496 engine combo???

[tubbed55]

I am just now starting my project again after recovering from being hurt at work... I am starting to buy everything I will need to start my engine build. I was going with a 496 scat crank, H-beam rods, and dome forged pistons. I have Merlin World Grumpy Jenkins 119CC iron 320 runner rec port heads with 2.30-1.88 valves. The piston catalog states I should have 10.2 CR. I have an Weiand Team G dual plane rec port intake. This motor will only be for street.. Want good power and lots of thump...I am looking at the Lunati Voodoo #60213 Hyd roller. 241/249 625lift on 110. I am also trying to research which carb would be best...I was looking at the 850 Mighty demon Annular Mechanical Secondaries. Does this combo seem like it will work good? Anyone have anything to add or take away? Can anybody take a stab at HP and Torque numbers? Thanks, Ronnie

[18436572]

Desktop simulator says 650 hp and 615 tq with 850 cfm card
with 1100 cfm says 671 hp and 650 tq

[tubbed55]

Wow, that are better number then I was imagining.. I was afraid of the dreaded "over carbing"...

[18436572]

Your heads and pistons and cam should be an excellent combination.
Hope you have the correct transmission/torque converter and rear end gears for this engine combo

[tubbed55]

I am using a Turbo 400. Have not settled on a torque converter yet. I was looking at a 2800 stall.. From what I hear is that with my power combo the real stall should be around 3000 with this converter. Any recommendations?? My truck has a 9" with 4.11 gears. The rear tires are 31X18.5X15.. I need to get a new photo.. I have since put a Mustang II under the front, hung the doors, and cab is ready for paint...

[tubbed55]

Someone else suggested a 750 CFM vacuum secondaries carb is a all I would need. What would be the pros and cons of using either vac vs. Mechanical secondaries? Would a 750 be enough for my motor on the street? Seems a little small for my runner size?

[mrbigg]

Someone else suggested a 750 CFM vacuum secondaries carb is a all I would need. What would be the pros and cons of using either vac vs. Mechanical secondaries? Would a 750 be enough for my motor on the street? Seems a little small for my runner size?

You could use that carb on the street but you'll be giving up horsepower. I'd make sure to jet it correctly. I had to use a 600 on my 454 while I'll was waiting for the parts to rebuild my 850. The throttle response was excellent. I rapped it out a couple of times and checked the plugs. They were lean on the top end.

[18436572]

The stall should be 3000 +
With an automatic tranny I would go with vac secondaries
I would run the 850 + otherwise you are leaving a lot on the table

[tubbed55]

What does anyone have to say anbout the Edelbrock thunder series 800 CFM. Being a street only truck would this even be a choice for my setup? Thanks to everyone for their help. Just trying to make sure I get a good powered reliable motor the first time out.

[jerry clayton]

Go with the biggest mech sec Holley type(Demon) carb you can get---remember that just driving around you are on just the primaries and the seconaries only come into play when you get on it---

I find it very interesting that everybody does all this number crunching desk work and determines that an engine only needs this or that number of cfm, and use that as referance for total flow---however if you said that you were going to run a 2v they would be all over the 500cfm one, but would only want you to run a 600 4v----

Carb tuning of high output engines for the street evolves around BIG, and drivability is centered on PVs, Accerator pumps/nozzles, and transfer slots/proper relation with throttle blades

And of course an reasonable idle speed with decent advance curve in the ignition

[tubbed55]

Really appreciate all the help. Guess I will stick to the original plan and stay with an 850 mech secondary. I guess the great debate between Demon and Holley is like Ford and Chevy. Pat glad to see you back posting. Hope you get a speedy recovery. Have any options about my engine combo and what carb you would use. Thanks, Ronnie

[pat mccarthy]

thanks most all the 496 street builds i use the smaller runners and O ports heads the 800 edy works but most builds are street strip so they may not play with them as much as you can with the 850 dp holley is fine as with your build. you have a bit more cam then i use in most of the street /strip builds but more stall helps this all work . i do have a new hyd roller erson cam 585/585 242/250 on 108 that would work nice in your build . i would try to bump up your CR or move down on the cam like the 627/627 238/246 on a 112 and less stall and i have one of them new in a 7/4 swap as well

[tubbed55]

I know someone who has a retro Howard Cam and lifters for sale for cheap... 236/242 @50 degrees, 620 lift, on 112 center. Didn’t look too much different then my Lunati I was looking at. Are Howards cams any good? Will it be much different in power and sound....I have heard the Lunati and want to keep the same type idle.... I had someone tell me I would not be able to tell the difference in those two cams by the sound. He sadi they would sound the same... True????

[tubbed55]

may have a chance of getting a Holley 870 street avenger...Good for my combo or no?

[pat mccarthy]

I know someone who has a retro Howard Cam and lifters for sale for cheap... 236/242 @50 degrees, 620 lift, on 112 center. Didn’t look too much different then my Lunati I was looking at. Are Howards cams any good? Will it be much different in power and sound....I have heard the Lunati and want to keep the same type idle.... I had someone tell me I would not be able to tell the difference in those two cams by the sound. He sadi they would sound the same... True????

well i know 3 companys that grind the same cam spec s and could be ground by one of the bigger cam grinders just in another box with stickers . less you have your engine running with your cam then swap it to lets say a howards with the same specs should be some what the same sound if every thing is the same howard cams are good , it the quailty of the cam and cam numbers as they apply to your engine . your numbers are what i used i 496s i will add that the roller lifters on your howards kit could be better as your heads will make power past 6000+ and the lifters may not and should check with howards for max rpm of them is under 6500 i was just looking at your luati no there not the same or close as i see it your 5 more on intake side and 7 on ex and ones on 110 and other is on 112 there miles off the way i see it but like i told you less your moving up on CR i would use the 238/242 on 112