JakeL

Did some reading through the archives and didn't really find a succint answer. When choosing heads for a 383 stroker, since the bore is the same, are there any additional or different considerations one would make versus choosing heads for a 346?

Are heads that are a good choice for a 346 going to also be a good choice for a 383, or are there additional options or changes that the extra stroke somehow opens up? I imagine valve sizes would have to be the same, since your bore didn't change, but I suppose anything would be possible?

Basically the idea behind this question is that I imagine I'd do heads/cam on the stock motor first, and then plant the heads on top of a 383 and a slightly bigger cam when the time comes, if that is a good idea.

-Jake

2001 Pewter WS6

iTrader: (43)

I have a set of Absolute Speed Stage 2.5's. They have 2.055 intake valves and 1.60 exhaust valves. They flow 320+ and make great power. See the sig

JakeL

Looks like they do the job. Would those heads also be usable on a 346? If not, what is the difference I don't know about? Valve sizing?

-Jake

2001 Pewter WS6

iTrader: (43)

You could go with the 2.02's with no problems. Call Jay and see what he says. He has a 346 putting down almost 445rwhp in an A4. This is with a G5X3 cam but it would still make 425 with a TR224. Tell him Mark told you to call... Decide which cam you want to go with before you get the heads. The springs have to match the cam and he will port the heads for a specific cam.

Mike K.

I was thinking the same thing, I am wanting to get a stroker but If I have to by new heads thats another 2k on top of the crank rods and pistons. My heads are milled .030 and they are the 5.7 ltr kind. I know that my compression should be higher when going to the larger stroke but couldn't I get some reverse dome pistons to lower it back down?

JakeL

Mike - with your heads milled 0.030, what is your compression now? To save a buck, I was thinking about putting Patriot's perimeter Stage II LS1's on my car, and milling them 0.030 (seems to be the max allowed), to try and bump the compression up closer to the level of the 5.3 heads.

Yes, dished pistons would help you lower your compression back to a level where you'd want it.

Everybody else: would such heads (Stage II 5.7 heads) on top of a 383 be decent, or would that result in a serious lack of breathing for such a large motor?

My tentative cam choice for the 346 is in the 220 to 224 on 114 range, and from what I've read, seems like the 5.7's would be a decent match for those selections. I wouldn't go all that much larger on the 383 either - probably no more than 230, based on what I've read, and heard, about idle quality here.

-Jake

Mike K.

My compression is about 10.5 to 1 talking into account my valve reliefs. If I can use my 5.7 heads on a stroker I will be inclined to get a stroker but I don't want to get a half assed setup.

strokedls1

iTrader: (1)

I would go with some stage 2 with 2.055 1.60 valves. I used that size valve on my 346 h/c, and am still using them on a 422. They would work good on a 382.

JakeL

seems like I see 2.02 and 1.57 as common valve sizes (quick look through Patriot and a few other sites). Any reason that folks don't normally go to the 2.055/1.60 sizing on the stock bore size? (the 2.055 seems to be a stage III/large bore head thing, which doesn't seem to make sense for a stock bore engine?)

-Jake

jyeager

It's difficult to pick either heads or cam that are good for both a stock bottom end and a stroked one. If you need to increase power now and want to stroke it later then the best you can do is get a set of heads that have the desired flow now and can still be increased more (by extra porting) later. For instance, AFR's new heads out of the box for the 346 and have them hogged out a bit when you stroke it.
The problem is that you have one specific port size that is ideal for any given displacement. If the head is good for the stroked motor, then you've got slow charge velocity on the 346. If it's ideal for the 346 then it's choked on the 383. Don't even think about using the same cam in the two different combos. Unless you are very free with your money, there are 2 things that might be advisable.
1. Save up and do it all at once. This is the least total cash outlay but you are stuck with a stock motor longer.
2. Do heads/cam now and sell them when you stroke the motor and get new heads/cam. This costs a bit more but it helps to sell your old stuff. In the meantime you've got a stronger 346.

JakeL

I was afraid that might be the case, but thought I might ask anyhow.

I assumed the cam had to change, but wondered if the heads might work ideally in both cases, but I don't think it's worth the compromise on both ends, sounds like.

Appreciate the advice everybody!

-Jake