[mpmsmuscle]

72 455 .060 over zero deck height = 474 stroker with 4.25 stroker
4.25 Ohio forged stroker
11.1 compression
Kaufman High port/round port heads. 330cfm
Pro form 850 carb
Northwind 4500 Intake
SD Performance Hyd Roller Old Faithful Cam 236/245 dur @ .0.50 lift 578/582 lift with 1.52 rockers, I will be using 1.65 rockers.
Hooker Super Comp Headers 1 7/8 tube with 3 inch collectors.

Looking for advice on a better Hydralic Roller Cam choice to benefit me with the heads and Intake I am using. Looking for 640 to 650 HP.

Thanks.

[tom s]

For the heads and CI I would go with the Road Paver and 1.65 rockers.Tom

[i82much]

i don’t race and when i work on my car, i break it. but i read a lot, and based in my reading, that cam seems a tad small to me as well.

i have OF in a 10:1 505 with e-heads and a t2, but it seems like the extra compression and northwind are begging for more cam here.

[steve25]

Your hp goals should be able to be be had, but I would only run the 1.65 rockers on the Intake side of the motor.

[Steve C.]

Road Paver

.006- 306 / 314
.050- 246 / 252
.200- 164 / 169
112 LSA
.4000" lobe lift
86 degrees overlap

QXI lobes 13456 / 13459

.006- 299 / 305
.050- 247 / 253
.200- 168 / 174
112 LSA
.3999" lobe lift
78 degrees overlap


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[chuckies76ta]

I would agree. Needs more cam to take advantage of those heads. I made 600hp and 600 t with KRE 300 cfm heads and a torker 2 with road paver cam and a 950 quickfuel. Isn't the 4500 intake a dominator? How are you using an 850 carb on a 4500 intake? Or are you talking about a 4150 Northwind? I would say your in the 700 hp range with dominator stuff.

Charles

[steve25]

The problem is not the duration if you run 1.65 rockers on the intakes, it's the centerline!
It needs to be 108 to 106.

[Gary H]

I agree with most posts above. I'd go with the QXI lobes 13456 / 13459

.006- 299 / 305
.050- 247 / 253
.200- 168 / 174
112 LSA
.3999" lobe lift
78 degrees overlap

Stay with the 112 LSA, much better idle and it won't hurt overall power

[Steve C.]

https://www.compcams.com/16-dual-con...e-springs.html

Keep in mind the High-Port heads have a large diameter heavy valve, typically around 2.200" on the intake. And with a long stem length for a 2.000" installed height.
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[Formulajones]

I think the cam is small for that HP goal.

My guess, if on an honest dyno, you'll probably see 550-580hp, but it will have a nice flat torque curve.

[slowbird]

Originally Posted by steve25

The problem is not the duration if you run 1.65 rockers on the intakes, it's the centerline!
It needs to be 108 to 106.

Can you explain why the centerline is the issue?

[mpmsmuscle]

I'm not sure, but I do know I have the 4500 Northwind Intake, and that the Proform 850 is a square bore flange. I may have to switch carb's.
Which Cam do you think I should use and why? I think the 112 LSA will give me better street manners.

[mpmsmuscle]

Thanks.

[Steve C.]

For interest and with a calculator for entertainment value.....

http://www.wallaceracing.com/calcafhp.php

330 cfm at 28"
474 CID
Typ Street/Strip Eng
8 cylinders

The HP for your Cylinder Head Flow of 330
is 626 with a RPM Range of 5,757 to 7,257
for your engine size of 474 CID

But note it says for better results use total cfm including intake manifold.

That comment about cfm thru the intake is important and relates to an Air Flow Research formula based on cfm air flow. It predicts a normally aspirated engine's horsepower potential based on intake-system airflow.
According to AFR they state it is based on the net cfm airflow delivered at the valve thru the carb, intake manifold and cylinder head. Not the cylinder head cfm flow itself.

In addition, this comment from Tom Vaught in a related conversation on PY...

"Part of the problem is the heads you have were flowed on the KRE bench (which is a pitot tube bench) which does not correlate with a SF bench (Edge Orifice bench) in any way. The formulas work on Edge Orifice flow Benches."



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[ponjohn]

Originally Posted by steve25

Your hp goals should be able to be be had, but I would only run the 1.65 rockers on the Intake side of the motor.

Why is that?

[ponjohn]

Originally Posted by Steve C.

Road Paver

.006- 306 / 314
.050- 246 / 252
.200- 164 / 169
112 LSA
.4000" lobe lift
86 degrees overlap

QXI lobes 13456 / 13459

.006- 299 / 305
.050- 247 / 253
.200- 168 / 174
112 LSA
.3999" lobe lift
78 degrees overlap


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Much quicker ramp on QXI.

[AG]

My RP:
Lobe # Rated duration at 0.050" at 0.200" Lobe lift (in)
3123 300 246 169 0.400
3116 314 252 169 0.400

[Steve C.]

Comp has two similar lobes, 3115 and 3123 here on page 18

https://www.compcams.com/lobe-catalog

Lobe 3115 has 304 and 244 listed as the duration, these numbers are based on a Small Block Chevy journal size. But Dave Bisschop orders the custom cam with lobe 3115B on the intake side. At least to my knowledge that is the norm. It then comes with 306 and 246 degrees duration. This because of the "B' suffix code. Also, in the case of a roller the specs are assuming you are using the same diameter follower as well as base circle unless addressed for in grinding. As I've stated most specs assume a SBC lobe size. If not accounted for during grinding the duration will grow with a larger base circle & be reduced on a "small base" one.

I've been using lobes 3115B and 3116B as used on Ray Klemm's '69 Firebird on the link below and the cam Cliff refers to as the Road Paver, and on copies of cam cards.

https://www.hotrod.com/articles/hppp...9-pontiac-gto/

"Road Paver" Custom Hyd. Roller Cam from SD Performance:
246/252 dur @ .050"
http://www.sdperformance.com/viewPro...productID=1817


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