Stroker Qs

[T-rex]

Sorry guys, more questions. I've made the decision that when I get a work car I'll pull the 304 out and put the stroker together myself because I'm capable of that and it'll save me bucks on being built, but I know little about getting figures with engines so I was looking at 230rwkw (wanna keep it pretty simple) as a base but gunning for lower down torque. I was looking at this kit

Holden 304-308 5L - Scat 355 V8 stroker engine kit | eBay

with the 10:1 comp pistons, 30thou over
I already have a torque power dual plane
750cfm throttle body (would be getting a tad restrictive I imagine)

But I dont know what type of cam to go for (I don't understand LSA etc) but I would say something like a 284, with revs around 2200 to mid/high 5000, I also want to leave the heads alone flow wise seeing as reading up on it people think that they flow alright unless your chasing big power. I know this is a pretty loose question but am I in the right ballpark? Otherwise I'm open to suggestions.

Cheers

[Brendo169]

i put a lunati cam in my 355 but its running stock manifold. its an incredible cam for low down power...its pretty much a crane 286 with .005 more lift on both exhaust and intake

[mangzilla]

off topic, but are those stroker kits all youd need to rebuild a 304 into a 355?

[VSSS_5L]

Is 1500 bucks what you'd expect to pay for a stroker kit for a 5l? It seems...cheap...achievable...easy...awesome.

[T-rex]

Cheers brendo, I'll have a look into that. It'll make it a 355 but you need re new some other bits but basically yeah, it'll have pretty much all the stuff for the bottom end which you'll be swapping around as far as I can tell. And for the price thats why I asked because, it seems pretty good and its pretty realistic because its not forged or anything, I think the forged kit is like 2200ish, I just need to know whether it will help me achieve what I'm after and whether or not it'll last.

[ari666]

still need to balance it.

230rwkw is a big ask. you may scoff at the numbers, but its still a not a walk in the park.

[T-rex]

Yeah I know I need to still balance it, is their balance all I need as in can I then just put it in so to speak. Fair enough on the numbers I wasn't sure on how much it would make but what would I be looking at and how would the torque be as opposed to kw. But is it a good kit to build with? And will the torque/power mainly be decided by the cam/manifold?

[Brendo169]

the torque and power will be mostly decided by cam, compression ratio and head work i would have thought...those things with a good manifold and free flowing exhaust

[T-rex]

Cheers man, the main thing I'm struggling with is whether the kit is a good foundation to build with, I don't want it to be a slug engine because the kits no good. I would imagine with it being SCAT and being 10:1 it will be alright but I don't know.

[Brendo169]

yeah you will be fine. a lot of people on this forum are running scat cranks including me!

[ari666]

from all i have read, scat are the brand to go for for holdens.

but have had no actual expierence with them.

[T-rex]

*Takes deep breath* I'll double check when my block was made to see if it will need machining (VS block shouldn't because of the 215i option, correct?) because its a GM replacement then if thats at the right date I'll get the kit I reckon. Then I'll have a long hard think about the cam.

[ari666]

you can machine it yourself to fit. it isnt that hard.

[T-rex]

Yeah I know, who am I kidding I was gonna get the kit anyway.

[VSSS_5L]

Im halfway through doing my heads and replacing all the gaskets and junk chasing an oil disappearing act. I'm kind of hoping...kind of that when it all goes back together that it still uses oil and that it needs rebuilding so i can go out and buy me a 355 stroker kit, I've already played out the convo with my missus in my head a few times... "Weeell... The normal rebuild kit is like...700-800 bucks anyway...So like...if im gonna spend the money i might as well spend a little bit more and get the stroker kit.

I'm pretty manipulative, i reckon i can convince her it was her idea for me to get a stroker kit.

[Darren_L]

my 304 with 227/220 113 LSA cam, flat tops & stock heads is making 206rwkw, I can't see 230rwkw being out of the question for a 355 with the combo you are planning on

[T-rex]

Thats good to hear, I just noticed though it says 10:1 with 58cc heads, how is that achieved because I started trying to search it and it seems 64cc is the size of stock VN heads? So that would drop the compression ratio if I just put it together as is wouldn't it?

Having a retarded stab at using the comp ratio calculator, it would seem I would need the flat tops to get to 10:4ish, but I don't know the head gasket thickness or deck clearance so I used what was already in there from where I got the link (not quite right but would be close), anyone know whether I'm on the right track there or way off?

http://www.csgnetwork.com/compcalc.html

[T-rex]

Silly question what is deck height? I can't find any real description.

[VR38]

Relation between top of piston and top of block at TDC ie, piston top sits 1mm down top of block at TDC is 040th (approx) deck height.

[T-rex]

Ah thanks, so really I wouldn't be able to tell what the deck height will be without the kit in hand, but I would have to assume that the kit would be designed to achieve the the desired CR without mention of the deck height assuming it would be left standard?

The people who sell the kit just got back to me about the pistons, he said it would have about 10.22:1 with the hyperuetectic's (standard option I didn't notice) which have an 8cc dish with a 61cc chamber but that CR would be below 10 if my heads are at the proper 64ish there supposed to be. This is way harder than I initially thought.

[VR38]

Ah thanks, so really I wouldn't be able to tell what the deck height will be without the kit in hand, but I would have to assume that the kit would be designed to achieve the the desired CR without mention of the deck height assuming it would be left standard?

Yes, he can only assume you will build it to 10.22, that's what building a motor is all about, the thickness of the head gasket, how much the heads and block have been milled, combustion chamber size etc etc, all these things are variable, along with the type and shape of piston in the chamber area.

You were probably quoted 10.22 on the assumption 040tho head gasket, 040tho deck height and standard holden chamber but this is only a gestimate just as i assume is his, untill it is dummy assembled and measured you will have no idea really IMO.

[Blown V6 Hatch]

To get the comp up to what he said, it would have to be 0 deck height.

A 355 with the following

0.030 overbore (obviously)
0.040 head gasket
0 deck height
8cc valve relief
60cc combustion chamber

will give about 10.2:1

If you use the stock heads (64cc chamber) that will drop to about 9.8:1.

[T-rex]

Thanks guys, so it looks like no matter what I'll have to get the top of the block machined to adjust deck height (correct or way off?) and in simple terms shave the heads (same again?) to get the CR in the right area? Although if I was to use standard heads with 0 deck, with all the other measurements and the flat tops with 5cc reliefs using the calculator it gives me 10.2:1, could that work instead with only the deck height needing changing?

[Blown V6 Hatch]

Yes, you will need to get the blocked decked to achieve the desired deck height. You will need to dummy up the crank, rods and pistons first to see how much needs to be taken off the decks to achieve 0, then have it decked. Yes, You could use a piston with a 5cc valve relief to get the comp up and leave the heads stock.

[T-rex]

Cheers mate, that helps heaps. So I would get the flats and make adjustments as necessary, I assume the difference that makes them flat tops is that there is only 5cc worth of relief making them pretty much flat, just wanna double check so theres no unwanted surprises.