|T O P I C R E V I E W
||Posted - 14 Nov 2017 : 10:44:00 AM
I'm building a .030 over 400
6x-4 (9.7:1) or 6x-8's (9.3:1) not sure which yet.
Currently have a 60918 cam on the shelf.
Running the Wallace racing DC calculator and it's giving me a DC of ~8.5:1 with the 60918.
Isn't this too high?
Secondly, I'm second guessing the 60918 and using the 60916.
I do have power brakes, and A/C. I also plan on a 200-4r this coming summer.
I do not expect much track time.
I'm having MadDog make me a set of headers this winter.
Stock Dual Plane
|9 L A T E S T R E P L I E S (Newest First)
||Posted - 19 Nov 2017 : 11:41:50 AM
You still run the 60243? I saw in a post you had mentioned it was a big soggy in a 455. What are the stats of your car? I'm not considering for this build but I have a 455 this may work for. Thank you sir.
||Posted - 16 Nov 2017 : 12:34:41 PM
With pistons in place, the top of the piston is .005" below the deck, correct?
Gasket thickness between manufacturers may vary, but a good rule of thumb is .039". Ideal quench, if there really is such a thing is about .045" or a little less. So, if the piston to head clearance is truly an accurate .005", your engine quench would be .044." That's darn good.
Either 6X head will give the same quench.
||Posted - 16 Nov 2017 : 11:11:44 AM
Last question in deciding on gasket and which heads. What quench distance do you recommend as a target. Deck is .005 but that is because the pistons require it.
||Posted - 16 Nov 2017 : 10:29:45 AM
The cam you already have, the 60918 with 112 LSA, 214/224 @.050", .444" intake lift, .467" exhaust lift using the 68404 springs set at 1.600 installed height.
||Posted - 16 Nov 2017 : 07:01:07 AM
Alright. So, in your opinion, will a street car, that will probably never see the track use a 60916?'I mean it's only a few hundred RPM.
||Posted - 15 Nov 2017 : 9:01:15 PM
Chris--the adjustable valve train Mark speaks of works with roller rockers or stamped OEM style rockers whether they are 1.5 or higher. The rollers are designed to be more accurate on the lift when one is trying to gain that extra few pounds of torque and hp. For a mild street engine, stamped steel works just fine. Stamped steel and poly lock nuts go together and there's really no reason to go overboard with large diameter ARP studs. If using the 60918 the lift isn't so great that it puts lots of stress on the studs. When lift is over .500" that's when larger diameter studs and increased valve pressure and installed height change the equation.
||Posted - 15 Nov 2017 : 12:20:49 PM
Thank you both for the response. MadDog is building me a set of headers next month, I guess they stopped making pontiac G body headers because they were too time consuming, when they could be making other headers. They agreed to take a few custom orders during the slower season, so those added with nice flowing pipes should work well. I just planned on static of 9.5, was gonna have 6x8's trimmed to 98,but then stumbled over a set of 4's. So its one or the other. I dont wanna use a cam as a crutch for too much compression, but I dont have 3o yrs of exp and I want a solid, usable motor with no regrets. I have the 918, but wanted input on other options as well. I understand Dynamic Compression a little more now, and realize thats what I should have been using to put this formula together. Do you guys have a "limit" to DC or Cranking compression that I could use (or you could recommend) as a target as I finish this build?
With the info you gave on an adjustable valvetrain actually answered alot of questions for me. Now I will ask, is it imperative I use roller rockers? or could I move forward with the stamped 1.5's? If I use the stock 1.5's do I still upgrade the studs due to lift? if so What Locks do I use at that point?
||Posted - 15 Nov 2017 : 09:48:13 AM
Chris--the Crower 60918, in a mild 400 build should easily run on 93 octane gasoline. It's built on a 112 LSA and will have plenty of vacuum for power brakes. I don't think you'll be disappointed with the performance on the street-highway with 6X-4 heads and tuned exhaust.
|Blued and Painted
||Posted - 14 Nov 2017 : 11:48:26 PM
The 918 looks like it a mild up grade over stock and could possibly use stock valve train components . The hi DCR number could make it fuel /spark knock sensitive. But should be fairly easy to tune for good drivability.
The 916 starts to enter the race category with its longer duration. Your rear gear and compression ratio would match up better with this cam. Some carberator mods may be needed for driveability. Hard to predict how the power brakes will react. It's not a huge cam so vacuum may be ok??
A fully adjustable valve train is advised. Aftermarket cams May use a different base circle diameter creating valve lash headaches.
6x heads usually have screw in rocker studs so an upgrade to the larger 7/16" stud is easy. But not cheep when talking new roller rockers and correct length push rods.