Thread: "fuelie" sbc 400

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Hello,

I have a couple parts and a problem
I have 400 block (#509), cast rotating assembly, 461 heads, 2500, stall th-350 w/shift kit, 9" with riduculus dirt track gears (yes I intend to run a solid spool)
The parts are for a 85 monte (stripped to about 2800 pounds), that we recently put a 350 in with a mild cam,
stock 441 heads and a 650 carb=not fast.

THE PROBLEM- I am making a street street strip car. The problem I'm having is in PICKING A CAM. Unsure of a safe rpm? there are z-28 springs in the heads, I would like to get right to a half inch of lift but don't know if that's safe? What type of intake should I run? The car has 1-5/8 long tube headers, am I going to need bigger ones? What gears should I get?

I am trying to stay on a budget any information is great!
Thanks

Welcome to Club Hot Rod – We’ve got several Monte lovers here so you’ll fit right in!

The fuelie “camel humps” are great heads however, you didn’t say which valves you have in your 461 heads.

The 461 and 462 heads with either 1.94/1.5 or 2.02/1.6 valves are the same castings. The only difference being the machining necessary for the larger valves and the relieving of the combustion chamber beside the intake valve for the 2.02 version.

A well built set of 461's with 2.02 intake and 1.60 exhaust valves is worth 25 to 35 horse over a stock set with 1.94/1.50 valves. These heads can definitely take .500 lift but the springs need to be correct. “Z28 springs” covers a lot and I would not want to risk bind so new springs would be in your best interest.

To make lots of RPM, you need to relieve/un-shroud the valve. A good machinist can trim the pocket (will add 2-3 cc) and you need to have screw-in studs and guide plates. Match the intake ports to your manifold and have the bowls cleaned up. Use stainless steel valves.

If you have 2.02’s and you want to invest screw-in studs and guide plates and the necessary machine work (probably $400-500) you’ll have some good heads that could handle a wide range of camshaft profiles (depending on rear end gears and tire size).

For purposes of this discussion, let’s assume you’ll shoot for about 10:1 compression ratio with flat top pistons. Much less will disappoint you in the “street strip” category. 8.5:1 is fine for a mild 305/350 that sees just daily commuter use. 11:1 can be a bit tricky on the camel squirt sold today as “premium” pump gas.

COMP Cams Thumper kit (cam, springs, retainers, locks, lifters, timing set) is K12-600-4 - 2,000-5,800 with lift of 0.479 intake/0.465 exhaust. This would be “streetable” with fairly good manners with the 2500RPM stall converter and 3:73 gears, Performer RPM intake and a 650-750cfm carb.

COMP Cams Magnum kit (cam, springs, retainers, locks, lifters, timing set) is K12-213-3 - 2,500-6,500 with lift of 0.501 intake/0.501 exhaust. This would require a taller rear end (3:90-4:11) and probably a 3000RPM stall. Couple this with a Performer RPM and a 750-850cfm and you be pleased at about 4500RPM, see God at about 5500RPM and need to change your shorts when you hit second gear at WOT (assuming your transmission is built to take this!)

This is just a thumbnail and my idea of what you “could do”. There will be others who chime in with different ideas. Lots of engine builders here who have tons of knowledge that you can use. Great thing about hot rods is there’s no single “right way” to do most things – we’ll tell you if you get to far afield and please bear in mind there are some strong opinions on this site so don’t be offended if someone disagrees with you.

Have fun,
Glenn

id use the comp cams 280-h

Hey Double Duce - if you're out there - re; my last post:

"This would require a taller rear end (3:90-4:11) and probably a 3000RPM stall. "

Should be:

"This would require a shorter rear end (3:90-4:11) and probably a 3000RPM stall."

Small numbers = "tall gears"
Big numbers = "short gears"

Us old people sometimes get our fingers in front of our brains!! Fortunately we've got friends on CHR and we look out for one another..

Also - make sure those steam holes are drilled on 400 SBC applications - see:
http://www.gregsengine.com/convertin...ds-to-400.html

Keep us informed!
Glenn

welcome double to chr. love the montes.

Thanks, alot of info!

Sorry for leaving out the all important details!

The heads, when I bought them they had already been to the machine shop. I took them to my machinist anyway and had him- boil, crack check, flat check, drill steam holes, install threaded rocker studs and guides, drill out the old push rod holes. As far as valve size they are an original 2.02, the previous machinist installed hardened seats and new valves. The ports have not been touched. The valve springs... my machinist and I had a long talk because I told him I want them to see a half inch of lift (that's why we put the threaded studs in them). This is where my confusion comes in. He told me if we test the pressure of the springs it will tell us and sure enough I was told there "good z-28 springs". He then shimmed/checked the height on every spring. I trust him but am still unsure of the exact cam (and lift)!
The engine (now short block) was pulled out of a one ton some years ago and sits in my shop. Yes I'm hoping it checks out, I would like to keep the stock crank, everything else is open!
The th-350 has already had the shift kit installed and is sitting next to a B&M2500 stall.
The parts were bought and biult for an el-camino but didn't end up needing them, so I already have them, but if I need to will change, side note- I have a factory 4-wheel drive th-400...

I am trying to stay on a budget but I will do whatever it takes to keep this a "happy setup".
Hope that helps thanks!
..

Glen, Don, Dave, and Pat McCarthy and Jerry Clayton can steer you down the straight path, it's what they do to make spendin' money - it sure ain't very narrow, though. I'd like to toss my two cents in, though: in my experience, as to cams and their manners, what might be getting pretty "edgy" in a 350 will turn out to be quite "mannerly" in a 400. I had 400s in most of my work trucks, and never left them be, I just had to mess with them a bit, and they are good engines in my estimation, and make great street/strip pieces. On a different note, the T400 you have will rebuild into a nice heavy duty trans with just the replacement of the output shaft and tailshaft housing from a non-four wheel drive, and a good performance upgrade build; not a tough thing at all.

Sounds like your heads are winners - I would still encourage a port match.

I concur with Rrumbler as to the 400 being a good motor with a lot of pull and as long as the steam holes are correct, they last as long as any SBC. Once they've overheated, there can be some real problems with cylinders and head warping. For a while, they were plentiful in wrecking yards, but not so much anymore..

The TH-400 is a great base for a bulletproof three speed.

Have Fun,
Glenn

Look at this link:
http://www.summitracing.com/parts/CCA-CL12-212-2/

280/280 Advertised
230/230 At 050 Lift
.480I/.480E Lift
2000 - 6000RPM

$185.95 w/lifters....

I think this is the one gassersrule 196 was thinking of?

Originally Posted by double deuce

Thanks, alot of info!

Sorry for leaving out the all important details!

The heads, when I bought them they had already been to the machine shop. I took them to my machinist anyway and had him- boil, crack check, flat check, drill steam holes, install threaded rocker studs and guides, drill out the old push rod holes. As far as valve size they are an original 2.02, the previous machinist installed hardened seats and new valves. The ports have not been touched. The valve springs... my machinist and I had a long talk because I told him I want them to see a half inch of lift (that's why we put the threaded studs in them). This is where my confusion comes in. He told me if we test the pressure of the springs it will tell us and sure enough I was told there "good z-28 springs". He then shimmed/checked the height on every spring. I trust him but am still unsure of the exact cam (and lift)!
The engine (now short block) was pulled out of a one ton some years ago and sits in my shop. Yes I'm hoping it checks out, I would like to keep the stock crank, everything else is open!
The th-350 has already had the shift kit installed and is sitting next to a B&M2500 stall.
The parts were bought and biult for an el-camino but didn't end up needing them, so I already have them, but if I need to will change, side note- I have a factory 4-wheel drive th-400...

I am trying to stay on a budget but I will do whatever it takes to keep this a "happy setup".
Hope that helps thanks!
..

"Z28" springs are usually installed at 1.735" and are good for 0.525" lift before they begin to coil bind. Problem is, they are good only for a flat tappet cam, not a roller tappet cam. If you have read any of my posts, you know that I am opposed to flat tappet cams because everything has to be exactly perfect or you will end up pooching a lifter. Money well spent is installing a roller cam and those springs will not work with a roller cam.

Originally Posted by glennsexton

Look at this link:
http://www.summitracing.com/parts/CCA-CL12-212-2/

280/280 Advertised
230/230 At 050 Lift
.480I/.480E Lift
2000 - 6000RPM

$185.95 w/lifters....

I think this is the one gassersrule 196 was thinking of?

Seems like a very good shaft and good match to me, so I have some parts to order and work to get done! Thanks guys

I'll put something up when I get it done because I'm sure I'll have some more questions for you guys, thanks

Alright I ordered it. cca-812-16. Question the journals are 1.869. Just got done measuring them. They are all within .0005. thats probably better than me so I was glad there but, Was I suppose to get one for a 400. In my book "haynes manual it says that 400's have bigget journal sizes? Is it just something I can tell the manufacter of my rebiuld kit and get bearings with a 400 od and the 350 id? thanks guys, it's going just slowly. Clearing up some confusion would be great.

The main bearing journal in a 400 is bigger--the rods the same as 350

Your talking about cam journal size above at 1.869--they are the same

Originally Posted by glennsexton

Look at this link:
http://www.summitracing.com/parts/CCA-CL12-212-2/

280/280 Advertised
230/230 At 050 Lift
.480I/.480E Lift
2000 - 6000RPM

$185.95 w/lifters....

I think this is the one gassersrule 196 was thinking of?

I have this cam in my 383 and like it a lot. Street friendly but it pulls like crazy. It is also not as hard on the valve train as Comp's XE line of cams. If you use a flat tappet cam, it is critical you break it in properly with one of tlhe new break-in oils. And for added insurance, use an oil with higher levels of zinc like Royal Purple XPR.

that 280H as reccommended is a good one, with your combo i'd seriously consider the 286H cam - i believe it is referred to a the z28 cam and matches well with the springs. It is an rpm cam and you should select a tall openplenum intake.
480/480; 287/287 advertised duration (231/231 @ v.050). Great cam, i've used a bunch of them.