Another Stroker Cam Question - Kerndog?

[EngineerDoug]

Hey guys,

Asking for some opinions on the Mopar 528 solid cam. I am converging on my 500" stroker build; here are some key points:

Street use only, 3.54 gears, Torqueflite
3800 lb B body
Power brakes
John Cope specified converter, designed for this combination
440 based 500" stroker with aluminum heads
Solid cam
Closed chamber heads, with quench set for 0.045"
Static compression 10:1
Dynamic compression computes to ~7.6:1 using 528 cam

OK so I am pondering the critical combination of cam and compression ratio. Taking a hard look at using the 528 cam with 10:1 compression. What I don't want are detonation issues, crappy/unstable idle, hard starting, or engine vacuum below about 13" in gear.

So my key questions are:

1) Is this cam tame enough to meet my idle/vacuum goal?
2) Pump gas - OK to run 10:1 with this cam?

I know this is a tame build, given the amount of power I could make if I turned up the wick. This is not a daily driver, but if I get stuck in some stoplight to stoplight traffic on a summer day it should not be a headache, either.

Kerndog, I think I have seen your posts about using this cam in your big block? I am particularly interested in your input, as well as anybody else.

Thanks all.

 

[tnfastback]

Just a suggestion. I have a custom ground cam in both my cars which were created by using rear tire size, rear gear ratio, transmission gear ratios, heads, carburetor info, etc. Do some research and you can find someone. They use major cam manufacturers, but re-box in their own packaging.

 

[hunt2elk]

I've heard of several guys really liking that cam with hp exhaust manifolds.

 

[Kern Dog]

I do have that cam in my 440/493. Idle vacuum is great, power brakes work just fine. Rarely ever a hint of detonation and the few times it did ping, I suspected old gasoline to blame. I went back and looked at a few compression ratio calculators and my build was at 11.2 before I pulled the heads and slipped in thicker head gaskets. I am currently at 10.07 to 1 with NO quench! My build isn't optimal but the head gaskets stopped the detonation; a simpler and cheaper option to replacing pistons.
440 .030 over. 4.15 stroke. Edelbrock heads resurfaced a few times with a tested 82 cc volume. .012 deck clearance with 6 cc valve reliefs.
.075 head gaskets. Yeah, .087 quench!

 

[mac]

my build sound the same as yours but 4 speed and no power brakes. i went with 1.6 rocker ratio. also running a 6 bbl. pulling around 14" of vacuum. the big deal for me was getting a proper distributor curve setup. i have it setup to run manifold vacuum instead of ported vacuum. that alone woke this car right up in my situation.

 

[andyf]

10:1 should work but a little less might be safer. A small dish in the piston would allow you to use a thinner head gasket (Cometic has different thickness gaskets so design the engine around one of their gaskets).

The Mopar .528 is a good design but I'm not 100% confident in their manufacturing capabilities anymore so you might want to consider a different vendor. If you already have the MP .528 then use a direct oiling lifter just to give you some extra margin of safety.

You might consider switching over to EFI on that engine, especially if you haven't purchased a carb or distributor yet. A Holley Sniper with a Hyperspark distributor will give you more tuning capability. You'll be able to smooth out the idle and gain idle vacuum with the EFI setup.

 

[66Satellite47]

My 500" EDE RPM 10.5 actual CR motor used a Comp XS 274S 502/511 lift 236/[email protected]. Mild very streetable, ran fine on 92 pump gas. Doesn't make the most power but sure works with a 500" inch motor on the street. A custom with a little more duration & lift would make more power & hurt the tires more.

 

[dvw]

10-1, aluminum heads, newer style chamber, angle plug, quench, decent cam. It may even run on 87 octane. We street drive and race a 10.0-1 440 with Eddy heads, no quench, .557 Mopar solid. It runs flawlessly.
Doug

 

[Burns69RT]

Here’s the thing, with big stroker motors they eat vacuum. Most people just roll with manual disc brakes, I do as well as you feel your breaking. Your power brakes will always be affected when running a stroker with the proper cam. You could always run what you want and run a vacuum canister for your power brakes if you absolutely NEED power brakes. When going to this point there’s a lot of give and take. And between racing and street driving all my cars I rarely care about power brakes. I tend to prefer manual brakes as it’s mor of a driver’s feel and control.

 

[JohnEngland]

my build sound the same as yours but 4 speed and no power brakes. i went with 1.6 rocker ratio. also running a 6 bbl. pulling around 14" of vacuum. the big deal for me was getting a proper distributor curve setup. i have it setup to run manifold vacuum instead of ported vacuum. that alone woke this car right up in my situation.

MAC How much timing is the vacuum advance adding?

 

[mac]

MAC How much timing is the vacuum advance adding?

10 degrees at 14" of vacuum. 16 degrees initial. with engine running 26 degrees at idle. 18 degrees mechanical at 3200 rpm. all in 44 degrees total at cruise.

 

[EngineerDoug]

Thanks for the inputs. I computed 10:1 compression using the 78cc Trick Flow 240 head.

If I went with the 440 Source Stealth heads they have an 80cc chamber, which would drop compression to 9.8:1. If I have to go that way, what do you think of the Stealth heads? I know they are not CNC heads, and I certainly would have them checked before installing them. But since I am going with a relatively mild cam, do you see any problem with stepping down to these heads?

 

[mac]

i would have any head measured for volume. i also use stealth heads and they were different than advertised.

 

[Kern Dog]

MAC How much timing is the vacuum advance adding?

It isn't supposed to add timing at any time other than at part throttle cruise. No timing at idle and none at WOT.

 

[mac]

It isn't supposed to add timing at any time other than at part throttle cruise. No timing at idle and none at WOT.

my vacuum advance is connected to manifold vacuum not ported. so at idle with 14" of vacuum it pulls in 10 degrees. when at WOT or partial the 14" is not produced so the 10 degrees drops out until the system stabilizes.

 

[JohnEngland]

my vacuum advance is connected to manifold vacuum not ported. so at idle with 14" of vacuum it pulls in 10 degrees. when at WOT or partial the 14" is not produced so the 10 degrees drops out until the system stabilizes.

Thanks for the Quick answer.