Desktop Dyno 81 edelbrock heads and 268Cam

[Macgyver]

Hey where do you get that Dektop Dyno? Is it free? All softwares free now but was it meant to be? My next project is going to be a cam and head swap. I was wanting to either get the Dart Iron heads but Ii really dont want to increase the compression since Im using the OEM bottom half. So I was leaning more towards the Edelbrock Performer RPM heads. I wanted to dyno out the results of the 268 and 274 CompCams.

Im looking for 375HP/400TQ nothing too crazy. I just want to smoke this guy here w/ a Mach1. Seriously a $35K mustang! Its going to break down 5 times before you pay it off.

 

[drags1998]

It, at one time was a product of Mr. Gasket . Not FREE!!!! I have seen it work and its pretty cool!!! Im not sure how pricey the Edel. heads are, Take a look at Airflow Research Heads also, I had a set and they are AWSOME!!!!!!!

 

[Macgyver]

which ones did you use? On a C3 or C4?

I did look at the AFR's but they seem pretty pricey. If I was going to end up spending 1500 on heads plus cam and gasket. misc then it would probably be better to get an engine built for me by someone that will warranty it for a year or something for $2500. I was planning on keeping the budget at or below $1200. If I cant then I would jsut wait longer and spring for a new motor.

 

[Bob_K]

I've got desktop dyno. I think Jeg's still sells it. Anyhow, if you give me a little more info I can plug an engine in for you and tell you what it says. I need:
engine size (350 or 383)
heads (Think you said performer RPM's)
compression ratio
carb size (cfm)
single or dual plane intake
exhaust setup
and cam choices (you had mentioned Comp Cams 268 and 274)

You may also want to consider World Products SR Torquer heads if you're on a buget but want an improvement over stock.

 

[Macgyver]

Well its a 350. I think the stock compression is 8:4:1.
The heads are 170in/60ex with 70cc chambers
2.02/1.60 valve size. The rest of the specs are here I dont know what exactly you need.
Its an edlebrock 600cfm carb
Dual plane alum intake (edelbrock)
True duals 2.5 no cats and will have 1 5/8 headers w/ side pipes
and those are the cams that have been suggested but I would def want to look in to on eht atwould match w/ the heads perfectly. I would get the one in the Edlebrock perfromance package but that dyno'd a little too light for me.

Ill look into those heads right now, thanks Bob.

8:2:1 ratio actually. Im sure thats changed now overtime. If I get smaller chambered heads is that going to raise the compression ratio? Like 64cc.

 

[Bob_K]

Yes, going to a smaller combustion chamber will raise your compression ratio. I'm not sure what cc your stock heads are, so I just plugged in a compression ratio of 8.2 and came out with these numbers. Not sure how accurate they are, I've never had an opportunity to compare computer numbers to actual dyno figures, but here we go:

Performer RPM Heads SR Torquers
268H cam 323hp@5000 371ft-lbs@4000 232hp@5000 371ft-lbs@4000
XE268 cam 334hp@5000 371ft-lbs@4000 333hp@5000 370ft-lbs@4000
XE274 342hp@5500 366@4000 339@5500 363@4000

That's all assuming mufflers are attached as well, most crate engine dyno figures don't factor that in. The Performer RPM's didn't seem to do that much better than the SR Torquers, but since they're aluminum it should save you some weight. On the other hand, I've heard that iron heads make a hair more power because they hold their heat better. Either way they would probably be about even, and I think the SR Torquers are about $300-$400 less.
There are a lot of things that could be done to bump those numbers up too. A little higher compression, removing the mufflers would make it a more even comparison to crate engines (added about 20 hp and 20 ft lbs it looked like), and playing with the timing. I didn't do any timing adjustments at all (I always forget it's there).
I also checked, and Jeg's does still sell the Desktop Dyno 2000 software for about $40.

 

[Bob_K]

Sorry those numbers got run together. It was nice and spaced out when I typed it.

 

[goingballistic]

McGyver, take a look at the GM Fast burn Vortec heads, nice price. I wrestled between the AFR 195 and the GM Vortec, I opted for the AFR because I can afford them and am building a complete stroker from the ground up and what's a few hundred $$$ when you're building from the ground up :L and it's a nine month project anyway with my boys..........( at least that's what I told the wife ). Seriously, nice head though and around $600 a set. Good luck.


Paul.

 

[Macgyver]

Wow ok. But you put "Performer RPM Heads SR Torquers" does that mean that they mad about the same numbers? OH nevermind I figured you out now, left and right. Whats going to boost that though. Larger intake and exhaust ports?

Can you run these Dart heads for me please?

72cc combustion chambers, 180cc intake runners, 2.02/1.60 in. diameter intake/exhaust valves, 1.250 in. diameter single valve springs, straight spark plugs, assembled, Iron Eagle cylinder head
and
Chevrolet: 262-400, 64cc combustion chamber, 180cc intake runner, 2.02 in./1.60 in. diameter intake/exhaust valves, 1.250 in. diameter single valve springs, straight spark plugs, assembled, Iron Eagle heads

With both cams if its not too much trouble. My buddy put these Darts on his 67 Stang and said theyre pushing abotu 405-415 and hes the one thats going to help me do the swap. I think these might be the ones Im going to get.

Does it say though what these heads raise the compression ratio to?

Thanks Bob

 

[Bob_K]

I'll see if I can find the flow numbers for those heads when I get home from work tomorrow. If I can then I'll post as soon as I find them.

 

[Bob_K]

XE 268 341hp@5500 372ft-lbs@4000
CE 274 347hp@5500 367ft lbs @ 4000
I didn't find any difference in flow numbers between the different sized combustion chambers in the heads, but you would gain power by having a higher compression ratio. I and did the numbers above with the same 8.2 compression I did the other heads with, then changed to 9.0:1 compression and got these numbers:

XE 268 377 hp @ 5500 and 402 ft-lbs @ 4000
XE 274 384 hp @ 5500 and 397 ft-lbs @ 4000

As you can see the engine responded well to the higher compression. Another way to bump up power could be to use different rocker arms. You might want to consider using 1.6 ratio instead of the stock 1.5 It effectively makes the cam a little bigger.
I also found a ling to a website that has actual (not simulated) dyno results of 109 engine combos. Some of them are 350, some 383, but it gives a ton of options. Here's the link: http://ryanscarpage.50megs.com/combos1.html.

 

[Glensgages]

I ran .030"-over 350 with a 64cc DART iron head & flat-tops (10.3:1, I believe), with the 292H cam, Victor Jr intake, 750 dbl-pump Holley, etc.
In my '79 Z28, weighing 3800 pounds w/ driver, 8"/4500 converter, 4.10 gear & 28" slicks, I run 12-eighties @ 106+;
my g/f's nephew has a new super-charged Rustang (can't tell any of them apart...) that has run 12.88/111 with after-market pulleys, exhaust, NITTO's, etc.
Never had my Z28 on a dyno, but hope this helps...

 

[Macgyver]

Whoa wait you got the AFR195's for $600 for a set, two heads, complete and not bare? PLease show me the link. Yes, Ive been following your 383 build Paul and its what I wanted to really do but theres too much involved in building a motor. I figured a head and cam swap will be fun and put me where I want to be power wise. Ill save that dream 383 build for a later day. I looked into those Vortec heads and it would call for a new intake and I just put way too much into installing the new Performer w/ my minor mechanical expertise. But now Im a Master Mechanic.lol Im sure when i get the heads off Ill see the horrible truth that Im going to need an extra $2K for "misc" parts.

AFR adn Dart are supposed to be the best in heads right? Im an Edelbrock man now since theyve never done me wrong and worked great when others havent. THeir power package built w/ the Performer RPM heads and there 7102 cam made a 420 dyno run. I worried that that would be streetable and be too much power for my old bottom half.

Bob, thanks a lot thats perfect. I guess a good set of heads and a good midrange cam should get me a solid 340HP. I guess I should leave it at that ao that I dont blow the bottom out.

So those Darts never did you wrong Glen? Im really leaning towards those iron heads. But Im a capitalist and I want to support the people that have done me right and provided a good product thus far.

Good stuff, good stuff. Thanks guys for all the input. My question now is what the best way to match a cam w/ the heads. I dont want to build a dud if I dont go w/ the power package. I havent priced that sucker yet.

 

[Bob_K]

I think meant $600 for the Vortec heads. I saw a pair of AFR's for just under $600 on ebay once, but they were used in an engine that had "piston problems". I'm not sure what the guy did, but it looked like he loaded the pistons into a shotgun and shot the heads with them. New the AFR's are going for $1275 last I checked. Jegs has the Vortecs for $259 ea. Scoggin-Dickey offers (or at least used to offer, I think they still do) Vortec packages that include gaskets, intake, heads, and various spring upgrades to allow for more cam lift than the stock springs will allow.

 

[Glensgages]

So those Darts never did you wrong Glen?

We took the assembled heads outta the box, cleaned them off, and bolted them to the block in February '90;
they are still there, with the same gaskets between them...

 

[curtis]

I used the vortec package form Pace. For the money in my mind there is no better head. my motor is bore 30 over. comp cams extreme energy 262H hooker headers hooker 1 1/4 mandrel exhaust 600 cfm elelbrock. CHP built this engine and it made 430 ft lbs torque and 390 HP. Now Pace has the kit with heads modified to accomodate higher lift cams for about $800.includes intake gaskets bolts and all. super deal. My motor kicks butt with all that torque. I highly recommend the vortecs.

 

[goingballistic]

Macgyver, I was reffering to the Vortec heads sorry for the consusion, the AFR are $1300 a set NOT $600..............I wish. From what I can tell the AFR is about the best you can buy, hence the expense. Like I said $$ right now is not the major concern...........at least that's what I'm telling the wife :L

 

[Macgyver]

For the sake of your health I hope she doesnt see those receipts, because thats a stank load of cash, Paul.

Curtis thank you I just saw that pace package and it does seem do-able. Thats a good price for those heads and the intake. When you say CHP built that enginge are you referringt to the article that they wrote up on the 6part series of the GM block build up? Thats about the power range that I want to get to and I imagine w/o the boring that might get me to 365HP. I guess ill read that over again since that would save me some coin and they are some good heads.

How does the idle sound w/ the headers and all. i wan tsomething lumpy that just says get out of the way :cool maybe the next step of comp cams mi9ght get that better.

 

[curtis]

Super Chevy Dangermouse

OK. I messed up.....The engines I referred to are actually in "SuperChevy" magazine. The tests with the vortec heads ran in January and February of 2003. If you can't get these results from the web site , email me and I will scan the pages and email themto you. My exhaust is probably a little on the loud side. No real mufflers, just the Monza twin tips that you can look thru. The Extreme Energy 262 hydraulic flat tappet cam in my motor have very little porrump. Not lumpy. Runs 20" vacuum at 800rpm. It is kind of stealthy till you tromp onit and then it roars. Fun watching in the rear view mirror at the black marks and the competition. For lumpy idle you'll need more duration inthe cam. The XE278H will give you that, but you sacrifice idle vacuum badly, as well a low end and peak torque, but you gain 20 hp on the top. For the street I like my 430 lbs of torque. IF i ever figure out how to put pictures on this site I'll put up a few. I've done all the work myself in my tiny garage.I've got about $18000 total in the car and hundreds hours work. I think they will probably bury me in the thing.