Is something up at Scat?

[rumblefish360]

Yeah, but in my opinion, I dont see any real advantage over the 4" stroke, and it also increases rod angle, thrust load on the cylinder and a shorter piston comp height. Most ALL of the stroked sbm builds are cylinder head limited anyway. But again, that's just one guys opinion!

Cylinder head has always been the Achilles heel made worse by huge stroke.

You are the first person to give me a legit answer to that question Everyone acts like 408 over 390 is a MASSIVE difference.. but 408 to 426 doesn't matter at all.. but without much backup as to why.

Thanks

A lot of racers have spoken on the 3.79 being better. I’ve never really seen them explain why but I did take it with a grain of salt since sometimes the racers aspect isn’t the same as the next guy looking for big cubes.

If I'm not mistaken, with the additional stroke to make the 426 sb the rings are up into the wrist pin area, requiring support rails, possibly not ideal for a car that is driven. As @replicaracer43 has stated, less than optimal rod angles, short piston, side loading, and limited cylinder head architecture. If you have ever been in a 408 without W2, W5, Indy, or seriously worked standard port LA heads, they nose over fairly quickly in the high 5, low 6000rpm range. If you add more cubic inches the rpm limitations become more pronounced. Something that can't be measured on a dyno is an engines rate of acceleration, when strokes get very long, engines don't gain rpm as quickly as one with a shorter stroke. Though I don't really race, I've seen at the track where shorter stroke engines can get off the line quicker than some of these really big stroker. I feel the 408 is a nice balance with good heads.

This is the street guy perspective IMO. While there is a advantage to a larger stroke crank for the street guy because there thinking more power to be made at a lower rpm which equals less rpm stress, this also may not be as true as they think. While being accurate, it’s not what most think it’ll be.

I still want to do a 434, or larger. I don’t expect it to be a few things. Things like;
Cheap
Effective
Longevity
Fast in the car because huge cubes isn’t everything.

I do expect a ridiculous amount of tire burning torque even with a numerical low gear set.

 

[rumblefish360]

I would like to see how fast an “all out “ or semi all out 360 could go. Matt ran 6.54 with a stock crank 360, flat top pistons, ported open chamber Edelbrock heads, 727, 4.10 gears, ported victor360 intake but nothing like I’m doing now, 750 alcohol carb, .620 roller cam, and I think he babied it and was shifting at 6400 rpm. Car race ready was 3200 pounds.

Describe your all out or near all out 360.
Personally I think you do well with yours.

 

[dartindanno]

Scat's website says 2-3 weeks out after order is placed

Rotating Assemblies

Rotating Assemblies sold by SCAT Crankshafts, the leader in high-performance engine components for over 50 years.

www.scatcrankshafts.com

 

[pittsburghracer]

Describe your all out or near all out 360.
Personally I think you do well with yours.

Aftermarket forged 360 crank, some light-weight parts, more compression, more racier ring pack, bigger roller cam, more attention and time spent on a Victor340, bigger carb, more rpm, and I know I could do a better set of Edelbrock heads than he ran. The throat isn’t even sized right on those heads as I couldn’t do back then what I can do now. Those heads still have a three anger valve job. With his combo that ran 6.54 what would a good 904 or powerglide be worth over his 727. I Dont use deck plates or vacuum pumps so I’m sure there’s a little horsepower there too.

 

[-Boosted-]

I could have built you one and shipped it to you by now! Still can if you are interested!

Damnit! I wish I had known that. My engine has been at the builder since March and he's had all the parts since the beginning of May..... still waiting on finish machining and assembly.

 

[rumblefish360]

Aftermarket forged 360 crank, some light-weight parts, more compression, more racier ring pack, bigger roller cam, more attention and time spent on a Victor340, bigger carb, more rpm, and I know I could do a better set of Edelbrock heads than he ran. The throat isn’t even sized right on those heads as I couldn’t do back then what I can do now. Those heads still have a three anger valve job. With his combo that ran 6.54 what would a good 904 or powerglide be worth over his 727. I Dont use deck plates or vacuum pumps so I’m sure there’s a little horsepower there too.

Thanks John. 727 vs a 904 has the rep of a tenth, could be more as the power goes up, IDK. I heard a glide takes more power to spin? Not sure if that’s correct. Regardless, it’s now a two speed and a lot has changed that if there is an advantage, it has to be found. I have no idea where to go with that.

 

[rumblefish360]

@Leadfoot - Keep us informed!

 

[j par]

Trying to build a 408 and can't seem to get anything going. My block has been at the machine shop for 1 month and so far nothing has been done. I stopped in 2 weeks ago and asked about the progress, and nothing. They blamed this on Scat and said that Scat wasn't responding. 2 weeks later I stopped in and again they blamed Scat again. I gave them a WTF or two and asked if they were too busy for me. Is something up with Scat, or do I need to find a new machine shop?

Sorry just seen this thread.. Summit as always has the best prices and availability was a little ways out last year... So I just called Scat And ask them about availability and the parts for my kit, And they said they're only waiting on Rods And they had the material, they just needed somebody to make them or have time...
I ordered my own rotating assembly so I don't have to pay the machine shop, mark up.. I just have the machine shop assembled the bottom end and take it from there..
My advice would be to get the part number for the rotating assembly and call Scat and get it from the horse's mouth.

 

[j par]

Cast crank I beem rods and forged pistons. Pre balanced..
Has always been my choice for a street strip...

 

[furrystump]

I got about 1 1/2 tenths out of the typical 727 to 904 swap. It really picked up 2 1/2 but I went aluminum driveshaft, low first gear set and a small bump in flash rpm at the same time.

 

[fishmens67]

@PROSTOCKTOM sells molnar rotating assemblies and usually seems to have stuff ready to ship... should talk to him...