63mako

The piston volume is definitely not 14.5 CC. It is 5 or 7 CC. Figure 5 to be safe. As I said, take the DCR calc with a grain of salt because AFR heads will fill the cylinders and that increases cylinder pressure. I would not use a cam smaller than that 290 with 112 LSA especially if you can't always get 93 octane.

76strokervette

Bailey engines on ebay has pro-filer heads listed for delivery within a few days.Chad Speier is another great source.Do you plan on running
side pipes?If you do you'll probably need straight plug heads.I 'll be posting more pictures soon, providing the weather behaves.The price will be as you stated but I believe it will be worth it to make everything match.Afr heads are an excellent choice but they only offer a straight plug head up to 195cc.I actually took my ss side pipe header to summit
and checked the fit to an afr 210 head.That's when I realized that side pipes will need straight plug heads.Hope this helps.

vettezobsezzed

vettezobsezzed

The ones I had a lead on we're straight plug, from what I gathered would be good to run with headers. I'd love to run side pipes, end goal for sure, I just lve the look, and I'm near deaf anyways so the noise shouldn't be an issue. Haha.
Defiantly don't have the option of going to a "summit" in person, if I did I'd probably never get out of there. I can lose an hour in a hardware store... Looking at nothing, take all day in a place like that!

REELAV8R

Looking at those pistons, I would agree with Mako. They are flat tops with two valve cut outs, max of 7cc's.
If you want to re cc the pistons to double check, look here at post # 30 to see how I did it.
http://forums.corvetteforum.com/c3-t...er-size-2.html

vettezobsezzed

Ya, no I didn't do that. I actually picked up a piece of plexi glass for this task, then didn't bother with it. Firstly I filled the valve reliefs until it spilled out (5cc) then cont to fill cyl until it spilled over at aprx 19cc. I realized this was going to be inaccurate, but Thot I'd enter it here fwiw. I am confident in the 5cc measurement of the valve relief, as the result echoed the result I expected to find.

So throwing out the piston top measurement and going with math, 0.020 in hole, 4.185 bore, being 4.5cc and valve relief of 5cc, 9.5 cc total volume. Now, the question I have is where do I go with this number, and is it in my favour with these heads or no?

REELAV8R

No improvement with this knowledge. The DCR calculator accounts for the volume of the cylinder when you put in the distance down the bore.
Would work to the heads be in your budget?
what I'm thinking is talking to someone who ports and see if the head volume could be opened up to bring the CR down without changing the shape or burn characteristics of the combustion chamber. If you can get it up to 72 cc's then it would be doable at your altitude and your original cam specs. Maybe de shrouding plus a little more?
It's a stretch since the cost of this may completely defeat the purpose of a good price on the heads to start with.
Is the deal good enough to buy the heads and trade them for something that will work with your pistons? Maybe a performance shop around there has some heads they'd be willing to trade for some 65cc AFR's? Or Craig's list trade?

I'm just not a fan of big squish dimensions and high CR's with pump fuel, so trying to come up with other alternatives.

bluedawg

I thought the same thing, went to the one in sparks Nevada, not as impressive as i thought it would.

vettezobsezzed

I don't think I'd be interested in having the heads ported, the wouldn't be that cheap, so no value gained there, I dunno. Maybe I'm back to the drawing board. I started re checking the profilers on eBay, then the total cost is a wash over the ones that are local to me. I did find a guy local that can get the profikers bare for $900 a pair, but I wasn't sure if the value was there either, I kinda like plug and play. And I'm not sure if that offer is still available.
Had I pulled the trigger at Xmas time, like I was gonna, at least the exchange would have helped a bit.

vettezobsezzed

Bluedawg, your runnin a 400 with AFR, how does yours spec out compared to this racket I'm getting into?
Snow melting there yet?

bluedawg

Due to an internet order mistake i ended up with a 9.2 to 1 compression and am running the xe288hr on paper makes the dcr on the low side. When i had the 700 r4 built the first time the 2400 rpm stall mysteriously was replaced with a stock stall, it would still burn the tires, but seemed to come alive at 3000 rpm. When i broke that tranny due to hansens transmission not having a clue how to build a 700, i had affordable build the next one and put a 2400 rpm stall back in. I have traction issues with 3.08 gear, now its super fun to drive, for your compression ratio and the camshaft that mako specked out looks good, like mako said with the afr heads and a roller cam, you'll love it, in comparison to mine yours should be even funer a little higher compression. You've stated that you wont see the top end that much, but its so hard to keep you're foot out of it you'll see it more than you think, with the appropriate size stall you wont notice the larger camshaft on the bottom end. If i were going to do it over id probably go with the 210's higher compression and a bigger camshaft. Dont buy a chep converter, money is spent well here to have normal driving and the performance with out comprimise. I say build it, i havent figured dcr on your plan, but like i said mine is like 7.35 or so which is low, but my vette eats my daughters 2011 gt 5.0 with out issue. If you could go with the afr 75cc chambers you could use a different cam shaft. On youtube look up 77 corvette burn out, several will come up, look for the black corvette with the alaskan lisence plate that say diggler. Thats Bryan, hes at 11.2 to 1 static on his 406" and up here all we get is pump gas of a 90 octane, it runs on pump gas, but it took extra attention to valve timing events.

vettezobsezzed

Fooling with valve timing is something I've never experimented with, only ever lined up dots and called it good. Giving how close to is to the edge, I'm not sure I have enough margin of error to dump this cash.

bluedawg

mako seems to have mastered valve timing events well, if i recall correctly, his 383'' has 10.8 to 1 and I believe he runs on pump gas. As for the margin of error, buy the 75cc heads, straub technologies has afrs for $1600 delievered last time I checked. if you buy good parts now, they can be reused later as well, with your 509 block being .060'' over, if it breaks you'll need to rebuild then with a different block and such, you'll have good parts to use. you could probably do the top end with afrs and a roller cam for around 3500.00, the torque on the 400'' pins me to the seat at half throttle and if you build a 400'' now even if its on the mild side, you wont want to go back to a 350''. The snow is melting here and the roads almost dry enough to get the vette out of the garage(yeah!). Had her out last month for 5 days. If you were honnest about parts being used for the next build as well, do your self a favor and don't skimp on the heads.

Here is the video of Brians vette. Like I said its 11.2 to 1 and were at see level. He runs afr 210'a, 75cc chambers, flat top pistons and a solid roller cam, 3500 rpm stall and 3.7 to 1 rear gears through a turbo 400.

REELAV8R

Ran some numbers through the DCR calculator. At 2200 ft it looks like you need a intake valve closing point of 74* or later to get the DCR to 8.2 or lower. This is assuming 5 cc pistons and all other parameters as originally posted.
This cam can do that.
http://www.summitracing.com/parts/cr...make/chevrolet
It says 3000 to 6000 rpm. For a 412 that may be more like 2500 to 5500?
Putting it into the calc it comes up 8.19 DCR.

If Mako63 would chime in, he would have a better idea about this.

I'm not an engine builder by profession or anything like some other people here are.

vettezobsezzed

For sure there's no more go's left in the block, that's why I figured I stay with heads with the smaller chamber. For the next build I don't have any fantasy about getting 50k miles out of this, just one kickin summer out of it, so I can start my next project. It's just sitting on the stand dying to be used up and thrown away. The heads are the key piece I want for down the road, but I'd like to slap them on the 400 and go for it.

Flat tappet idea tickles my wallet for sure, because the earlier cams would really only suit this app. For roller money, I'd like to recycle, flat tappet. Could go to scrap with the block if It didn't work out. I guess really I'm only scrambling a plan, this deal I got my eye on wont last, so I gotta act now or continue shopping.

vettezobsezzed

That's like ****! I can see my self doing that, but pulling it off is another story all together!

v2racing

I hate to be a Debbie Downer, but a 400 block bored .060" over with stock rods may not hold up to the power you can make with good heads very long. The rods are weak and the rod angle is terrible. This puts a lot of side thrust into those very thin cylinder walls. The more power you make, the higher the thrust pressure and cylinder pressure. You might get away with it. I've seen things that shouldn't have lived at all go for quite a while, but then I've seen engines blow the first time they were throttled up too. I wouldn't put a lot of money in this if I was you. Put the old iron heads back on and use it like it is while you collect parts for something that will give you what you want and live for a good while.

As far as DCR goes, nothing is written in stone. Look at my engine specs in the screen shots of this DCR calculator. First shot is compression, the second is DCR. This engine runs on good 93 pump gas without issue. It is the engine in my signature and was in my 80 Vette for 4000 miles. I carefully tuned it with a digital wide band sensor and a vacuum gauge. I carefully worked on my timing curve and used an adjustable vacuum advance that I built a limiter for it so I could limit it to 6 degrees total vacuum advance at cruise. As you can see in the DCR calculator my quench is very tight. This helps eliminate detonation. My cooling system was very good and I ran a 160 thermostat. That also helped. According to most people and articles, my engine shouldn't work on pump gas, but it did flawlessly.

93 octane has all but disappeared around here the last couple of years. I know of one BP with a dedicated 93 hose. There are a few more with shared hoses, but you can get up to 1 1/2 gallons of 87 before you get your 93 out of them. I may have to go to E85, which is everywhere around here. I already have most of what I need to do that.

bluedawg

I wish we had e85 up here. Health and welfare of the block is why I asked about .060'' over. With flat top pistons it may not have stock rods though.

hugie82

That's a badass little mouse. I thought he was parking in the woods there for a second but he pulled it out! to everyone that drives their vette like they stole it!!!!

vettezobsezzed

Well It's my understanding your numbers are tighter then mine, you got quench goin for ya tho, so this isn't wacky idea I got, just a litte eccentric we'll say.

I know the ole girl might not take it, but it's a risk reward thing, if it blows up and it was fun, I can live with it, if it sux ****, and doesn't blow... That's my biggest fear.