[The Mad Porter]

I see you had it cat scanned.

Can we see a copy of the lab report?


View attachment 93282

Were you a comedian in another life Mark?









Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
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"Parkland Performance Auto Machine" Formerly RHP
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[The Mad Porter]

Alright, so I thought about it for a few days. But if I'm correct my possible valve to piston clearance issues would be over if I'd use +38cc dished pistons, right? Only problem with dished pistons is my cr is dropping to about 9.3:1, with 74cc heads and 4.300 stroke.

Could get the cr a bit higher with some decking work done, and using some thinner head gasket. This way, the AFR or TrickFlow heads would fit without a doubt. Correct me if I'm wrong.

Compression Ratio Calculator

ENTER YOUR DATA	CALCULATED DATA
Cylinder Head Volume (cc)		Cylinder Head Vol (cubic in.)	4.514
Piston Head Volume (cc)		Piston Head Vol (cubic in.)	2.318
Gasket Thickness (in.)		Swept Volume (cubic in.)	65.086
Gasket Bore (in.)		T.D.C. Volume (cubic in.)	7.484
Cylinder Bore Diameter (in.)		Gasket Volume (cubic in.)	0.652
Deck Clearance (in.) Note: Neg. number above deck, Pos. number below deck		Deck Volume (cubic in.)	0.000
Stroke (in.)		STATIC COMPRESSION RATIO	9.697

A bit of decking off of the heads gets it closer to 10 to 1.

My SCAT rep stated yesterday that Mahle is expected to have the dished stroker pistons available in about 3 weeks.

Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
ParklandAutoMachine.com
R-H-P.biz
"Parkland Performance Auto Machine" Formerly RHP
(253)-988-6648
Log In or Sign Up to View

 

[Mark O'Neal]

Alright, so I thought about it for a few days. But if I'm correct my possible valve to piston clearance issues would be over if I'd use +38cc dished pistons, right? Only problem with dished pistons is my cr is dropping to about 9.3:1, with 74cc heads and 4.300 stroke.

Could get the cr a bit higher with some decking work done, and using some thinner head gasket. This way, the AFR or TrickFlow heads would fit without a doubt. Correct me if I'm wrong.

It's a dish...not a valve relief.

 

[Mark O'Neal]

Were you a comedian in another life Mark?









Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
ParklandAutoMachine.com
R-H-P.biz
"Parkland Performance Auto Machine" Formerly RHP
(253)-988-6648
Log In or Sign Up to View

Not according to my wife.

 

[Colt]

I doubt Scat has a piston for anything other than the factory valve location, outside of custom.

Cookie cutter kits....and all of that.

I know you know more than I do Mark, but scat kits with Mahle pistons can be had with all different flycuts for Cobra heads, Kasse etc. I looked at a Mahle catalogue and they listed a bunch of stroker pistons with asterisks alluding to different head manufacturers. Now covid could have changed a bunch of stuff but I know they did as of 2019.

 

[Mark O'Neal]

What makes you think I know more than you do? Mahle is such a disagreeable company to deal with that I pretty much pretend they don't exist. I have no idea, and do not care, what they have.

Ergo....you know more than I do.

 

[The Mad Porter]

I know you know more than I do Mark, but scat kits with Mahle pistons can be had with all different flycuts for Cobra heads, Kasse etc. I looked at a Mahle catalogue and they listed a bunch of stroker pistons with asterisks alluding to different head manufacturers. Now covid could have changed a bunch of stuff but I know they did as of 2019.

Mahle has one design for std valve location heads and another that covers SCJ / P-51 / AFR.

Nothing for SR71.


I wrote this days ago and neglected to hit post...







Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
ParklandAutoMachine.com
R-H-P.biz
"Parkland Performance Auto Machine" Formerly RHP
(253)-988-6648
Log In or Sign Up to View

 

[Dirk Continental MKIII]

Alright, getting closwr. I did some calculations and sent some e-mails to different manufacturers and came up with this setup:

521 stroker
Scat crank, 4.390 bore 4.300 stroke
Flat top pistons, +6cc valve reliefs
6.800 H beam rods
10.6:1 cr

TFS 78cc heads,
325cc intake runner, 145cc exhaust runner
2.250 intake valve, 1.760 exhaust valve
CNC ported
Headers

Lunati hydraulic flat tappet cam
295/305
245/255@0.050
.615/.622
LSA/ICL: 110/106

Edelbrock RPM air gap intake
Edelbrock 800CFM AVS2 carb

Anybody an idea what kind of power/torque this setup would make on premium pump gas? Should I change anything?

 

[Monstermiler]

Just my opinion and that ain't worth 2 cents. Those cam specs looks like one of those thumper or bootlegger cams that end up sacrificing bottom end torque for a lumping exhaust sound. I think those heads ports are too large and lazy. Valves size is right but the ports are slow.

Scott or Mark would know better but just glancing at the flat tops and 78cc heads it would be more than 10.6 unless you deep in the hole. Five to 10 in the hole and a head gasket to match to keep around 0.050 quench space will make it more pump gas friendly.

Unless you have ever done extensive tuning on old quadrajet carbs before I wouldn't recommend the Edelbrock carbs. Holley style carbs are much easier for a novice tuner.

 

[Mark O'Neal]

Alright, getting closwr. I did some calculations and sent some e-mails to different manufacturers and came up with this setup:

521 stroker
Scat crank, 4.390 bore 4.300 stroke
Flat top pistons, +6cc valve reliefs
6.800 H beam rods
10.6:1 cr

TFS 78cc heads,
325cc intake runner, 145cc exhaust runner
2.250 intake valve, 1.760 exhaust valve
CNC ported
Headers

Lunati hydraulic flat tappet cam
295/305
245/255@0.050
.615/.622
LSA/ICL: 110/106

Edelbrock RPM air gap intake
Edelbrock 800CFM AVS2 carb

Anybody an idea what kind of power/torque this setup would make on premium pump gas? Should I change anything?

It's a 12.0:1 motor with the wrong cam, wrong heads, wrong manifold and an Edelbrock carb (where horsepower goes to die)

I have no idea how much power it will make, but it will detonate itself to death on the first tank of 91.

 

[bob460]

It's a 12.0:1 motor with the wrong cam, wrong heads, wrong manifold and an Edelbrock carb (where horsepower goes to die)

I have no idea how much power it will make, but it will detonate itself to death on the first tank of 91.

BUT.....Mark it's cheaper than what someone can offer from this site............SO it must be right....Lol

Cheers, Bob

 

[Dirk Continental MKIII]

Back to the drawing board. AFR recommended to go with the 280cc runner heads. That would most likely be the 85cc ones, right?

So without decking and the right gasket, that would put it at 10.5:1 cr. Or would it be better to deck it and go with dished pistons?

So let's scrap this cam. What would you recommend on cam specs?

 

[Mark O'Neal]

The 85cc head will get you to 11.5 at .010 deck with a .040 x 4.500 gasket. I don't know if the octane ratings over there are Imperial or Metric (that's "humor"), so I don't really know what you can get away with.

You need to stop guessing and mosey on up to someone that knows what they're doing. The trick is getting all the parts to work together, preferably in the same rpm range. You must go with dished pistons if you want 10.2:1.

 

[rattle_snake]

Another vote to 'pick a knowledgeable vendor' and leverage their extensive experience. Cheaper to get the right combo the first time with help from a pro.

 

[Mark O'Neal]

I nominate Scotty.......

 

[1972Mach1]

Best thing I did when I started to build my first 385 stroker was sit on the phone for an hour or two with A) The guy I got the stroker kit from, and B) the guy I got my custom cam from. Not the same guy and they've both posted on this thread and both have been suggested for you to contact. Do it, be done, and be happy without any guesswork.

 

[wickettoby1]

As I get older I try to lean towards the “buy once cry once” philosophy.
My suggestion is still to find some one knowledgeable enough to build you a shortblock or long block and have it shipped.

 

[tscheerer]

If you haven't already bought stuff, I have a 545 for sale. Used a stroker kit I got on this site with dished pistons for 10.5:1 compression, ported D0VE heads, 260 duration/650 lift roller, etc. Ran 6.70's @ 101 and 10:60's at 127 in an 87 Mustang that was stock body, stock suspension, street legal. Sold the car as a roller and want $3500 for the engine.

 

[Colt]

What makes you think I know more than you do? Mahle is such a disagreeable company to deal with that I pretty much pretend they don't exist. I have no idea, and do not care, what they have.

Ergo....you know more than I do.

Well, I always thought you knew more than I do... bee'n u r a piss ton man u fact er. Reminds me of the guy who said he was an injuneer, just didn't know how to spell it.

It seems Mahle may have pissed on your campfire once or twice.

 

[Dirk Continental MKIII]

Well, thank you all very much for great advice, really appreciate the amount of knowledge on this site. After e-mailing back and forth with Scott, I happened to find a brand new 521 stroker build for sale not so far from my hometown. Seems like its in the right direction with quality parts, suggested by many of you. Decided to buy this one, and finish it myself. For those who are interested, here are the specs:


4.390 bore
4.300 stroke
Scat forged steel crank
Mahle -38cc dish pistons, made for AFR bullits
Forged steel H-beam rods, 6.800
Internally balanced

AFR 280cc 75cc cylinder heads

Voodoo cam hydraulic flat tappet:
adv. dur. 268/276
227/233 @.050
552/564 lift

Steel Roller Rockers

No intake yet
No carb yet
No ignition yet

Around 9.3:1 C/R, so should be pumpgas friendly

If anyone has a suggestion for an intake and carb or to change anything, feel free to comment.