thx! Is this very similar for the 425 due to exact same heads? My 66 "feels" like it accelerates best from 3-4k RPM. A little tricky to specify a "stock" Buick NH cam due to the variability depending on year and engine. There was a document floating around here somewhere identifying the different cam options. If you flow the heads at 240-250 CFM, I've heard that the low end torque will suffer. Or another way to say it, torque curve peak gets pushed out to higher RPM. This is good for HP, but not great for low end torque required to move boats without the annoyance of 3k+ stall converters. GG did not recommend anything beyond Lvl3 for a street driveable boat. Does Dyno2000 see this in the analysis?
Yes, it's a little hard to determine the profile for a stock cam. I used the figures that Walt provided me for a stock '66 cam that he actually measured. Here is data comparing Gessler's level 3 heads to Mosler's (247cfm/188cfm); Gessler: Peak - 366hp @ 5000rpms, 435ft lbs tq @ 3500rpms. Average - 354hp from 4000-5500rpms, 423ft lbs tq from 2000-3500rpms. Mosler: Peak - 427hp @ 5500rpms, 449ft lbs tq @ 4000rpms. Average - 398.5hp from 4000-5500rpms, 417 ft lbs tq from 2000-3500rpms. I'll take the better flowing heads any day of the week. Here's dyno graphs for comparision. Also, the reason the numbers on the graph don't match exactly what I posted is due to a correction factor I use for the Nailhead.
lets see what the program says about one of the engines that was dynoed and the results posted. Do a compare, prgram to the dyno.:gp:
I did compare the program to Erik's build, and although it's hard to compare since I don't have actual flow numbers, the program was about 25-30hp short and about 20-25ft lbs tq short, although the peaks were at the correct RPM. I've always said that the program isn't always dead on number-wise, however it's fantastic to compare combo against each other. Does anybody have a link or info on Ted's 401? If I remember correctly, he dynoed his 401 at 377hp.
That thread is here. Have you compared any of these set-ups with headers vs. stock exhaust manifolds?
Great posting,thanks :TU: This will help me with portings. My coupe weight is only about 2400 pounds and there is 4.11 locker rear end plus 5-speed manual trans,so i dont think that low end torque is really important thing.Doesnt matter is it first,second or whatever gear on,when you release clutch pedal.Just only looking for power and raw sound :grin:
Here's what I get for the stock setup. -Head flow data is found on the TeamBuick page here: http://www.teambuick.com/reference/head_flow.php -Note the cam specs in the pic....those are actual measurements taken from a '66 401. -Headers are used as the exhaust parameter just to boost Hp/Tq levels up. The 'stock' exhaust' option kills the numbers.
Take that stock 401 and add a mild cam like a Poston NH400 (good) or the Comp cam (better) that Erik use, and you boost top end power, but lose a little low-end.
Now try a big cam like an Isky 310 and you boost power from 4500 to redline, but lose a ton of low end:
Can you identify NH400 and comp cam plots? One starts out lower with torque, but gets better at 4k RPM.
The Comp cam gives better HP and less Tq than the NH400 cam. You can download Dyno2000 or Dyno2003 yourself at the link I posted in post #37. I downloaded both, so it's a good link. The 2000 version is 1Mb, and the 2003 version is huge at 28Mb.
Actually , the best thing you could do to get power is to build a bigger engine.... because any mods you do is going to increase the power in small increments compared to the money cost... but say , you put a 364 or bigger engine in and in one swoop you gain big bunches of power.... that is why when Buick wanted the power increases, they went for ''bore and stroke'' rather than mods... yeah i know the super cats were available , but that was mods to engines that was already in production...and just building a bigger engine to start with will give you a reliable combo that will hold up under use....
I spent a little time with the Dyno2003 version. It is set up the same, but does have some added features that come in handy. For example, it has several variations of the 'dual plane intake' like a 'high flow' and 'high torque' version. Cam specifications include more options as well. Such as being able to vary the open/close ramps between oem 'slow rates to very fast ramp speeds. Best thing about the 2003 version is it comes with the manual!
Hey, take a look at the cams offered by Accelerated Motion. They have a few with the wide split duration! http://www.amotion.com/amcams.html#14841
I'm liking this cam; 223/234 .486/.490 274/290 110. Unfortunately, the company is closed until April 2010. Otherwise that's the cam I would be ordering. I might just have one custom ground to those specs.
The numbers for duration at .050" are pretty much spot on but you can get faster ramp lobes from Comp. 51* difference between the intake specs and Comp can get you the same duration or a degree more with 268* advertised, some difference, 6* less advertised for a degree more at .050", that's a lot for a hydraulic pushrod cam. Assuming that both companies use the common .006" lift for their advertised numbers. Same for the exhaust. 56* difference with that cam and comp would be about the same less as the intake, I'd have to check. That's why the dyno2003 program is more accurate. Duration doesn't mean that much unless the ramp of the lobe is taken into consideration. Comp cams are the number one manufacturer in camshafts these days. Best technology and equiptment. Stay with them. They will do that custom grind for you and you won't be dissapointed. Good Luck Andy, Tony
