Optimizing my 461 set up ( OF Cam , SP and SD heads)
 

While running my business, doing renos at my shop and keeping the toys in running order, I barely found time to work on my new engine for the 73 bird. Like most of you, I hate to do things twice and prefer to gather intel before pulling the trigger.

So here is what I plan on doing with the '73 that currently drives real nice with a built 350P, 670 heads, 1968 Iron 4 barrel intake, 800cfm Qjet and Hooker 1 5/8 headers. Th350 little stall converter and a 1968 4 pinion HD 3.36 diff fitted to the second gen.

The new heart for the car is:
A 1970 400 2 Bolt studded mains zero deck
6.8" Forged rods
Ross forged flat tops ( 8cc valve relief)
Forged crank 4.25 stroke
CR is at 9.5 using thin cometic (.028)
Holley street dominator Intake ( SD Dave still has my '71 HO intake)
800 CFM Qjet
Mallory Unilite with Vacuum adv.
Dougs 1 3/4" 3" coated Headers
Heads are SD CNC ported #46 irons with flow chart attached ( Springs and installed height with be changed for the cam)

Now for cam I really wanted to use the original Old faithful from Dave ( which I have in stock) but I am second guessing myself ( maybe not enough CR, rear gears, headflow CFM)...
So I found here a baby HR from KRE ( 232-238) that may work with my Solid lifters I planned on running on the OF ( Cam cards attached )

The car is a 1973 Esprit, along with the 461 engine swap, its also getting a new drivetrain and fuel system to feed the engine and Nitrous system (200 shot)

Jakes Performance Transmission TH400
Continental P1D PS Balloon plated "3200" stalled 10" converter
3.08 Posi 8.5" 10 bolt. diff
245 60 15 tires all around
Bilstein suspension and subframe connectors
2.5" transverse H piped exhaust system but I have a Pypes Full 3" with X pipe with Borla XS and 3" tailpipes I could use for this car if needed for max potential.

Engine ( rings and gap), fuel system (stand alone) and transmission are built to deal with a regular 175-200 nitrous shot in mind (plate).

The car is not a race car but will see quite a bit of local semi serious street racing duty while my LS7 BBC Camaro is getting its refresh next summer.

What you guys think?

What Cam would you run ?
( the smaller 232-238 KRE HR would most likely get 1.65 HS Rockers, but will use 1.5s if I end up using the Old faithful.

How would you optimize this set up?


Peter

I’d run OF with 1.5’s.

I would run the 51-000-9 cam

2X Steve.Tom

Lots of live for the OF cam, seems like despite my lowish 9.5 CR and 3 08 gears its still the popular one.l so far.

Peter

Lots of love for the OF cam, seems like despite my low-ish 9.5 CR and 3 08 gears its still the popular one so far, at least I wont have to swap the cam if I ever swap the CNC ported irons for a set of D port aluminum heads in the future.

Peter

There is one problem that I see.

Those 995 valve springs are rated to only .550” lift, so I would look at swapping over to a Crower 68405 spring which is good to .600” lift.

Indeed Steve that was the plan, that why I mention it in my first post, also the fact that Ill be running solids Ill need a little more seat pressure than withe squishy lifters as well .

Peter

One thing I noticed, you said you will run a .028 head gasket. If you zero deck it those pistons may be a little close to the heads. Running a .028 head gasket you will want to put the pistons below deck but loose some efficiency doing that. You might consider milling the heads to get your compression up, zero deck and .040 head gasket.

Regarding spring pressure with the Old Faithful cam. Statement by Dave Bisschop here on PY in June 2015:

"In most applications we use the Crane 99893 valve spring, installed at 1.790-1.810", I set the intakes on the tighter side of the tolerance, I test all the springs and always put the ones with the higher pressures on the intake valves, since the intake valves weigh more and also have the momentum of the charge pushing on the back side of the valve while the exhaust valve if anything has pressure pushing or drawing it closed and the valve is lighter. On my digital InterComp spring tester the seat pressures on a new set of springs will range from 147-157lbs typically @ 1.800" and 380-390lbs @ 1.200" open pressure."

Note: It is my understanding the 99893 spring is no longer used. Last I heard he was using the Comp 26925 spring rated 141 @ 1.180"
I believe coil bind on that spring is rated at 1.100"

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Note,if running solid roller you should run about 200 on the seats,also you will loose lift based on your lash(6 thou)recommended so about 9 thou lift with 1.50s,also about 8 degree duration.From Dean Harvey at Comp.Tom

X2


https://forums.maxperformanceinc.com...s+Faithful+cam





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I just have an visceral hate for squishy aftermarket lifters unless they are stock units like in my modern stuff, I just prefer to run solids, all my old iron is running either solid FT or Roller.

With Iron heads you dont have to lash much as well.

Peter

I will suggest if you are going to consider the use of the Crower 68405 spring with a solid roller lifter that you evaluate your specific situation very carefully.

And for sure take Crowers published spring pressure numbers with a grain of salt. Test the pressure at your verified installed height in use with their retainers in place.

Example, on a set of those springs tested at 1.687" installed height they were only 115 lbs seat pressure.

In addition with that spring you will need to evaluate your distance from coil bind ! !

I have a friend that bought a 71 Chevrolet C-10 pickup, I have a couple similar.
He had been looking, I helped him find one.

The 71 had goofy starting problems. It would run and start fine one day, next day it woulf spin and nor fire.

I went though everything electrical. Problem was the Unilite dist.
I guess the ionized air under the cap had allowed funny things to go on there.
There was a small piece of something the formed over the electrical eye on the dist. base (where points would be inside cap). Looked like a patch of cob web, it was on the eye. It was only attached at one spot on the perimeter of the light. This patch of crap would apparently blow open and closed. His pickup would run perfect for a while, then not!
I had the dist out of the engine, thought abought just cleaning up the module (the electric eye is part of it). BUT I had new module, decided to install it while apart...

It ran perfect for several months. Then it laid down again!!! I checked everything, The culprit was the dist.

My buddy told me to just get a good, new dist. I bought a new HEI (from O'Reillys)

No more problems, NO Unilites for me!!!

Jeff, did the C-10 engine have a old faithful cam :)


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LOL, a bone stock olden GM Target Master engine. Runs quite sell!!!

Now back to our original program 🤣

"Now back to our original program"

With post number 14



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the 51-000-11 cam will make more compression because of less overlap.
My 7:8:1 motor sounded a lot more healthy with a cam like yours.

GT