't know which would be the better move. I read today that the Vortecs out flow the Edelbrock Performer RPM's at .500 lift! WoW! Maybe I should get a set of Vortecs and have 2.02/1.60 valves put in them and have'em ported and polished, but remember, this is supposed to be a "budget" build. Whenever I figure out which heads i'm going to use then I will have Comp Cams recomend a cam for my aplacation. So how do I know what heads will be best for me? Is this 400 SBC a good move or not? Any info or suggestions on the whole mess will much be appreciated wether its good or bad news.. BTW this is going into a 86 RX7 with a T56...Thanks guys!
PS... I know the Vortec's use a specific intake manifold but I have one from Professional Products that is a dual bolt pattern for either style head. I also will be using a Holley 750 double pumper with a aftermarket smooth, racing, main body.

[gravygraber59]

What type of driving are you planning on and is it a four or two bolt main block? First the block- two bolt have thicker main webbing, so can take a bit more stress but are limited on rpm to about 5500 - 6000 with bolts. Main studs do help. Next Rods - I prefer a 6 - inch rod and here is why. Even with the siamessed cylinders the out side or thrust side is thin. The longer rod gives it a better angle and more upward push. This takes a lot of the stress off that cylinder wall. Now heads - if this is going to be street driven the vortec very well and have the steam holes drilled. The 2.02 valves are good to. The bowl work will help the most and just gasket match intake and ex. The vortec will work well to around 5500 maybe 6000 and that keeps with the limit on the block. Remember one thing, the heads will dictate the horse power and rpm the motor will make. Much more than that and you need to go with splayed main caps. My combo is a stock 400 block, 6-inch rods, 12.5 to 1 compression, roller cam, raised runner 23 degree heads, and a single 1050. Good for 750 HP on the dyno. Good luck.:drivin:

[toneloc60]

You're going to love the way the 400 performs. It's truly a great engine. A lot of people have mixed feelings about them. But, in my experience, they are torque monsters! I love them.

Now, I don't know much about the Vortech heads, but I do have a set of Edelbrock Performer RPM 70cc angeled plug heads. They flow great out of the box. But they really liven up when worked. Truly a great flowing head. Plus, the aluminum's added ability to disipate heat make them a great choice for the 400 block.

Do yourself a favor when you do get it done, use an electric water pump, a good radiator and water wetter in your coolant. Do whatever you can to keep her cool.

Use the 6-inch rods. Two bolt mains are the only way to go. Splayed caps really make them tough.

Have fun and good luck.

[Mr. CarelessAndImprudent]

I hear they like to get hot, so make sure you can keep her cool.

[t/as&dds]

Like you, I don't know a ton about the engineering and details of the 400. What I can speak to is that I bought a set of 350 heads from Aerohead and they were top quality! I had them give it a 3 angle valve job and they did some porting and polishing. The things looked awesome!! The only gripe I had with the heads is that they used cheap, umbrella style valve stem seals and I eventually replaced all of them, one by one, as they kept disintegrating. Now, this is about 7 or 8 years ago and I wouldn't hesitate to buy them again. This time, I'd replace the valve stem seals before I put them on the engine and in the car.

[thepollock]

the 400 is a good way to go. the 400 i had never got hot and i beat the hell out of it. i would go a 6" rod. and hope its a 2 bolt main and not a 4 bolt main there weaker. and you can get about 7000 to 7200 rpms out of it. i did. i would go with the edlbrock heads # edl-60719 there great out of the box. well have fun youll love it.

[icemanfour662005]

i have never heard of a 2 bolt main being more powerful than a 4 bolt...all performance engines are 4 bolt out the box.. and those who have 2 bolts get them machined to 4 bolts.. i deffinately think 4 bolts handle way more power than 2 bolts

[thepollock]

the 2 bolt main is stronger then a 4 because 2ed set of bolts show more the say a 350 u really cant see ne of the 2ed set of bolts. on a 400 it has a .125 bigger bore so with the bigger bore you can see about 3/4 of the bolts and haveing a 4 bolt main weakens the webbing for the crank. this is only on a stock block. im most cases yes a 4 bolt main is stronger.