Hey, I am in the process of wanting to build my 350 one piece to a 355, I was looking at summit and found this:

http://store.summitracing.com/partde...3&autoview=sku

The block is in great shape, will be upgrading heads at a later time but for now will be using the vette heads 10088113 but I am a little worried about compression. As far as they go they will be ported to the max for the miniram to go on top of it. Any suggestions?

 

Do you need to replace the crank and rods?

 

Nope, not needed to replace crank and rods, but just as an example of what to look for in case. It was a perfectly good running 350, but I would rather have a little more kick. It has no ridges at the top of the cyclinder bores, cant catch a fingernail on it if I tried.

 

You won't get any real kick by changing from a 350 to a 355, all else equal. If you want kick, do heads and cam, maybe compression depending on where you're at now.

 

You don't "rebuild a 350 to a 355". Boring it out .030" doesn't create some whole new engine size, even though it does add inches; it's just some maintenance.

That said, it's just about senseless to buy a whole new rotating assembly if you don't really "need" it anyway, and leave it as a 350 (whether standard or some overbore). Especially not that "budget" "entry level" one. It offers little benefit over re-using your stock stuff. Basically, zero bang for the buck, if your stock crank & rods are still OK.

IMO neither that one nor the stock stuff is enough to withstand all that can be obtained with the MiniRam.

You would be better served by going with the "ESP" series, and upping your inches to a 383, if you're going to replace the rotating assembly at all. Either leave it as it now is, or go for the jugular. I'd suggest the 12108 assembly, get your block zero-decked to it, and run a cam in the 230-236° @ .050" intake range, set up for high RPM (i.e. not the most aggressive possible ramps).

 

The cam I have already selected is the XR276HR-12, 224/230 and will be bought as the whole kit. What I am unsure of would be the compression with the 113 heads, since thats what I got to work with. If it were up to me I would have been better off saving for the AFR 195 heads instead of the 113s that I have now (thats with the 383, compression will be 10.5 to 1 with 350). But I can save them for a future project.

So its either 350 or 383 eh? I was thinking that a 355 is (or was) a 350 block bored 0.030 over but now know its not worth the effort. Can you point me in the right direction?

 

A 355 is a 350 bored .030 over, but boring isn't done for performance. It's done to clean up the wear on the cylinder walls.

 

Well then I will stick with my original plan, build up the 350 with the miniram, with the 113 vette heads and the xr276 cam kit. After that though.....383...
Hoping for 400HP at the flywheel.

 

Higher RPM you *don't* want the most aggressive possible ramps? Does that hurt your RPM capability somehow?

 

Sure you can run aggressive ramps, then you have to run aggressive valve springs...

 

They will be coming with the beehive 986-16 valve springs that come with the kit, also comes with a single roller timing chain but I would rather go with the double roller. If the 113 heads are fully ported and polished with the XR276HR-12 cam do ya think 400HP at the flywheel is attainable?

 

986's aren't beehives, just an FYI.

Sure 400 is possible. Depends a lot on how aggressivly the heads are ported, though.

 

The only main thing that bothered me was how tight of a quench it was, but it shouldn't be a problem. A lot of hit and misses when it comes to data, but thats how one learns. The heads will be ported to the miniram, shouldn't be a problem getting them ported, but was curious how beneficial it would be to get the valves to 2.02/1.6 instead of the 1.94/1.5. Is there a large flow difference in the sizes or it is not enough to compensate spending the extra $$?

 

I guess it depends on how much $$ you are talking about. Yes, going bigger will help (as long as everything married to that valve is optimized). Grind a 5 angle and put a back angle grind on the intake valve itself (swirl will sky rocket)

Some minor stuff you do to the valve train...think about this...multiply that increase by 8 (you got a V8 right?).

 

I think I picked up on a v 5 + 3 so, if my basic beginners math is correct, and I use fingers to count, I have 2 left.. ....okay I give up.

Is there any flow charts out there between the stock 113s, ones that have the porting done with stock valves, and one that has been upgraded valve sizes with massive porting? What I am trying to get at is if it is worth the $$ putting into these heads is worth just sellin them back on ebay and getting some AFRs instead.

Hey at least I got my adcb's right.

 

bUmP

 

Well yea, but no problems there. That wouldn't affect your high RPM capability though, assuming you get the right valve springs. I think it was just inferred that faster ramp camps are not conducive to higher RPM usage, and i'm not sure why that is. I'm prodding for an explanation!


Depending on porting effort and ability, it's really hard to say how much flow you'll get, or how much power it'll make. 113's were supposed to be a low output SBC head, as far as flow (stock). If it's in the budget, AFR's would allow for room for growth in the future.

 

The super-aggressive ramps on some cams will beat the valve train to death and cause uncontrollable valve float from the valves bouncing off the seat. They're typically designed for various forms of RPM-limited usage; carb restricted classes, that sort of thing. For a good quick look at how aggressive some cam mfrs can get, look at the lobe spec pages at Bullet Cams. Compare the "low RPM" designs at a given .050" duration, to the "high RPM" ones.

 

ohhh, I get it, ok, thanks.