355 rotating assembly

[STOKESY77]

Hi all,

I'm putting together a 355 build and was after your opinion on the rotating assembly parts I'm thinking of using -

Crank - Scat 9000 series 355 with Holden journal part # SC930834805627

Rods - Scat Pro Sport forged H-Beam 5.627" part # SC230856272124

Pistons - SRP forged flat tops 4.030" 0cc part # SRP311080

Just wanted to know if you think this combo will balance up nicely without any mallory added.

Thanks in advance, STOKESY77

[EH179]

Not knowing the total bobweights, i will say you should be fine, maybe a bit of lightening, if anything.

[STOKESY77]

Yeah a bit new to the 355 thing and just want to go with a setup that works and balances up well. Whats everyone's thoughts on Chev or Holden journal SCAT 355 cranks? I have heard Holden journal balances up easier.

Cheers, STOKESY77.

[Horaldic]

Holden journal is nicer/easier to balance.

Also I’ve now heard two reports of people needing to remove what I’d consider an excessive amount of material to clearance the blocks with newer chev journal 355 cranks.

One reason many people feel drawn to the chev journal cranks is that they see a lot more “choice” in rods when they search through catalogs and they tend to be cheaper. This isn’t actually so much the case with Holden blocks as it might first appear because only a smaller subset of those rods actually suit a Holden block “out of the box”.

[Smitty2]

I am running SRP +20 forged flat tops in my latest build race engine

my engine guy likes them .. as when on an ex-Perkins set of A9L spike rods
the weight diff of each assembly was less than 20gms between lightest to heaviest
.. not much work at all to make them the same he said

With a 7kg steel flywheel, std stroke 304 crank and race balancer, it was mentioned
that this was 'a nice easy balance job' when I collected it from the shop

[46Crab]

I’ve used a SCAT Chev journal crank (older style) with 6” SCAT I Beam rods (7/16 bolt versions) and SRP Professional Pistons (1.125 pin height) and they balanced up well no with Mallory slugs required.
It revs up quickly and due to the lighter components doesn’t beat up the 2 bolts mains. Yes it runs ARP studs in the bottom end.

I’m also currently building another 355 stroker for my brother using the same type of SCAT crank and SCAT 6” I beam rods but with Wiseco pistons.
I’ll report back on the bob weights and how it balanced up when it’s complete.

[STOKESY77]

46Crab what were the part numbers for all the components you used, crank, rods & pistons.

[46Crab]

I’ve used a SCAT Chev journal crank (older style) with 6” SCAT I Beam rods (7/16 bolt versions) and SRP Professional Pistons (1.125 pin height) and they balanced up well no with Mallory slugs required.
It revs up quickly and due to the lighter components doesn’t beat up the 2 bolts mains. Yes it runs ARP studs in the bottom end.

I’m also currently building another 355 stroker for my brother using the same type of SCAT crank and SCAT 6” I beam rods but with Wiseco pistons.
I’ll report back on the bob weights and how it balanced up when it’s complete.

[IMG]https://uploads.tapatalk-cdn.com/20201103/66ce1f6b25c2bf5fc07d089845dca97a.jpg[/IMG]
Conrods
[IMG]https://uploads.tapatalk-cdn.com/20201103/0505c7b5c4f9215ab17b08ac665d9f97.jpg[/IMG]
Crank

[IMG]https://uploads.tapatalk-cdn.com/20201103/9824c112d5ae9a4d5c6122017e1d3311.jpg[/IMG]
SRP Pistons in my current 355

[IMG]https://uploads.tapatalk-cdn.com/20201103/88d20fb504511df3a6f85266a1e3c9c0.jpg[/IMG]
Pistons going in my brothers engine using same crank & rods.

[STOKESY77]

[IMG]https://uploads.tapatalk-cdn.com/20201103/66ce1f6b25c2bf5fc07d089845dca97a.jpg[/IMG]
Conrods
[IMG]https://uploads.tapatalk-cdn.com/20201103/0505c7b5c4f9215ab17b08ac665d9f97.jpg[/IMG]
Crank

[IMG]https://uploads.tapatalk-cdn.com/20201103/9824c112d5ae9a4d5c6122017e1d3311.jpg[/IMG]
SRP Pistons in my current 355

[IMG]https://uploads.tapatalk-cdn.com/20201103/88d20fb504511df3a6f85266a1e3c9c0.jpg[/IMG]
Pistons going in my brothers engine using same crank & rods.

Thanks 46Crab, I like the sound of your set up nice and light but revs up good. Should go good with the rest of my set up. VS factory clearanced block zero decked with TK's oiling mods, reconditioned VS heads with .020" shaved with larger Ferrea 6000 series stainless valves and pocket port, Harrop single plain hirise, Crane F280 solid cam, ASR hi volume sump & pick up, Pavtek main stud girdle with ARP studs, COME blueprinted and prepped oil pump. Looking for around 10.5:1 compression. Don't know what carby yet but was thinking Proform 780cfm and should I go aftermarket dizzy or stick with stock Bosch set up?

[46Crab]

STOKESY, sounds like you are on track to have a pretty good combo there. I like the 280 Crane for a real street car. Mine still puts a smile on my face when I drive it, it goes well, sounds tuff and makes all the right noises.
A well set up (it will need re-graphing) factory Bosch HEI ignition will fire that combo fine or you can go down the path of an MSD set up depending on budget and what else you are using the car for.
I don’t know much about the carby you mentioned but TK did a set of heads for me recently and we were talking new carbys for a 355 (475-500hp) and he mentioned he has used a few Quick Fuel Brawler carbs (750 double pumper race version with billet base & metering blocks & HP body) and reckons they are good bang for buck and don’t need much work out of the box.

Anyway food for thought, keep us posted on how this engine progresses.

[STOKESY77]

Cheers Crab, will do. Yeah I might have to check out them qft brawler carbs, I already use a qft 600 vac sec on the mild 308 and it's good for what it is. The 355 I'm doing is just a weekend warrior street/strip thing not an everyday thing even though I wish it was 😎

[TK383]

My go to rotating assembly for up to 550hp is:
Scat chev journal crank
Scat 6" pro I beam rods
Srp pro true flat top pistons.
Romac race balancer

[46Crab]

My go to rotating assembly for up to 550hp is:
Scat chev journal crank
Scat 6" pro I beam rods
Srp pro true flat top pistons.
Romac race balancer

Thanks for chiming in Tony, always good to draw on your wealth of motor magic knowledge.

[STOKESY77]

My go to rotating assembly for up to 550hp is:
Scat chev journal crank
Scat 6" pro I beam rods
Srp pro true flat top pistons.
Romac race balancer

Hi TK,

Any part # for those rods & pistons?

Cheers, STOKESY.

[46Crab]

Hi TK,

Any part # for those rods & pistons?

Cheers, STOKESY.

I’d just about bet my balls TK is using the same crank and rods I am, just different pistons.