spartyon

I am looking at getting some better heads, currently looking at the World Motown 220s. I know they are overkill and I think they are on the big side but the techs at Bill Mitchell has sparked my interest. Either way I will need some new springs for the heads that I do end up purchasing. Below are my cam specs. Thanks for the help!

Part #: Speed-Pro CS187R
In. Dur. @ .050": 244deg.
Ex. Dur. @ .050": 244deg.
In. Lift: .510
Ex. Lift: .510
Lobe Sep.: 108deg.
Adv. In. Dur.: 318deg.
Adv. Ex. Dur.: 318deg.
Valve Lash: Hyd.

Dialed_In

iTrader: (3)

what are you trying to do with the car and what kind of shortblock are you putting these parts on?

spartyon

Well, 3 years ago when I bought the shortblock I chose this cam for mild street cruising. I want to drive it on weekends and burn up some track. I have to toast my old man's 69 Mercury Cyclone. Here is what my buildup consists of, so far.

383 shortblock 10:1w/64cc heads, cam listed above, Team G intake, Holley 750, and maybe 150-200 shot of juice (still haven't decided).

Basically I just want a stout performer. I have a new pair of cast gm 1.94/1.6 heads that I was originally going to put on but want more. Looking for around 4-450hp.

My whole thing is that I don't understand what to look for in seat pressure, installed height, etc.

Sonix

iTrader: (1)

speed pro cam? The specs on that make it sound pretty tame, ie. LAZY ramp rates...
my 227/234 hydraulic flat tappet has more lift then that cam, and SIGNIFICANTLY less advertised duration...

The springs just need to support that much lift, then you need your seat pressure to be whatever the cam manufacturer suggests. Usually the cam will recommend certain springs.

That cam would do well with comp986's, they tend to work pretty well with most high perf cams that aren't too huge, or too small.

sofakingdom

iTrader: (1)

That cam is exactly like the old generic 234/244 .488/.510 cam, familiar to all these days as the "Edelbrock RPM" cam; except that it has the same lobe (the one the "RPM" cam uses on the exhaust) on the intake too.

Not a particularly effective cam. It's very old, very lazy, and designed for the days before aftermarket heads and aftermarket valve springs even really existed. It opens the valves slowly, stays at high lift for only a short portion of its cycle, and closes them slowly. The valve spends most of its time at relatively low lift.

If you want to win races, it's not a real good choice.

Given that the cam is about the single least expensive component of a motor, there's no point in using anything less than the absolute best choice for the rest of YOUR combo. In other words, why would anyone build a multi-thousand dollar motor, and then cripple it with some POS $50 cam, just because they "got it for free"?

Unless you're building a 427 or something, those heads are probably too large. If this is a 350, you'd do better with something in the 200ish intake port range. On the other hand, if this IS a large motor, then why would you buy heads with fire-hose-sized intake ports, and then use this itty bitty no-lift cam, that just sort of barely cracks the valve open a bit? That would be about like plumbing your bathroom sink with 1" pipe, and then turning the faucet on to where it just barely drips.

All in all, that's a BAD combo. While it might easily beat some 35-year-old FE motor (which itself is a relic from the Stone Age, and already was in 69), it's still a phenomenal waste of money to get to that point.

I'd suggest some Dart Pro1 200 heads, a Comp XE284 or XE294 cam or a similar grind (aggressive ramps) from Lunati or Isky or Crane or Crower, and whatever springs they recommend for it.

As far as picking springs for those old lazy slow ramps on the el cheepo cam, look at what the Edelbrock RPM cam requires; since that cam is a copy of the same copy that the RPM cam is a copy of, the springs that will work on the one will work on the other. Comp 986 or 987, or the stock setup that head mfrs put on their heads for hyd rollers, will work fine. All you need is about 120-130 lbs on the seat, and about 325 open.

spartyon

Yeah I know its a lazy cam now, 3 years later. I bought the shortblock when I really didn't know much and went off the advice of a dirt track engine builder. I do plan on upgrading later to a bigger cam but want to be prepared for the future upgrade. I spose now is the time to change it though before it goes in.

The Cyclone that my dad has isn't a plane jane clone. It has a hopped up 600hp 460 in it. It is at the shop right now getting a new rear clip. The only upside I have on his is the weight difference. His is a boat anchor.

I just looked up those two cams that you listed and if I am going to get some great heads, is it possible to pick out a bigger cam? Or would those be my best bet to 4-450HP ground pounder? There descriptions say that they like gears and 2800+ stalls and I currently have a beefed 10bolt (as beefed as they can get) with 4.10 gears and decided on a th400 with a 28-3000 stall.

Sonix

iTrader: (1)

A 383 stroker motor will eat up the duration a bit. When it says the recommended RPM range, drop it by 300 RPM or more, that's what the 383's more cubes will do.

With those heads, a big cam like sofa mentioned, you can be up in the 500HP range (with all other mods matching of course.)

your gears sound about right, do you have your convertor picked? Sounds like you haven't yet? Decide on your desired power band (remember, higher = more HP), then pick the heads, cam, and convertor to all match.
You're going for some big power, do you want to pony up and go to a roller cam? Either way, I think a solid cam would fit the bill for you, give you more top end power...

spartyon

I know, and all of this has peaked my interest but then I have to start tearing apart what I've already done and start fresh. Plus a solid cam is getting costly. To be honest I wasn't even thinking of 500HP. My plan was to be in the middle to high rpms. Somewhere around 2800-6000. I know this will mostly be driven on the street but I really want to take this thing to the track. I know a guy that just bought an 8th mile track and will let me run there.

Considering my buildup so far, do you really think that cam will get me to 500HP? So far the only thing missing are the heads, if I get the xe294. What else would I need?

spartyon

Well, I just bought a set of the Motown 220 heads direct from Bill Mitchell. What a long story, but to make it short he assured me that they will work wonderfully on my 383 with the comp xe294. I wanted 64 cc heads to keep my compression at 9:1. He again talked me into the 54cc head with a .051 gasket. He said that would put me around 10:1 compression which is perfect for pump gas, that is what I was really worried about anyway. Now with the heads out of the way, is the comp xe294 really the way to go? I tried to punch the numbers into my desktop dyno (cheap freeware) and came up with 475HP at 4800rpms and 607 ft/lbs of torque at 4500?(can't remember now). That is a lot of torque but it doesn't seem right to me compared to the hp. Anywho, would that cam be the best choice for my combo or could I possibly go bigger? If I am going to pull the shortblock apart and change heads and cam I want to get the most out of it. The numbers look good to me but those are speculated numbers and I probably entered the data wrong in the program.

Sonix

iTrader: (1)

that torque seems pretty high, and peak HP is at too low of an RPM. That's definately optimistic.

That cam, with the big heads, will work well, but it'll be high RPM power, 3000-7000RPM i'd guess. That's a big cam, and big heads, i'd expect big power anyway.

that cam will bleed off a lot of pressure, 10:1 on iron heads, *with that cam* will be perfectly fine on pump gas. No worries. Heck, i'd think about even going higher. If you haven't installed it yet (have you?) I'd go with a thinner head gasket. That'd bring up your CR, and bring quench back into play.
I'm running a "268" cam, with 10:1 on iron heads, 91 octane fuel. Runs fine for me.
54cc, and 10:1 on a 383 doesn't sound right. Big dish pistons?

Mkos1980

iTrader: (8)

Comp 987 Springs.

spartyon

No, I am using flat tops. I had the shortblock built by JR Motorsports, a midwest circle/dirt track company. They told me the with 64cc head it was at 9:1. I was just worried more about compression on iron heads. I heard they don't like it too much. Plus 10.5:1 was pushing the envelope on pump gas, I thought. I did not get the gaskets yet. Still planning that out and will buy everything with the cam. Comp has a kit with the cam, springs, valve lock, retainers, and lifters for 350. The springs that come with it are the 986s so that must be what comp wants them to be run with.

sofakingdom

iTrader: (1)

Right, 986 is fine for the XE294 (Comp would know ); you'll also note, if you look in their catalog, that the 987 is the "premium" choice. So either will work fine. It's not impossible that Motown offers one of those as one of their spring options that you can buy the heads with.

I agree, those sim #s look very screwy. If I was just going to guess, I'd expect to see peak numbers something like 525 ft-lbs @ 4500, and 500ish HP @ 5800 from your combo, from a sim.

Without knowing the rest of your combo - some of those pesky details like intake, exhaust, converter, gears, weight, intended use, your tuning ability - it's going to be pretty tough for anyone to "optimize" your cam for you. But if the head mfr likes it as going well with their head properties, then you are probably already within the "reasonable" range at least.

spartyon

Well, this is what I am going to go with then.
383 stroker
Motown 220 54cc heads (2.08/1.6)
Comp XE294
Crane Gold 1.5 rockers
Weiand Team G intake
Holley 750
Hooker Long Tubes
Th400 (3000 stall)
4.10 gears

As sonix already stated, is there really a big difference in quench with the .051-.041 head gasket?

gmgod

A 383 with flat tops and 54cc heads is going to have about 11.5:1 compression with a .025 deck height and .051 gasket. You would really be better off with a 64cc head and .026 gasket and better of still with a 68cc aluminum head and .026 gasket.

I suggest you measure your deck height first, buy the appropriate gasket (the one that gives you about .040 piston to head clearance) and get the 64cc chambered 200cc intake port pro ones or the 68cc chambered afr 195's.

Sonix

iTrader: (1)

yea, spartyon, something doesn't add up with your compression calculator.

United Engine and Machine Co.

use that to double check. Hint, a stroker has a longer stroke (duh), which means it bumps up the compression, if nothing else is changed. That's why many 383's use HUGE 22cc D dish pistons.

With flat tops, you want a large chamber head. And with flat tops, a .040" quench is ideal. Check your deck height on your block, then get the gasket that will total .035-.045" height (deck height plus gasket). Then pick heads with chambers that will give you 10-10.5:1 CR, if you want iron heads, and 11:1 or so with aluminum heads.

If you want another opinion, call up comp cams, their tech support is good, tell 'em you want to use that 294 cam in a chevy 383 stroker motor, with iron heads. What static CR do they recommend? They'll probably say high, like 10.5:1 or so. I'm telling you, it'll bleed off lots of cylinder pressure. If you *don't* go high on the CR, it'll be a dog down low. And it'll run ok on pump gas, due to the BIG cam.

spartyon

Okay. I will have to call JR and ask them what they decked the block at. Bill Mitchell said that it would be 10:1 but 10.5:1 is a possiblity. He told me it probably won't be more than that.

spartyon

Alright, thanks guys. JR told me that their new 383 blocks are 10:1 but they did have some that were 9.5:1. According to their calculations they told me I would be around 10.5:1 with a .041 head gasket. Stupid me, I didn't ask for the specs and try the calculator myself. I will call them after I get off of work. Hopefully this motor turns out to be awesome.

Sonix

iTrader: (1)

yea, if you're building a motor of that magnitude, i'd HIGHLY recommend writing down every single spec measurement you can get your paws on. You're paying big $$$ for that motor, they'll have measured stuff, so it's a very good idea to have those #'s lying around, for when you do need it. Ring end gap, main and rod bearing tolerances, deck height, etc. If the rotating assembly was balanced, etc....

Yea, based on what? a block doesn't have a CR, what head did they base that off of?
Do you have the block sitting in your garage now? Measuring the deck height yourself is most accurate, and then you can sleep well knowing that you know exactly what you have. feeler gauge and straight edge is all you need.

That question: "what valve springs do I need", sure balooned eh?

spartyon

You ain't a kiddin'!


I will have the engine next week. I moved and the car is at my dad's which I am picking up the engine this weekend after the NHRA race in St. Louis, hopefully. How would I go about measuring the deck height. I assume that is the distance from the piston to the deck?

Sonix

iTrader: (1)

yep. turn motor over by hand, until piston is at TDC. (use balancer if you're sure it's right, or piston stop...)

lay straight edge across bore, along piston pin centerline, and slip feeler gauges under, go-no-go style, and determine height gap. Look for .010-.045" ish area. You can do all of them, or just #1 and #8 sorta thing, ie the corners, and average it.

spartyon

Okay, actually had dad do this and surprisingly he did it right away. Turns out to be .010".

Also, just received a call from Bill Mitchell about the heads. Turns out they talked me into 54 cc heads because that was what there were liquidating. Gee, thanks! Well, they called and said that the heads they were sending out were missing a few intake and exhaust seats. I went off and told them that I knew I wanted 64cc, which they didn't have any left. Well, he suddenly found a set and is sending them out instead of the 54cc. Good, now according to the calculator link
4.00" bore
10.035:1 with a .041 gasket
10.345:1 with a .028 gasket
4.080" bore
10.081:1 with a .039 gasket
4.100" bore
10.65:1 with a .016 gasket
10.548:1 with a .020 gasket

These are static compression numbers with a 6cc piston with is what the reliefs are on my flat tops. I am thinking of getting the 4.00" .028 or the 4.100" .020 gaskets. Leaning towards the smaller of the two. 10.3:1 gets me in the middle. Gonna start ordering some parts tonight. Can't wait to start assembling the heads. Too bad the freaking valves are so expensive (Manley race).

Sonix

iTrader: (1)

a 383, is a 4" bore, with a .030" overbore. So a 4.000" gasket bore won't work. Most 350 chev gaskets have a 4.166" bore.

with .010" depth, use a .030"-.035" thick gasket.

ok, you're seriously doing something wrong here. I attached a screen shot of what i'm getting with your numbers:
(remember, 3.75" stroke!)

Sonix

iTrader: (1)

so the only variable you really get to play with now, is head chamber size.
I'd shoot for a 70cc chamber, if such a one exists.

spartyon

I know that the bore is 4.030 but a standard 350 is 4.00". I figured that there would be an overlap of .030 but that shouldn't interfere with the valves or piston travel, just compression.
----------
This is what I entered in that calculator:
64cc
6cc
.041
4.00
4.030
.010
3.75

This time I came out with 10.7:1. God I hate math. Different answer every time!

Sonix

iTrader: (1)

there ya go. 10.7:1.
Ok, you can't use a 4.0" bore gasket on a bored out 350 block. big no no. It'll hang over the bore edge, and over the head chamber, it'll just be sticking out in the chamber. bad idea.

if you can still change the heads, i'd go with larger chambers, and optimize your quench via the head gasket (.040" total, +/- .005").

use the dynamic compression ratio calculator on that site as well, enter your intake valve closing angle for that (I think). That's the useful compression ratio that your motor will be living with. Keep *that* under 8.5:1 and you'll run on pump gas ok.

spartyon

World recomends FPP-1003 which is a 4.166" bore with .041 thickness. That left me with 10.6:1.

Sonix

iTrader: (1)

:shrug: I gave you my opinion, and what i'd do, if I was in your shoes. I think i'm out of stuff to say . Now you've got a good calculator, and all the options open to you, it's up to you to choose.

Maybe other members here have thoughts on the best possible option?

spartyon

No, don't get me wrong I am just going off all the numbers flying around in my head. I thank you for all of your help. Still crunching numbers and everytime I try it takes me back to the beginning. Thanks a lot for your help though. I have learned a lot in this simple thread on choosing valve springs!

1989GTATransAm

iTrader: (3)

I would bet the .041" head gasket recommendation is if you zero decked the block. You did not and left the piston .010" in the hole. Sonix is right regarding the quench and your dynamic compression ratio. Those are the keys to detonation. .035" to .040" on the quench and no more than 8.5 dynamic compression ratio. You just need to do the math. If need be it is not hard to open up the combustion chamber some more to lower the compression.

He is right regarding the head gasket. You can't use one with a 4" bore as it will hang out into the cylinder when compressed and most likely will not seal properly. The smallest I would recommend is 4.065".

Me, I like the Comp Cams beehive springs. The 918's would probably work just fine.

spartyon

I know. I am still playing around with numbers and reasearching. Bill Mitchell again, I should know by now not to fully trust them since they told me to use 54cc only to find out because they wanted to get rid of them, but 10.6:1 would be borderline of pump gas but they say to use FPP-1003 which is a 4.166" bore with .041" compressed thickness. That puts me around 10.6:1 and they are telling me that is fine. Who knows. I am still playing around with numbers. In order to obtain the dynamic compression the calculations ask for the intake closing point in degrees ABDC @ .050. How would I go about finding that using the comp xe 294 cam?

1989GTATransAm

iTrader: (3)

If you are using the United Engine calculator don't use the .050 figure. Use the actual closing of the intake valve past bdc. With the size of the cam you have I would think it would be something like 80 degrees.

spartyon

And how can I go about finding the actual closing of the intake valve past bdc?

daverr

iTrader: (1)

I had the same heads on my old engine which was a 350 (0.060+). i had alot more compression than u (close 13 to 1) . THe motor made 450hp 400TQ on the dyno.
If i were u i would have heads and intake , flowed and ported professionaly. I didnt and regretted this big time. dont skip this step. makes cam selection easier.With my new engine I did this step and very glad with the result.Dont look in magazines for flow numbers, pay someone to flow them.

Sonix

iTrader: (1)

sparton, that spec is listed on the cam card. Not sure if you can find it on comp cams website, probably, but i'm not sure where to look.
If in doubt, call 'em up and ask.
ok, i'm feeling generous...and bored:

Camshaft Specifications


looks like 73. That gives 7.944:1 DCR. That's peachy fine. Still, i'd like to see this:

Sonix

iTrader: (1)

oh, and just to toss this into the mix, in case you aren't dead set on that comp cam, here's one I like: ( I have the 60103)

Lunati voodoo 60105.
"Description- Hydraulic: This is possibly the most powerful hydraulic cam ever designed Designed for Very Hot street/bracket race applications, this cam requires a minimum of 10.5:1 compression, 4.11 gearing and 3500 RPM stall converter. Works with up to 250HP nitrous, and pulls Very Hard past 6500 RPM when coupled with the correct parts. The baddest of the witches' brew, this cam is destined to rule the street. If your scared buy a different cam "
adv: 284/292
@.050 241/249
lift .525"/.546"
LSA/ICL 110/106
Hyd/Hyd 2500-6600

Beauty is, less advertised duration, slightly less duration @.050, but more lift. Less of the lumpy cam feel, same great big cam taste... err, feel.

spartyon

I did decide on the xe294. After some more research I think that will be a great choice. Thanks for the help on those numbers. I checked comps site and it said nothing about the intake closing numbers. Guess I didn't look hard enough. I was actually surprised to see 11:1 static and 8.27:1 dynamic. I punched in the "recomended" FPP-1003 gasket and got 6.8:1 with valve close at 88* because they say add 15.

I don't think I am going to port the heads. I just spent over a grand that I wasn't expecting on changing the cam and heads with manley raceflo valves. Damn those things are expensive! Just glad a complete cam kit was only 359. Now I need to get gaskets. I am seriously debating the .031 but might go with the "recommended" .041. It should still run like a raped ape...I hope after all this "sudden loss of income"!
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Also, why do they rape you on head gaskets? 40 bucks each!!

Sonix

iTrader: (1)

the "add 15* means, if you use the .050" measurement, they throw in 15* as a fudge factor. This is supposed to represent the ramp rate. Use the .006" that they give you (that I used), I think it's more accurate that way. 8.2:1 is a-ok.

Ok, your call, .051 vs .041 quench distance isn't the end of the world, but "they" say it's a good thing to optimize your quench. :shrug:

ha! I paid $40 for intake gaskets locally! That's why I went with a summit gasket kit, $30 or something for every gasket under the hood basically. Even if I throw out half those gaskets, i'm still winning. Sweet deal.
For an "offsize" head gasket, expect to pay more, like $50-90+ ("normal" size is the .041" thickness usually. A .026" or something oddball would be more expensive)

spartyon

I crunched some more numbers with the following gaskets using 6cc pistons. Let me know if you likey cuz I think I am starting to get the idea and hang of this.

MRG-1052 Bore (in): 4.140 in. Compressed Thickness (in): 0.020 in.
(static=11.249:1 Dynamic=8.415:1)
MRG-1134 Bore (in): 4.130 in. Compressed Thickness (in): 0.028 in.
(static=11.022:1 Dynamic=8.251:1)
SCE-511144 Bore (in): 4.140 in. Compressed Thickness (in): 0.039 in.
(static=10.716:1 Dynamic=8.029:1)
SCE-011152 Bore (in): 4.155 in. Compressed Thickness (in): 0.021 in.
(static=11.214:1 Dynamic=8.389:1)

I am leaning towards the first two because they have the smallest of the 4 bores and are also cheaper. The 1052s are copper reusable. Is the 1052 pushing it?

Sonix

iTrader: (1)

.020", +.010" deck height =.030" quench. That's pretty tight. The thing there is once the motor is nice and hot, that gap is taken up from expansion. Anything under .035" ish is kinda "living on the edge". I'd use the .028", a .038" quench is very nice.

head gaskets being thought of as pricey, after spending $$big dinero$$ on everything else sounds kinda funny...

spartyon

How much expansion would there be with a bore 4.140 when the bore of the cylinder is 4.030? That, to me, is a LOT of expanding when dealing with such thin material

Sonix

iTrader: (1)

well no, not the gasket growing. I mean the piston & rod. If they expand a bit in the Z direction, and the main and rod clearances are all taken up on the "upswing" of the piston, things get very close.

1989GTATransAm

iTrader: (3)

I agree with Sonix. Go with the MRG-1134 head gasket.