I just bought a Chevy 400 small block to replace my old 305 and am looking to build a mild motor out of it. It's being bored .030 over and complete overhaul. I am buying summit Small Chevy SUM-152123 heads, and have an old edelbrock performer spread bore intake " will be buying a quadrajet 750 carb" headers 10:1 compression ratio. The car is an 87 monte carlo ss with 3.73 gears stock 200r4 tranny and I DO NOT want a stall converter. My goal is to have a car that pulls hard rite off idle. IT seems that most cams in automatics without a stall create a saggy low end which I don't want. I wont ever rev this past 5000rpms so I guess idle-5000rpms is that power band I want.


So to the question does anyone have a good suggestion on what cam to select from northern auto. I am buying there rebuild kit and it lets me choose a cam but idk what to pick. http://www.northernautoparts.com/Pro...CategoryId=610

 

Comp XE262 (12-238-2), or the Voodoo that's about that same size.

 

The Lunati 60102 is the equivalent and 60103 is a step up.

 

400s like single pattern cams. It's tough to feed those big cubes on the intake side. Much more so than an equivalent 350. If you don't want a higher stall converter, keep the duration below about 220* @ .050.

Now, small duration cams and 10:1 compression don't usually play nice with eachother in a 400. 400s build cylinder pressure like crazy. Fortunately you can widen the LSA of the cam and make it both docile and pull like a mule.

Somewhere in the 215* duration range on a 112* or even a super-wide 114* LSA will absolutely kick *** on a low-revving, (relatively) high compression 400.

 

Thanks everyone for the help so far! This one here matches your description pretty good and is one of the options. I cant find a rpm range on it though. CS1028R 214/214 DUR @ 50 .443 .443 LIFT LOBE 112 http://www.northernautoparts.com/part/ek-ek1923c

 

That's a generic, cheeeeeeep, non-competitive design. We call that "The Mild" cam, one step up from "The RV" cam which is the one in the same series that's 204° on the intake.

I would differ with the comment about 400s liking single-pattern cams; given the poor exh flow of most stock and stock-like heads compared to their intake, and the fact that having more cubes means more has to get through that port before intake charge can come on to replace it, all the factors that argue in favor of a bigger exh lobe would seem to be in place. Additionally when I've taken a single-pattern cam out (282S) and put a split one with the same int duration in (XE274), everything about engine performance improved. Of course some of that could have been due to just an altogether newer and better cam design (XE vs Magnum); but I'm pretty sure at least part was due to better cyl evacuation.

IOW, choose the intake duration to match the compression, RPM range, etc. that you are building for; then use a slightly bigger exh lobe to help make sure that when the int opens, the pressure in the cyl is lower than it is in the intake tract.

Other than that, Damon's advice is good.

DON'T use a generic copy of a copied generic copy of a generic design from 50 years ago, REGARDLESS of "specs". If the XE is a better cam than a Magnum, a Magnum makes that generic POS look like it was chiseled out of stone in a cave 10,000 yrs ago.

 

X2

 

I can offer that my build is 414CI with 210cc AFR heads, 10.4CR etc. My cam is 236/242 @ .050 ~.600 lift cut on 112 LSA.

It pulls down to about 1200RPM in OD but doesn't like it much. It will cruise at 1500+ but 2000 is better & smoother. Id say the "stall" speed would probably be around 2500RPM because that's where it really smooth's out and starts pulling hard.

If I were picking a cam again today I would probably stay in the 230/236 ball park and 108-110 LSA range. From what you describe a 224/230 on 108 may be a good choice.

My experience is that my car spends 90% of the time under 2500RPM and it's only once or twice a day I can really buzz it up and then it's only 5500 or so. Less duration, tighter LSA and decent lift for the heads chosen would be my suggestion.

 

thanks again everyone for the help! Well a few people agree that the xe262 cam is a good choice and it is around 214 degrees so I guess this is the cam ill choose unless someone has a better selection. 1300-5600rpm it says so it sounds like a good choice.

 

It should go to 5000 but not a whole lot after that. Heads are small and cam is small. Very torquey responsive motor tho

 

I agree with what the others have said. If it were me, I would get the XE262.

When I got my motor (a 406 too), it was a stock rebuild with an unknown cam. It turned out to be a Comp High Energy 268. I decided that was close enough to the XE262 to not change it. My engine idles at 650 RPM and is pretty much out of steam by 5000. Lots of torque. Like antman89iroc I can cruise in OD down to 1500 or a little less.

I would expect similar results from the XE262.

 

Honestly, with your goals, it would probably be a good choice. Even with my big-er heads and cam my 414 is done before 6K. Really 56-5800 is probably about peak. Haven't dyno'ed yet so that's just a SOTP guess.

I can share that when my engine was a 350 with 200cc pro comp heads I had a 212/218 cam and wished then it was bigger. I think you are always better to go too small rather than too large on a street motor but 5k comes up quick with 3.7x gears. Romp it and it's over very soon. Another variable is torque, 400's have a lot and I can pretty much waste 1st gear and 2nd has to be driven a bit so there is really too much torque to plant anyway. Also, published rpm ranges are generally based on A 350 so it'll most likely be about 500 rpm less on your motor. Just some things to think about.

 

That's exactly what I am looking for!! I don't think ill ever rev over 5000rpms so it shouldn't run out of steam for me. and like others are saying it'll be very responsive and torque which is what I am shooting for. Thanks guys you solved the missing puzzle piece

 

I think you're going to find it's marginal on pump gas with that cam. Widen the LSA or at least retard the cam 4* at the chain. Trust me on this. You don't want to be pushing 200+ PSI of cranking cylinder pressure with a street driven 400 on pump gas with iron heads. And you will with that cam installed straight up (it has 4* advance ground into it). Widen the LSA and/or retard the cam.

You need to kill some cylinder pressure but without resorting to a big lumpy cam. I've built basically that same motor you're building more than just once or twice. You should trust me on this. It's not quite like building a 350.

You know why I recommend a single pattern, wider LSA and/or retarding the cam a few degrees?? They all keep overlap to a minimum (nice street manners) but still allow for later intake closing which both helps fill those giant cylinders through small heads and reduces cylinder pressure and keep you out of detonation.

There is a method to my madness and I didn't come by it without some significant experimentation.

Take, for instance that little 214/214* cam you mentioned. Yes, it's got lazy lobes, but that is actually not a bad choice for what you're building (though I'd retard it 4* at the chain since it has 5* advance built into it). Those are quality cams, despite the bargain price. I've probably used a dozen of them over the years (Summit sells the same line under their house brand). Those slow ramps may not be sexy compared to a more modern, aggressive grind but they are very easy on the valvetrain. You don't need anything exotic in terms of springs, rockers or pushrods to work with it. Plus, it'll run dead quiet and last half of forever in street driving, just like a stock cam will. Also, those lazy ramps help bleed off some compression when the intake comes slowly to it's seat. Are you going to leave a few HP on the table? Yep. Are you going to care? Probably not.

 

Justbuy some dished pistons if you are worried

 

A lot of what Damon says makes sense. There's no arguing with experience and I've only put 1 performance cam in a 400+ci motor. My combo with 236/242 on 112lsa and 10.4 true static generates around 175PSI cylinder pressure. A smaller cam will generate more psi assuming the intake valve is closing earlier.

Now if you change those rear gears I think you may be able to take advantage of all that torque but I would probably want it to rev a little more than a 214 cam will. Just my thoughts here but for my combo I think 220 to 224 would be about minimum duration. 212/218 in my 350 was barely a cam to be honest. Again, stay conservative and "lazy" quiet lobes that last a long time are a good thing as long as the motor breathes ok and you have the rpm range you want.

 

Well they have this cam on the site. This whole cam selection is a big pain lol. Remember that I want my car to have lots of low end or burn out power.


2000-4500 RPM Range, 292 intake/292 exhaust Adv Dur, Duration @.050 218 intake/218 exhaust, Valve Lift .458 intake/.458 exhaust, Lobe C/L 110.




They also have this next step up 2200-5200 RPM Range, 290 intake/290 exhaust Adv Dur, Duration @.050 222 intake/222 exhaust, Valve Lift .447 intake/.447 exhaust, Lobe C/L 114.

 

You don't want that. ESPECIALLY not the 2nd one. It is the steamingest bucket of zoo dirt monkey plop that has been created in the last 50 years. Yes, you read right; that piece of excrement "350 HP 327" POS garbage has been disappointing hot-rodders EVERY SINGLE TIME they've used it for 50 years now.

50.

That's probably long enough that any sensible person willing to ask a question on the Internet and actually READ the answers instead of arguing about it, can figure out that IT SUCKS.

Get the Comp XE262 (12-238-2), or the Voodoo that's about that same size. They'll carry one or the other if not both.

Don't make it harder on yourself than it has to be. Click on the link on the page that goes to one of those 2 cams. Enter credit card poop. Done.

 

ok well if you think the xe262 will work ill try it out.

 

OBTW I've been building 400s for a VERY LONG time; probably longer than 2/3 of the people on this BBS have been alive. So although I'm no "expert" or any such thing, and make no claims of anything of the kind, I HAVE seen QUITE A BIT of what WORKS over the years, along with WHAT DOESN'T. I've even charged people to take out what they insisted against my advice that I put into their motors that I built for them and charged them for building, when they discovered that maybe I DID know what I was talking about after the crap they had me do didn't work like their inexperienced self thought it would. Don't be a moron like those people. LISTEN and profit from experience YOU DON'T HAVE TO PAY FOR THE CONSEQUENCES OF SCREWING UP to get.

 

OK. I'm not getting in a pissing match over this. Do what Sofa says.

 

I'd like to point out that my experience is with hyd roller cams. I presume from the specs the cams you are considering are flat tappet. Different animal. So when I said around 220-224 intake duration @ .050 that is roller cam specs. The seat to seat time for a roller cam would not be 292. That is a lot for a flat tappet cam. Sofa is right in the sense that putting in a cam with too much duration is a bummer.

 

Just done a 305 to 400 swap, ported #370 camel humps comp 256h cam 10-1 compression it pulls like a train. The cam is almost the same as the one in the gm 602 circle track engine very pleased with it runs great with the stock converter. Pulls great to 5k. Couldn't ask for a better daily.

 

how would a comp ****** thumper cam work as far as idling in gear?

 

Not well.

 

A diplomatic way to put it!!

There is EXACTLY one thing that kind of cam will do well: and that is, THUMP.

That's what it's made for. Nothing else.

In most motors, will give up significant horsepower, almost ALL low-end torque, and idle quality.