Sbc 400

[TEXAS-HOTROD]

Everything Jim said is basically what I said. So how can what I said be all backwards?

The "average" mechanic doesn't realize that choosing rod length is as inportant as picking the proper cam and header size. The main considering factor on how the engine should be built, is how it will be run.
Be careful when purchasing stock 350 rods. The back sides of the rod bolts will hit 2 or 3 of the lobes on the cam, when using a 400 crank w/stock 350 rods/bolts. It depends on cam timing and lobe size, but parts will iterfere. There are special rod bolts on the market to solve that problem, or the rods can be modified and shorter bolts used. In extremely radical combos, custom small base-circle cams are needed.

There has been no talk about clearancing the block.
Reliefs are cut into the sides of the block for rod bolt clearance. You need to decide if that is something you can do or the machine shop will have to.
Oil pumps too. If you want to nit-pick, even oil pumps make a difference. The correct pump can free-up a few extra horses.
Plug the oil drain-back holes ablove the cam. Drill a small hole into the oil galley behind the cam gear to lube the thrust plate. Tap and plug the big coolant holes in the deck surface. Drill steam holes (at the needed angle) in the heads needed for the 400 block (and using the special gaskets). Plug the small coolant hole under the right side water pump port. Etc, etc,... It's more than just bolting aprts together, it's the little tricks that make the difference.

[406Elcamino]

Why are you blocking off the thermostat bypass hole? Fine for a race motor that only uses a coolant restrictor but not for a street engine with a thermostat.

[Blue Bowtie]

Originally Posted by silicon212

If you keep in mind that the 882s were a stock, smog-type head with 76cc chambers and fairly restrictive intake runners, they should be ok in the short time. There's nothing wrong with 76cc heads on a 400, as long as you have flat top pistons (if you want it to make power). 70cc '993' heads would be better if you can find them (they were stock on some older 400s). These have a better intake runner arrangement and can be made to accept 2.02 valves just fine.

Wow. I don't think I've ever read the terms "'993 heads" and "better" in the same context. "Better" is a very relative term here. If we're talking about wheel chocks or mud anchors, that might apply

That being said, I've also ported and refit 2.02/1.60s in '993 castings - Screwed studs, guide plates, bowl porting and blending - The whole nine yards. They still don't flow worth a damn, but they are certainly "better" than what they were (I think I even still have those lying around somewhere, since I'd feel bad about giving them to anyone except for the aforementioned uses). They are probably "better" than some of the other possible smog-dog castings used by The General. Still, there are probably far better choices just sitting in junk yards waiting to be unbolted. '083s come to mind first, but the tighter 64cc chambers might boost the larger bore to more compression than you might be prepared to use. BTW - The 3998993s I had started out as 75cc chambers and finished up just over 73 after fitting the larger valves (a little shallow on the seat grind for better rocker geometry).

[TEXAS-HOTROD]

Since there's so many manufacturers of aluminum heads, prices have really become affordable for the back yard builder. Wasn't this thread intended for an "average" torque engine.
I surely wouldn't waste the time and effort to mod a junk set of cast iron heads any more. It's so much easier just to bolt on a set of AFRs.

Thermostat bypass?????

[MrPbody]

Texas,

Not to stir it up, but your advice is what is backwards. And what we said is not the same. The longer the rod, the better. If that means a little more effort to make clearance, so be it. It may be easier and more convenient to use the short rod, but it will not improve the engine in necessary areas. Consider, the LAST reason to use ANY part in a performance applicatioin is ease or convenience. We don't build them for ease of maintainence when we're looking for horsepower and/or longevity.

There are several good reasons for using iron heads, too. Heat-sink is one. An iron head, in the average engine, will provide more efficient use of fuel, provided the octane required to support the compression ratio is maintained.

I'm of the opinion, if you WANT aluminum heads, go for the gusto. That is, get Darts or Edelbrocks. AFR heads are alminum, and they work. Darts and E-heads, IMO, are far superior in design and in manufacture. And yes, they do cost more... Again, you get what you pay for.

993 heads are fine for a mild build. They're VERY popular among the circle track crowd, where large chambers and stock valves/ports are required. It, along with 441, 997, 336 and 487 are good heads.

There shouldn't be any "clearancing" in a 400 block as there is in a 350 when building a "383". The rod bolt-to-cam issue does exist, as Texas has pointed out. We use Eagle H-beam rods for most of those, which are "relieved" at the top of the bolt for that purpose. When using stock rods, we simply grind off part of the rod and bolt head. I know, it sounds scary, but we've never had a problem in twenty-plus years of building some stout 400 small blocks.

Jim

[TEXAS-HOTROD]

I have never seen a clash in advice turn into an argument. Can't you just post your advice along w/the others? Making a point on who's correct or not isn't cool at all.
I know clearancing a 400 is not needed, I was confused on an earlier 383 post. Yes, a longer rod lessens the side-loading on piston and is better for a high rpm engine. Is a longer rod better? Yes and no, it depends on the application. If the car will be raced and run hard, a long rod is better. With all things being equal, it'll produce power higher in the rpm range (as I stated before and you confirmed that). A stock length rod 400 will make the power/torque sooner, yet very capable of turning safe rpms in the 5K/5500 range. Long rod/short rod, big cam/mild cam, big runners/mild runners, aluminum heads/cast heads, etc,... IT ALL DEPENDS ON WHAT IT WILL BE USED FOR.

This original thread was meant for a stock-ish torque engine for a semi-stock Chevy truck. A stock-length 400 would work great. Good power, great torque and lower rpm levels (stock axle ratio, stock converter, stock tranny???). There is nothing wrong w/an all stock 400 w/a mildly modded set of heads and a decent cam. We're not talking about building a circle track car here. It would be a whole different combo where long rods and more attention to detail is needed. This is more for pulling hills (locked up in over drive) and towing a trailer.

I too have 20+ years in building small block 400s, as well as all forms of custom fabrication, auto/manual tranny rebuilding, turbo/blower/nitrous systems, efi tuning, paint/body work,etc... So don't come off in public making out like I'm some kind of idiot. I don't need crap from peeps like you. I take time out of my day to sit here and give good honest advice to those in who ask for it.
Send me a P.M. if you want to argue.

[kress1500]

Thanks for all the advice. i've been lookin at GMPP vortec heads in summit and the price is right, so can anyone tell me how they would perform on the 400/409? its a mild street engine, not an all out racer, so edelbrocks and so on seem like overkill for me. Thanks a lot,
Tommy

[TEXAS-HOTROD]

You need to call Summit's tech department and verify 2 things.
Make sure they are compatable on a sb400. A 400 head gasket seals a bigger bore than a 350, you need to make sure that there aren't any water jackets that will interfere w/gasket sealing.
The heads will have to be drilled for steam holes. Ask if these castings will allow for them.

[jveik]

i bet the comp cams xtreme energy 274 cam would kick serious ass in this combo, especially if you dont want to rev it over 5500 or 6000

[kress1500]

Summit says that the heads can be drilled for steam holes, but can anyone tell me how well the vortec design will work with the 400/409? im not lookin for much over .475 lift. thanks, Tommy

[silicon212]

Originally Posted by Blue Bowtie

Wow. I don't think I've ever read the terms "'993 heads" and "better" in the same context. "Better" is a very relative term here. If we're talking about wheel chocks or mud anchors, that might apply

That being said, I've also ported and refit 2.02/1.60s in '993 castings - Screwed studs, guide plates, bowl porting and blending - The whole nine yards. They still don't flow worth a damn, but they are certainly "better" than what they were (I think I even still have those lying around somewhere, since I'd feel bad about giving them to anyone except for the aforementioned uses). They are probably "better" than some of the other possible smog-dog castings used by The General. Still, there are probably far better choices just sitting in junk yards waiting to be unbolted. '083s come to mind first, but the tighter 64cc chambers might boost the larger bore to more compression than you might be prepared to use. BTW - The 3998993s I had started out as 75cc chambers and finished up just over 73 after fitting the larger valves (a little shallow on the seat grind for better rocker geometry).

Never mind ... the heads I had were 3973493 not 993 ... I stand corrected!

It's been 18 years since i had them. They were off of a 1971 400.

[TEXAS-HOTROD]

I have a Comp Cams 292H in my Biscayne's 406. It has an impressive idle, yet not too rough.
Beware that most stock 400 heads (I don't know the casting #s) are prone to cracking.

[kress1500]

Thanks for all the advice. i really appreciate it. i've got the 400 sittin in the garage, but im going to have to hold off for a while because i've got to pay for school and so on. after im done with school i'll have a lot more money to play with, and i can afford some decent stuff.
Thanks a lot, Tommy

[TEXAS-HOTROD]

Good luck in school.
Post an update when you get back on the wrenching.

[kress1500]

Does anyone have any experience with the Holley systemax II kit? (heads, intake, cam, timing set, bolts, and so on) it looks like a steal and it would be a lot easier than piecing things together. thanks.