[pastry_chef]

Originally Posted by Skip Fix

Harold Brookshire Ultradyne cams and did work for Lunati, Comp would change cam splits depending on E/I ratio. John Angeles on his RAIV SS car he has run for decades has a single pattern cam also.

I remember Harold's comments on splits.

I admire the method Mike Jones uses, also looking at valve size, VE and RPM (time). He does not use any relative comparison to the intake lobe as a guide. I think valve size is very key.

I recall him mentioning speed of sound in the calcs and so exhaust temp will come into play there. I have my own chained equations based from his comments and things others have shared over the years. It does give me very reasonable lobe / valve area but nailing the VE input is obviously tricky. Ever a work in progress.. maybe one day.

CamKing wrote: ↑ 04, 2016 11:50 am
First I calculate the amount of mass in the cylinder at the max RPM you want
to make power at, then I use the exhaust valve size, and exhaust port flow
to calculate the "effective" choke diameter of the exhaust port, then
calculate how much time(duration) that effective choke diameter will need
to evacuate the mass in the cylinder.

Mike Jones comment

I calculate the total time needed(duration) to evacuate the mass at peak RPM, then focus on closing the exhaust valve at the point the pressure below the exhaust valve equals the pressure above the intake valve. When I know the Exhaust closing point, and duration, I know what the exhaust opening point is.

[Half-Inch Stud]

Ram Air II heads, what i think for Performance with Retained Value;

No touching the Exhaust side! No Exterior mods. No Milling.
ValveCover: Cut Guide Bosses to .550"/.530", not .500" for Positive seals, use hardened Spring seats. Use 1-piece Valves, larger angle Retainers/Keepers.
Combustion Chamber: no mods. I unshroud Intake Valve lightly near Head Gasket divider (455+060)
Intake Bowl: Lightly blend Seat ID into Short Turn.
Intake Runner: Grind Pushrod Buldge modestly, widen runner, decrease corner radiuses.
I went to tall-port with eye on Cross-Sectional Area uniformity, but you may not want to.

Mine did not need valveguides, maybe yours don't either. Got no advice on press-in guides.

[Half-Inch Stud]

Cams: Figure that Cam Lobes have Slow, Medium, Fast Ramps:

if ADV - 050" Duration is < 45 that is a fast ramp; probably gonba ping with Iron Headds, 4000 rpm feels like 6000 rpm thus needing more spring pressure, hard on lobes, etc. compare "Extreme Enery" cams with any other. Voodoo might have Fast Libes.

If ADV - 050" is > 55 that is a slow ramp: great ping-free performance with Iron Heads, easy on Cam Lobes, over-rev has great margin without damage.

I do not see the need for Roller cam for Performance. ONLY Reliable Rollers are if the Lobe liift is low, like 0.3" ( not 0.442" range like my dust collector )

[Verdoro 68]

Got my first batch of parts yesterday. I have to say, I was expecting the worst with the repro RA IV manifold based on previous comments. The ports need work, but overall there's plenty to work with and it doesn't look like anything is dramatically mismatched. My machinist might have a different opinion when he gets his hands on it

It came with SCE gaskets, so those are the outlines you see.

[Verdoro 68]

Exhaust manifolds came in from Ames too. I'm not sure who makes them, but they seem just fine.

I'll wait to order a cam until I can get the engine out and ensure the bottom end is in good shape. The machine shop can't take my heads for another few weeks so progress will be slow.

[PAUL K]

Originally Posted by Verdoro 68

Got my first batch of parts yesterday. I have to say, I was expecting the worst with the repro RA IV manifold based on previous comments. The ports need work, but overall there's plenty to work with and it doesn't look like anything is dramatically mismatched. My machinist might have a different opinion when he gets his hands on it

It came with SCE gaskets, so those are the outlines you see.

Looks like they might line up pretty good with these untouched RAIV heads.

[Verdoro 68]

Originally Posted by PAUL K

Looks like they might line up pretty good with these untouched RAIV heads.

IIRC, you had a hand in creating these manifolds, correct?

When I get a minute I'll see how they line up to my heads.

[PAUL K]

Originally Posted by Verdoro 68

IIRC, you had a hand in creating these manifolds, correct?

When I get a minute I'll see how they line up to my heads.

That is correct Sir, time constraints and a pretty crappy (port alignment) 1972 HO manifold really hurt the finished product.

[Verdoro 68]

I appreciate your contributions to the hobby! If this all works out, I’ll have some cool stuff under the hood.

[Skip Fix]

The intake looks better than the RAIV repop I got. Had to sent the first one back then some weld on the second one.

[grandam1979]

I think SD was charging extra to do the repop intakes because of core shift and welding needed to port properly. That one does look better than some I have seen.

[Verdoro 68]

They were, but according to their site they stopped porting them.

["QUICK-SILVER"]

Before you do any intake grinding... Get your heads sitting on the block and check intake fit/port alignment. That would be forwards, backwards and up/down for both sides.

Clay

[Verdoro 68]

Circling back on this build now that I've got the engine out and apart.

I have the valvetrain and cam parts on the way from Kauffmann and have been putting together my shopping list for the remaining odds and ends.

Regarding head gaskets, I've traditionally used the plain old FelPro 8518 but I see there are a few other options out there. For my build, is there any benefit to using FelPro 1016 or the Butler head gasket?

[PAUL K]

Looks great!

[Verdoro 68]

Lots of work to do still but it's fun to be able to pop all the parts onto the block for motivation. The intake appears to fit really nicely. Bolt holes line up, ports are generally there. Other than gasket matching, the crossover heat shielding needs some minor finessing but overall the intake fits way better than I was expecting!

I'll be running the Kauffmann's HR 224 cam with 1.5 roller rockers based on Jeff's recommendation.

Adv. duration 278/289
.050 duration 224/230
Lobe sep. 112
.502/.510 lift w/1.5 rocker

[Formulajones]

Intake looks exactly like mine did when I bought it 5-6 years ago. It's worked perfectly since. I wouldn't worry too much about it. Do a mild gasket match if you wish and run with it.

[PAUL K]

Originally Posted by Verdoro 68

Lots of work to do still but it's fun to be able to pop all the parts onto the block for motivation. The intake appears to fit really nicely. Bolt holes line up, ports are generally there. Other than gasket matching, the crossover heat shielding needs some minor finessing but overall the intake fits way better than I was expecting!

I'll be running the Kauffmann's HR 224 cam with 1.5 roller rockers based on Jeff's recommendation.

Adv. duration 278/289
.050 duration 224/230
Lobe sep. 112
.502/.510 lift w/1.5 rocker

That will be a fun engine! Are you going to coat the exhaust manifolds?

[Half-Inch Stud]

Originally Posted by PAUL K

That will be a fun engine! Are you going to coat the exhaust manifolds?

Ditto. My PMD Driver Roundport got Hi-Temp primer, then Hi-Temp White (both water-based). So am curious to the better Do-at-home coatings.

[Formulajones]

Just an FYI, I use the POR-15 cast grey exhaust coating and it holds up fantastic.

Just apply with a brush, doesn't get any easier. I've had a couple of my own sets of manifolds done for several years now and they still look like the day I coated them, and they are daily driven. So I've been using it on customer cars and they have all been very happy.

A small pint can will do 4-5 sets of manifolds too, so you don't need much. I just put the manifolds in the blast cabinet with glass bead and give them a light dusting and apply coating directly to the manifolds with a small brush.