Cadco steel heads

MinnBill

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I've been a registered member for a long time but haven't posted. I've gotten a lot of good information and have collected parts to put together
a 500 engine. The most recent thing was I finally got pro/comp ported heads from Cadco. I had requested flow numbers from the order clerk and
later from the machinist and never got any, so I had one flowed locally a few days ago; done on a 4.625 bore with a 1.75 exh. pipe.
.200 .300 .400 .500 .600 .650 .700
Int 96.7 141 195 240 258 261 267
Exh 78.5 116 151 173 188 192 196

I plugged these numbers into a couple SuperFlow formulas I found. Estimating peak power from airflow came to 499 hp, peak engine speed
from airflow 4800 rpm. I looked on the Stan Weiss site with the ported head flow numbers and I got to say I am disappointed so far. These heads
were in the streamliner? Their catalog showed how thy gradually achieved 525 hp and without these heads? What did I miss? I had hoped to start
with something where I could gradually work toward close to maybe 560-600 hp and now I don't see it happening. Very open to comments and
suggestions.
Might as well dump this while I'm at it. Took 3 1/2 months to get the heads and shipping totaled $350 with the cores.
 

Caddylackn

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Those look more like Pro Street Steel head flow numbers. What type of flow bench? I know those vary a bit.

You are going to have to run well past 4,800 rpm to hit over 560 hp.

I would call Cadco and work with them on this. You should be able to hit your hp goal with their ProComp heads.
 

5one9

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Why a 4.625" bore? From numbers posted on here and other places 267cfm is about stock? 196cfm is better than stock. What valve size are actually in the heads? I'd like to see some pictures of the port work. Intake port and both bowls under the valve.
 

5one9

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Oh by the way, welcome. You are another in a long line of first time posters that nobody on the site appears to see until well after their first post. We're not rude, just out of the loop I guess.................
 

5one9

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Here it is..............and something ain't right.


Cadillac 902 '69 200cc intake /145cc exhaust

.100............200.............300.............400........... .500.......... .600.................700
83/73.....134/107 .... 180/140.......215/164.....248/181......263/191......277/206


Cadillac 493 '75 185cc intake port /124cc exhaust port
2.00 in valve/1.625 ex valve 120cc combustion chamber

.100...........200..............300.............400..............500................600
68/67.......130/97......190/130...... 215/160......233/172........ 246/-turbulant
 

Darius

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Did you write that bore size correctly???
A Cadillac taken out to 4.625 where stock is 4.300???

With stock stroke of 4.304, displacement would be 578.22 CID!!! A 85% engine VE should theoretically = 498.75 HP @ 4800 RPM.

It was my understanding that the largest possible PRACTICAL bore was + .0100. I’m confused.

bro. d
 
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Psychoholic

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That does seem a bit anemic for ported heads? Me confused.
 

Caddylackn

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I would think Cad Company's Pro-Comp heads would be at or over 300 cfm at 0.700 lift.

Could be they sent you their Super Street heads by mistake? Can you send us a photo of the chamber work, and bowl work if you can get the valves out? Just putting in oversize valves doesn't help much unless they unshroud the valves and match the bowl under the valve seat to the larger size. Measure and tell us what size the valves are.
 

MinnBill

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The receipt says "Pro/Comp fully ported small chamber heads. Fastest off the shelf heads available" Valves are measured at 2.25/1.90. Done on a Superflow bench at
a reputable place that builds engines for sale. He said the bore size the ports were flowed on was 4.625 because he didn't have one at 4.3 and the next size was 4.125.
I bought some urethane rubber two-part casting stuff and my thought was to see if I can compare ported and stock. I'll see what I can do about pictures once I get
the heads apart (I might be a little slow on adding pictures). appreciate all the comments.
 

48Austin

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Did you write that bore size correctly???
A Cadillac taken out to 4.625 where stock is 4.300???

With stock stroke of 4.304, displacement would be 578.22 CID!!! A 85% engine VE should theoretically = 498.75 HP @ 4800 RPM.

It was my understanding that the largest possible PRACTICAL bore was + .0100. I’m confused.

bro. d
I was told a few years ago BY CadCo, that the 472/500 could go 120 over before needing block filler. I called them with some things I wanted to do. Told them wanted to go 30 over, they told me to go 60. And said the blocks were good to 120.
 

48Austin

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On the matter of heads. I would pop the extra G. BoogieMan. HP gains off the bat. And potential almost unlimited gains down the road. Almost ready to order myself.
 

MinnBill

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I thought about that. I decided that I didn't want to raise the intake up that high to start, have to cover the valley under the intake, and build a complete
custom exhaust right away (expense was part of it, and I have a set of the short headers I'd like to use, at least to start).
 

Darius

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I was told a few years ago BY CadCo, that the 472/500 could go 120 over before needing block filler. I called them with some things I wanted to do. Told them wanted to go 30 over, they told me to go 60. And said the blocks were good to 120.
THANK YOU!!!

Finally someone else noticed the discrepancy. How in the hell can you have a bore of 4.625, which amounts to 0.325 greater than the stock bore - when the maximum overbore is 0.100 or 0.120 depending on who you ask? That's a full quarter of an inch + another 0.075!

4.300
+.250
+.075
___________
= 4.625

Just sayin'

bro. d
 

5one9

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THANK YOU!!!

Finally someone else noticed the discrepancy. How in the hell can you have a bore of 4.625, which amounts to 0.325 greater than the stock bore - when the maximum overbore is 0.100 or 0.120 depending on who you ask? That's a full quarter of an inch + another 0.075!

4.300
+.250
+.075
___________
= 4.625

Just sayin'

bro. d

I asked why 4.625” in post #3. I figured the answer would be “because that’s what he he had” to which I would have replied “then your results may be correct, try something smaller”. But we never heard back from him. Maybe he’ll sell them cheap as junkers. I do wonder why they wouldn’t give him flow data when he bought them.

Bro. D, check your misprint on post #6. That’s 0.100”, not 0.0100”.

Bro. “Just sayin’ “ Steve
 

5one9

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My Malibu engine is 0.080” over. Felpro gaskets measure 4.36” which is a problem for me. Detroit gaskets measure 4.38”. I figure that maybe was indicative of something about max overbite, but maybe not. Mine are however Copper with an O-ringed block. Copper gasket companies all carry 4.38” and 4.44”. Go figure.
 

MinnBill

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I don't understand what is going on about a 4.625 bore. If you read the posts I stated that the ports were flowed on that size because the next smaller that he had
was 4.125, shrouding the valves. My block is an overbored standard block. Who said anything about my bore being 4.625?? I thought you'd catch your own mistake if
you read it. What discrepancy? If I had gotten flow numbers I never would have bought these. The clerk never sent flow numbers after I asked twice. The machinist stated
they didn't flow them because of the altitude in Albuquerque (he never heard of flow correction I guess). 5one9: after this time and expense "maybe he'll sell them cheap as
junkers" ??? Are you effing serious??? Big help. I just hope no-one gets screwed as bad as I did.
 

MadMax

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My 2 Cents worth: I run a 0.100" overbore, stock stroke 472 = 494 ci. Early set of Boogieman heads, and intake. Intakes ported to get +6% more flow than out of the box. This is in a mini modified tractor puller. Has 6.900" rods, worked Mopar pistons, full roller solid cam, at 14:1 cr, 1250 dominator carb on VP M5 fuel. I turn it 8,000 rpm. Use CadCo ProCad big bore head gaskets. Lots of scrap pieces to get to this point, but it is wild at 8000 rpm - and I am running a regrind obsolete Potter 52 mm cam which could not be reground to the optimum configuration. Lots of learning involved, just too bad Cadillac did not make a canted valve head.
 

MinnBill

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Moot point I guess. Going to send them back and get aluminum. More than I bargained for but I'll have nothing to complain about later. I had thought someone
was using these steel heads or had some flow numbers.
 

Darius

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Mea culpa, mea culpa, It's my fault, I apologize.

It isn’t even my time of the month and the edginess is coming through loud and clear. I am sorry.
With that said, please allow me a brief explanation of where I went wrong.

The first post in this thread mentioned: I had requested flow numbers from the order clerk and later from the machinist and never got any, so I had one flowed locally a few days ago; done on a 4.625 bore with a 1.75 exh. Pipe." My “QUICK” read of that sentence gave me two wrong impressions (both my own) 1, you had purchased something but weren’t getting the information you needed from the vendor, 2, the bore of your engine was 4.625. My bad!

My first thought was, “has this guy been told his engine bore is XXXX and the heads he purchased would flow more than they do?” Wrong assumptions in both cases.

Following posts by others also expressed some uncertainty with the heads, and with that, I keep going on my merry way thinking you had been told / sold a bill of goods! It should be clear that is easy for me to screw things up.

ENOUGH SAID.

I screwed up.

bro. “shamed” d

I'd go to my room but I'm already there.
 
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