|06-12-2010 10:22 PM|
those are respectable numbers. i was reading your earlier post about the comp cams dyno sim and the 500+ numbers it gave you too and i too thought it was a good bit inflated. with everyone i have talked to the edelbrock heads are really not that impressive, the victor heads i have been told aren't too bad though. if you ever feel the need to up the power in the motor i would suggest taking the heads to your closed performance shop, and get them unshrouded, valves back-cut, and some minor port work. this will probably run you about 400.00-600.00 depending on how much time they spend on the heads, and make sure that what ever shop you have them done at has a flow bench this way you will acutally be able to see the improvments. but i think just his could be an increase in 25-30hp
|06-12-2010 06:25 PM|
Just figured I'd update this thread with what the engine actually made on the dyno. I ended up using the edelbrock rpm heads with mild port work and a 750 ultra double pumper carb, and a timing chain instead of the gear drive. The rest of the parts are the same as the the original post.
|08-29-2009 01:12 PM|
|my87Z||since im back on here again, its been a while, i will rep the dart iron eagle platinums or the RHS pro action heads, at about 200cc, they flow consideriably close to the AFR-195's for $500 less, nothing aganst AFR they are great alm heads|
|08-29-2009 02:56 AM|
Once again thank you for the info. I plan on taking my heads in and getting them ported. I have talked with a couple local machine shops and with people that have dealt with them. I found a good place to deal with so I will take them in and see what they can do with them. I would really like to see those 500's
|08-25-2009 08:02 AM|
|ap72||While you're at it get timing and fuel tuning for taht engine, the headers used, what kind of water pump etc. In those "little things" alone you can make up close to 100hp on a dyno... and then you put it in yoru car, tune it down just a hari in case of a tank of bad gas, use headers that fit your chasis and your "500hp" engine only has 300 at the wheels...|
|08-25-2009 02:45 AM|
Tell you what, I'll just post the flow figures I used in that second pull and you make up your own mind what you want to do. I would never suggest that you spend another nickel if you don't have to. It's just too shaky taking the word of a software program when $1500 is at stake.
.100 70 57
.200 131 107
.300 192 156
.400 231 177
.500 253 184
.600 263 188
.700 256 189
If you go to AFR's site and look at the dyno results they have posted, you'll see 500/500 from their 195 Street heads in a 9.5:1 383. Call them up and talk to them. Ask them under what conditions the dyno pulls were made and if you could expect to duplicate the numbers. Maybe they'll tell you the truth, maybe not.
|08-25-2009 01:55 AM|
Thank you for taking the time to run my set up on your DynoSim. I did pick all the parts for this build, I by no means claim to be an engine guru, but I have built several 355 for my stock car. So more head you say. Is it worth while getting these heads ported or is it better to go Worth a different set of heads? possibly a set of AFR 195cc Eliminator Street Cylinder Head? or?
|08-24-2009 08:37 AM|
Another option would be sending them out to be ported and finished, that (depending on the guy that does it) can get you to your 500/500 goal. Or selling them and using the money to buy a 210cc-ish iron head for about the same money.
When it comes to power I have yet to see any advantage in aluminum heads- however they do machine easier and repair easier and there is a lot to be said for that.
|08-24-2009 04:37 AM|
|08-24-2009 04:34 AM|
|TorkMonster400||Don't we all|
|08-24-2009 04:13 AM|
First, let me say that I've had enough feedback from several different sources including professional engine builders who flow these heads in the real world to convince me that flow figures published by head manufacturers are pretty much bogus and are inflated in order to sell heads. Since I don't have the facilities to flow each head before I enter it into the DynoSim software, I've decided to factor published head flow by .90 in an attempt to approach reality. I'll post that caveat on each DynoSim pull that I do from now on, including this one for you.
Now, with that said, it looks like you'll need more head to reach 500/500. On a brighter note, I don't know if you chose the cam for this combo, but if you did, kudos to you. You nailed it. I couldn't find any more power with less or more cam on this DynoSim pull.
It's a shame that Edelbrock hasn't stepped up to the plate with the RPM-XT head for the small Chevy. They have it available for the 351 Ford, but not for the SBC yet. That's the head that a 383 needs.
Using 64cc heads, 6cc's in the piston crown, an 8cc gasket and zero deck, I calculated a 11.05:1 static compression ratio for your build.
THE PUBLISHED FLOW FOR THESE 60899 EDELBROCK RPM HEADS HAS BEEN FACTORED BY .90 FOR THIS DYNOSIM PULL.
RPM HP TQ
2000 145 380
2500 184 386
3000 235 411
3500 296 445
4000 355 466
4500 404 471
5000 442 464
5500 460 438
6000 448 392
Peak volumetric efficiency 99.5% @5000
Peak BMEP 185.7 @4500
1.6 rockers on both valves will only add 6 hp, so I wouldn't think it would be worth the extra stress on the valvetrain.
Just because I like doing this, I ran the numbers on the RPM-XT Ford heads and factored them by .90 as well, figuring that when Edelbrock releases the Chevy head, it will be close to the same flow as the Ford...I used the same cam as above...
RPM HP TQ
2000 144 381
2500 183 384
3000 236 414
3500 303 454
4000 369 484
4500 427 499
5000 473 497
5500 499 476
6000 506 443
6500 477 385
Peak volumetric efficiency 104.7% @5000
Peak BMEP 196.5 @4500
It's clear that your combo needs more head.
|08-24-2009 01:13 AM|
|08-23-2009 03:15 PM|
I might use this set if I were building a more performance-oriented motor. Both sprockets are hardened and the set is hand-matched at the factory....
If I were interested in changing the cam phasing to find the sweet spot cam-crank I might use a Hex-A-Just set like this...
and a timing cover like this to allow easy access to the adjustment....
|08-23-2009 02:42 PM|
|Steel||I will say this on the gear drives. I "thought" I would like the gear drive whine in an engine I built a couple of years ago. Well I thought wrong, I hated it so much that a month after I rebuilt the engine I pulled that POS out and put in a good chain set-up. I ended up going with a Cloyles Double roller set up......|
|08-23-2009 02:13 PM|
|MUD CHILD||Thanks for the input, I will ditch the gear drive in favor of a good timing chain. Any suggestions as to which one to use?|
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