camaro71633

I am putting together a small block 400 for my 89 camaro rs and would like some opinions on the possible cams i have picked out. The short block i am using is originally from a 76 caprice and is a 3951509 casting 2 bolt. It is all stock and has ~80k mi on it. I have a fresh set of 3951598 heads for it that have new valves, screw in studs and guide plates and where lightly ported. I would like some input on cam choice. The car is stock weight and has a presumably stock turbo 350 trans and 3.43 gears.

The 2 cams i have picked out are the summit K00172 and the K1103. My dad has the crane version of the '172 cam in a stock 350 in his 81 c10 and i like the way it idles and runs. I have also heard good things about the 1103 cam as well so i am undecided.

While I would love to go to a roller cam it just isnt in the budget at this time so I am sticking with a flat tappet this time around.

Damon

With the low compression and stock stall in the trans you don't want to go very big with the cam.

The other consideration is that you are using factory heads and I don't know if you've modified them for any extra lift. For now, I'll assume they are maxed out around .460-.470" lift.

The 00172 has a rather tight 108* LSA and I don't think you're going to like how it idles and behaves with the rest of the combo. Check out the K00042 instead. I know, it's a single pattern cam and everyone hates on them, but my experience is that 400s with mediocre heads LOVE single pattern cams. They fall off faster in the upper RPMs, but so does the 400 in stock-ish form anyway. They make the most of where the 400 really shines- midrange torque. I ran mid-13s with a 400 almost identical to yours with a cam 4* SMALLER than this one for years. Street tires, stock TH350 trans, 2.73 gears in a full-weight Malibu. I also towed my boat with it. (I later upgraded to a set of Dart Iron Eagle heads and went 13.00000000001 @ 108 MPH with no other changes.)

K1103 is a viable choice as well, but make sure your heads can handle the .465" lift on the exhaust side with a little room to spare.

Sure, there are better cams out there than the old school Summit grinds, but the quality of the Summit kits is actually very good for a "white box" kit, and the price is hard to argue with.

camaro71633

The heads have aftermarket springs and retainers. The guides have been cut down for more lift. iirc the guy i got the heads from said the springs are generic "z28" springs so they should be good to .550 lift.

One of the reasons I was thinking about using the '172 cam was to kill off some of the low end torque to help the 10 bolt and stock trans live.

Damon

I ran a stock-ish TH350 in mine (basic rebuild + shift kit) and an even WEAKER 7.5" 10-bolt in the back of my Malibu for years with that motor. Street tires only, though. As a matter of fact, I only upgraded the rear a few months ago when I decided to go a little more dragstrip-oriented with the car and use DRs. Trans is still the same one I rebuilt so long ago I don't even remember any more.

Eventually, you WILL break the 10 bolt, no matter what you do, so I wouldn't worry about it, just plan and save for that day. The TH350 trans can stand up to a mildly warmed over 400 indefinitely, though.

ex-x-fire

I'd really consider getting some vortec heads, this'll up the compression ratio & the air flow too.

67Blast

This is simple.
Comps 256H.
It will be real tame in a 400.
The 262H would make a better choice if you could blend the bowls on your heads, and was willing to run a little stall.Maybe 1800-2200. 3.23-3.73 gear.
I used to run a Perfect Circle 280H in a .060 over 400. Loved it. But fuel milage sucked. And tires didnt last long. 3.42 gears. It was a beast. But that was in 1986.

D_Smith87

Basically anything in the range of a "rv" cam .440-.470ish lift and under 220 duration/anything that reccomends UNDER 9-1 c.r for a smogger era motor, 400s make good power, no need to go huge on them anyways to move a light car like a third gen

anesthes

iTrader: (12)

I have a 400, bored .060 over. (412). It swallows up the cam like nothing else. You need a ton of duration to pull to 6k rpm.

-- Joe

rb85TA

Put the single pattern cam in it, it'll sound great, it's cheap & gets you going for now.
Then make a plan for a real build, save some money. ... until you think you have enough to start &...........SAVE SOME MORE $$$$$! LOL

D_Smith87

[QUOTE=anesthes;5949964]I have a 400, bored .060 over. (412). It swallows up the cam like nothing else. You need a ton of duration to pull to 6k rpm.

For a cam that pulls to 6k in a 400, thats a 6500 rpm cam in 350, which is where they rate small block cans, he'd need to totally go thru that engine and get some 9.5/10-1 pistons in there

rb85TA

Yeah, there's a lot that can be done, but sounds like he just wants to get it moving again with a little rumpity rump cam.

fireburdluvr85

The way you word your original post has me a bit confused, presumably a turbo350 as in you'll swap the 700r4 for a turbo 350? Reason I ask is a lot of people I know still think turbo 350's were in third gens.
I had a 76 caprice 400 with an "Rv" cam years ago in my 85 trans am. Barely have to rev them to get going. You'll enjoy it as I enjoyed mine with 3.23 gears and a 700r4. Pretty good gas mileage too

camaro71633

My car was a v6 car originally. The guy i bought it from had a turbo 350 in it and gave me the mount adapter when I bought the car. I want to convert the car to stick at some point but I am going to do it later on down the road. I would love to to a ls and t56 swap some day.

Thanks for all the suggestions. I plan on taking a trip down to summit racing on friday to get the needed parts to get the motor put together. I will update the thread with my progress.

This build is just to get the car going again I just happen to be using a "good" motor. This car has had so many different motors in it between the last 3 owners it isnt even funny lol.

rb85TA

ARE you still running the th350?
Just remember, when you do go Ls & t56, you'll need motor mount adapters ( or tubular K member with Ls mounts ) & new trans. X member.

camaro71633

Yea im still running the turbo 350. I know about all the stuff required for the ls/t56 swap I just have not started gathering parts yet. My car would be a nice candidate for such a swap as it has not seen salt or a winter in over 15 years and is in really nice shape for a snowbelt car. In the 10 years I have owned it I dont think I put more then 50 miles on it lol.

rb85TA

I hear that! My project is an '85 TA with 20774.6 Original miles on it & I've owned it for a year & only the 3rd to own it. It spent most of it's life in a showroom.

D_Smith87

See thats what some people dont get you dont need a nasty idle and 240@.050 to make a 400 have good power

fireburdluvr85

I usually ticked 24mpg with mine. Of course if I got into I'd break stuff but it was fun. Wish I'd kept mine. Broke the crank snout and balancer off driving home one day. OP I hope you enjoy it as much as I enjoyed mine.

rb85TA

D_Smith, you're right about that.... ,but with a comp292 (244@.050), they got a NASTY SOUND TO THEM & MAN DO I MISS MINE☺

D_Smith87

that must have been quite a motor, with some good 200-220 cc heads 400s can put up some real wild power numbers

rb85TA

Back then, I was married & barely able to get it built ,so I had to use what was available. .. a set of 462 cast double hump's, had new seats (2.02 & 1.6)put in with Manley valves & isky springs, fully ported using an SF600 flowbench ( it's funny & sad now.... to think that 100 hrs of porting & flowing those head's only yielded 277 cfm @ .600 & .650 lift. Head's today do that or better outta the box LOL ).
But, it was all I could do then. Learned a lot with that one & the school in Houston shortly after ( you may or may not have heard of them... the School of Automotive Machinist ,SAM for short), they have competed in the EMC & several race events that they run in competitively.

D_Smith87

Ive heard of that, and thats impressive cfm numbers on any cast small block chevy head

rb85TA

It's not bad for sure, but the head course instructor said that I could have gotten as much as 288-290 out of them ... if I hadn't started porting before I learned how to do it right.
So, now ( since I don't have access to a flow bench), I'll do gasket matching & light bowl blending. Anymore than that, I send it out

D_Smith87

I bought some budget aluminums, im gonna flow them stock, then have my machinist do some bowl work then flow again

rb85TA

Yeah, gasket matching to a 1206 & some mild bowl work with a good 4 or 5 angle valve job will wake them up, ( on just about all of the "cheaper" head's ).
Sounds really good, keep us updated. ... I love a good build thread

D_Smith87

Im running them with a comp xr288 and 1.6s, if i can get them to flow over 265 cfm, i shouldnt have a issue making a 500 horse 383 with a dual plane

D_Smith87

At .550 lift

rb85TA

Which head's did you get?

D_Smith87

Some skip white 200cc heads

D_Smith87

Bought them to slap on my budget motor but that blew up

rb85TA

I haven't heard anything about them. Make sure the machine shop pressure checks them before putting any time into them. That way, if they leak. .. you can send them back in exchange for another pair.
Once you know you're dealing with a solid foundation, you can proceed with getting them where they need to be for your combination.
What is the duration @ .050 ?
What is the cam ground on a 108* ?
Compression?
500 is not as hard to achieve anymore ( with the right parts & properly assembled with the right tolerances ).

rb85TA

I built a 377ci sbc for a friend, 10:1 compression, world products iron heads, lunati flat tappet with 245/245 @ .050 .550-.560 ish lift, single plain & 750 demon. ... it made 476 @ the wheels on a mustang chassis dyno.

D_Smith87

236/242 on a 110 lsa,.520/.540 lots of dynos with this cam out there, my buddy ran this in his iroc on both a set of eq vortecs and afr 195s, fast in both scenarios but hard to compete with afr

rb85TA

Sounds good, don't remember exactly (except the duration ), but it worked absolutely great!

camaro71633

A new job has slowed progress on my project but i am slowly making progress. I have the motor almost ready to drop back in the car but want to do some under hood clean up first. Hope to fire it next weekend.

rb85TA

That's understandable, I gotta pay my bill's before I pla you too .
So what did you decide to do ? (Cam, which one? Intake, carb or injection? , etc. ..).

camaro71633

I ended up with a k1104 (224/0.466) cam that a freind had bought and never used. He decided to go roller when he found out the block he had was no good. (was already .060 over)
I am using a old style eddy torquer intake and 1405 carb at the moment. I would love to get efi of some type for it I kinda like the hsr setup.

Me and my dad spent the day starting and running the motor on our ******* test stand. We just left the motor on the stand and hooked the cherry picker to it for extra support. We had some timing and fuel supply issues but once that was worked out she fired right off and ran good. I took a potato quality video of it running. I need to get a good set of plug wires a set of collector gaskets and a starter then its time to drop it in the car.

rb85TA

Good deal! glad to see you got it going, once you get it all worked out ( in car & driving ), you can plan & save for the future build .

camaro71633

Got the motor set down in the car the other night and almost immediately ran into issues. This is the third small block I have had in the car and i have always used the same mounts but for some reason the front of the oil pan on the 400 is sitting right on the tie rod I will start another thread about that to not clutter up this one. The motor is almost ready to fire on the car It just need the front drive stuff the torque bolts and exhaust put on. I will post more pics and videos when it runs.

https://www.thirdgen.org/forums/tech...tting-tie.html

rb85TA

It should be the same as all the other sbc's. I put one in an 85 TA .... wait. ... no I had a friend build me a set of motor mounts that pushed the engine back almost to where the distributor touched the fire wall.