billlee

I've got a virgin 400 block from a 72 caprice. Would like to build it for my 81. I am running a 700r4 trans and stock rear gears 2.73?
I drive the car alot and am looking for good "off the line" performance and highway performance once its in o/d. Any suggestions for piston cam and head combo's. Block will be bored 10 over for cyl cleanup. would like to use the stock crank.
Thanks for help.

BKbroiler

People here will be telling you to put big aluminum heads and a roller cam in there. But, you're saying you want off the line power and responsiveness while in OD, and you have a low rpm iron crankshaft. Therefore, you want smaller heads and a mild cam. You could use GM Vortec heads and a Comp XE, flat tappet, hyd. cam. With a good carb it will be a tire roaster.

CA-Legal-Vette

I mostly agree with BK but I'd also suggest that you don't undersize the heads either. I build a SB 400 with Edelbrock 170CC intake runner heads. These heads flow really well and the idea was to keep the torque up and have good throttle response. I was kind of underwhelmed by the result. It could have been caused by many things but I think the heads were just not up to the task.

Also make sure that you can get 10 over pistons for your engine before you bore it. 30 over is the common size and you may not be able to get what you want at a reasonable price. 10 over is better for a 400 though.

L88Plus

^ I looked forever and couldn't find any at .010 over. I did find plenty at .020, that's what I ended up with. My block didn't need to be bored, the shop honed it to .020 with no problems, saved me the cost of boring.
I'd look at bigger than Vortec heads, too. This is a Corvette, not a tow truck. Something in the 200cc - 215cc range should be fine.

BKbroiler

Just as I expected.

BTW - I've never seen a tow truck that would outrun my Corvette, which has Vortec heads.

L88Plus

Probably not, but a 'vette with a similar engine and better heads sure will

Vortecs are fine for a 350, OK for a 383 if reworked but too small for a 400 in a light, fast car. They don't make good power in the upper range where you expect that kind of engine to shine...as it will with better heads.

BKbroiler

L88 - Did you read the original post completely? He's not looking for upper range power. He wants "off the line" performance and performance while in o/d, overdrive. I don't think he's too concerned with upper range.

L88Plus

IMHO, he'll have plenty of off-the-line performance by default, kinda goes with the territory of a 400. A 400 with vortecs runs like a hot 350, it's kinda building-down, restricting the possiblities of a 400. There's plenty of power left in those cubes to make it really shine, as long as it's not much more cash, might as well build it once and build it strong as opposed to a head swap later down the road when he figures out how much more power - and fun - he could have had with better heads from the start.
Just my .02

tt 383

The vortec heads are a good option, but if you want a small runner head in alum for about $1000 that flows pretty good the Trickflow 175cc head would be my choice. It will supposedly flow as well as a reworked vortec.

ajrothm

NO WAY would I put a 170cc head on a 400" motor....Unless it was going to be a stock type rebuild.....Penny up for good heads up front, keep the cam relatively mild and that will give you a strong bottom end-midrange motor and will live fine with OD....yet will not be choked up top....

I would go AFR 195 Eliminators and a hyd roller cam in the 228/234, .550/.570" range......That setup would putt putt along nicely at 1700rpms on the hwy yet still make a solid 475-500hp up top...... A good cruiser/daily driver....

A buddy of mine built a 383", 10.7-1 comp, some old casting Trick Flow heads, I believe they were around 200cc.....then he did a lot of porting on them, good valve job. He ran a Bullet HYD roller that was only in the 224@.050 range, around .550" lift....RPM air gap intake. That engine dynoed 490hp and he put it in a 3100lb Chevy Luv truck with a 200R4 and 3.55 gears, 2400 stall converter. It was his daily driver and and ran 11.30s@122.... He put 30k miles on that motor before he sold the truck...

tt 383

http://www.popularhotrodding.com/eng...ine/index.html
This is the build I would follow if I was billlee, either the vortec or the AFR build or sub with TFS, Eddy's, or IK 180, but note the port volumes, and the difference where the better heads pull away. Its not until 4000 rpm that you even get a hint at the better heads coming into their own. Thats with a decent sized hyd flat tappet for the street. Their are some things that could be refined especially with a lesser head than the AFR, like using a dual pattern cam and the 1.6 rockers. I have a feeling that the difference would be minimal if the vortec heads had a 2.02/1.60 valve job and bowl blend to cleanup valvejob. With 2.73 and weight close to what 3500 lbs? I would stay away from the bigger heads on this build.

Aflac

TT, thanks for that article. I have a 400 on the floor of my garage and am looking for the right way to go...

tt 383

I love that article because its done with a sense toward budget and 87 octane. Their is also some room for improvement in a few different aspects but shows what is capable with well matched components. I think a roller would have been a great addition to this combo and maybe extended the shorter Vortec power band in both directions.

Aflac

i'm leaning towards having my block machined to go with the roller. My boss has been bending my ear about it quite a bit

MotorHead

My friend who owns a machine shop wanted to put 215cc Vic Jr head on my 350ci. I ended up with 200cc Sportsman II heads and made near 300RWHP and 330 RWT.

Suggesting anything less than 200cc for a 406ci is...well I don't even want to say it. This losing or gaining torque deal is a bunch of hog wash
if you make more power your going to make more HP and TQ period.

Go ahead and put little heads on your 400ci if that's what the forum tells you but look at the chassis dyno on my old 355ci with the 200cc heads I also had 3.08 rear end and it was fine. I don't see any loss of Tq here



And here is my 406ci dyno, I guess I don't get this loss of torque thing unless it's like I stated, Hp goes up so does your
Tq it's simple. This 406ci was making over 450 ft / lbs at 2000RPM's. This is with the huge 215cc Vic Jr heads. They actually cc'ed to 219cc's. Will that get you off the line ?? You bet it will I do this stuff at
my own expense to see what really happens instead of the same BS being sent around in circles for years and years and never stops. Sorry for being so blunt but like I said I believe things that I can see, most of the time, not read about or hear about it

BLOCKMAN

I would opt. for the AFR 195 heads, We did build a 400 years ago with Vortecs that were mildly worked and on the dyno it made 525 foot pounds of torque and eas a real tire roaster.

We have seen on the 400 blocks that the cylinders and the decks are very thin and weak and plate honing on them is a must. If not leak it down some time at TDC and you will see what I am talking about

73BLWN

I followed the herd and bolted on a small port head, for low torque with an ealrlier 400 sbc build, and was so so so unbelievably disappointed. Do not make that mistake. The heads were the ones world product sells as a factory replacement for the 2.02 fuelie heads 30hp increase yadda yadda. I even had them bowl ported, and couldn't wait to get them off the motor. I gave them away just so I didn't have to look at them on the shelf, and bolted on a set of AFR 190cc heads and it felt like I bolted on a small blower.

So just like ajrothm said AFR 195's and around 230 at .050 with .500"(+) lift. Go with a roller if you can afford it, or any similiar hydrualic flat tappet and it will pull hard from idle to 6000 rpms.

I wouldn't be afraid of a larger port head like motorhead suggested, and firmly agree with him on the hog wash comment.

Good luck.

427Hotrod

I also wouldn't put a 170 cc head on a 400. Just seems a waste. Will it drive great and smoke tires? Sure...but don't be surprised when someone takes your old 350 and puts some heads on it and walks right by you. The Vortecs ARE good heads and can run well....but there is a lot better out there for not much more $$$.

We just did a 400 with Dart 200cc heads. It made 481 LB ft at 3000 rpm (as low as we tested) peaked at 520 lb ft at 5100 and made 555 HP at 6300 rpm. You could easily cam it down a little if you wanted to and move the powerband lower...and STILL have strong power well past 6000 RPM when you wanted it even with a small cam instead of having the heads choke it off.

Driveabilty is in the cam and tune. Look at a new Escalade....you can drive a truck through those ports. Anyone think they don't drive nice?

JIM

Vette5.5

Cam selection for a street driven engine has alway's been problem, as many tend to go larger losing low end torque. Maybe a few more tip's. First gear multiplication with a TH700r4 2.76 axle is very close to a TH350 3.42 combo. If flat tappet, Crane High Intensity lifter's could be of benefit as they bleed down some at lower rpm's, causing the cam to act smaller there. Also know of a few 400 build's where the oil pump bolt's extended beyond the rear main bearing cap, ruining the bearing. This is a good one to watch out for.

tt 383

You guys can say what you want, but they are good heads for the money. All the other heads are small too, but flow even better than the vortecs so what exactly are you's driving at? He didn't ask for track times or say he wanted 500hp, he asked about highway, OD trans lockup and using 2.73 gears, presumably with a stockish converter? Just because you can run a 400 with bigger heads and deeper gears and a converter for a multi purpose car does not mean its the best combination for what he wants and is inquiring about. I don't understand why everyone focused on the vortecs either, I wasn't pushing them but merely pointed out they would work well for what he intends to do with the car, and the combo in the article will be good for 11 sec slips and more problems he probably doesn't want to get into with all the driving he wants to do. I am surprised that EFI wasn't thrown out there too. Why buy AFR 195's if you are running stock manifolds and exhaust system, oand running a factory dual plane or factory carb. No one knows at this point what he will be running but everyone says "this" or "that" is a waste and have no idea of even a budget.........