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Need recommendations for BBC 496 combo

4K views 18 replies 7 participants last post by  wildman926 
#1 ·
I am about to replace my 402 with a 496. The car will weigh in at about 3200lbs and I will be running a TKO600 tranny. Primarily street duty with occasional track runs. Would like peak HP to be in the 5800-6200 range. I would like to get as much HP/TQ in this rpm range, could go a little higher if necessary.
The heads will be #6272292 oval port open chamber iron heads. The heads have been deburred, bronze guides, larger 2.19/1.88 ferrea valves with hardened seats installed.
Any recommendations for:
Cam
intake
Carb
rocker arms
compression ratio

And finally any projected numbers for any suggested combos?

Thanks
 
#3 ·
Lots of guys running 496 here,do a search.Here is something for starters.
Edlebrock RPM
prosystems 950HP
comp gold rockers
low to mid 9 on compression
cam,hyd roller?Chris Straub,UDHarold,Mike Lewis
With the right cam around 550 HP at the crank
 
#5 ·
great spot for a roller cam. even a hydraulic roller with quality lifters at that RPM. 3200 and a stick opens up some options for you. RPM Air Gap, HP950 carb, keep the header tube size reasonable, no more than 2", maybe 1&7/8". Iron heads, don't go over 10:1 so you don't get trapped in some bad gas deal. Forged pistons for the NOS deal. Buy a cam from UD Harold here on this site. His phone # has been posted several times. something around 240@.050, 110 LSA. There'll be lots of options. Any quality roller rockers will work, I'm still partial to the Crane Golds, they're still out there. I'd avoid the various off brand/ ebay miracle deals there.

3200 and a stick, you're in a good spot to build a little more aggressive combo but I'd keep the CR lower to allow more aggressive tuning options and fudge against any further deterioration in the gas quality. You can get a little more power with higher CR, but if you have to back off the timing and fatten up the carb to keep the pinging under control that HP is gone and it costs you money and power every time you drive the car. IMHO, YMMV, others may differ, etc, etc.
 
#6 ·
You cant go wrong with the XR286 that I'm running - what a cam, idles pretty smooth at 1000, pulls up top as far as you dare. Should peak around 6100 for you. Carbs - cant go wrong with a 950HP or 1000HP, although they are a little to rich for alot of street time. Have prosystems build one for you.

496+XR286+1000HP carb+stick = a very, very, good time!

EDIT - and stout cam with have some difficulty driving at low rpms in OD...keep this in mind. My XR286 doesnt like being under 2000 in OD. Should have maybe gotten it on a 112 vs the 110.
 
#7 ·
Thanks for all the advice. Seems everyone agrees on the 950HP Carb. Tom thanks for the compression tips, will keep it under 10:1, more like 9.5:1. I will contact UD Harold for a hydralic roller that will meet my requirements. 69-CHVL great tip on the overdrive and cam combo I did not even think about that. I will have to take that into consideration when selecting my final overdrive ratio and when I talk to UD Harold, anyone got is contact info?
 
#8 ·
I have a 10.5 - 1 496 using the Voodoo 60234 (285/293, 255/263@.050, 685 lift), Victor Jr intake, Mighty Demon 850. Remember those cubes swallow up a cam, so what may be on the large side for a 454 will be on the small side for a 496. The longer stroke will dictate this. I am very happy with the setup, as they are all matched and have very good street manners.
 
#16 ·
Walter, how would your car do at 1600 RPM in high gear with converter locked? you think it would pull it with any issues? That's a lot of cam for an OD deal.
Walt, what gear and stall are you running?

I thought my 509 would swallow cam. I guess it probably does at higher speeds. But good thing I didnt go any larger, in fact, may be a touch to big for my driving style. The real issue is the fuel metering at very low rpms/high loads in OD, the carb just gets a little wacky.

As I stated earlier, the longer stroke will "see" the cam much smaller than a 3.76/4" stroke. My key words were "matched very well", with my 3400+ stall, 4.11 gears, and 29-30" tire. Now, if I were running a stick, it would be on a 112-114 LSA, just for the very reasons you guys that run a stick point out.

No, I don't think my cam is too large. If I were him, it would be on a 112. You have got to keep in mind, that the equivelant Hyd Roller to my cam is 277/286, 247/256 @.050 due to 8* being lost due to lash. That is NOT big for a 4.25 stroke motor. As I said before, and I will say it again, it is almost too docile for my liking. My SBC 355 was more of a handfull with it's 401A4 than this setup is.

If I ever change out the cam, I will go with the 502A7 on a 112 lsa. 292/300, 260/268@.050, 685 lift, or one like it on more lift.

To the OP, as Tom pointed out, you are a perfect candidate for a hyd roller, with your self imposed rpm limits.
 
#9 ·
Walter, how would your car do at 1600 RPM in high gear with converter locked? you think it would pull it with any issues? That's a lot of cam for an OD deal.

I guess Pat could just drop a gear if it started lugging/bucking/whatever. Sort of kills the whole OD concept though.

I tend to worry about detonation issues in the lugging condition. That's another reason I push lower CRs for these OD deals.
 
#10 ·
Walt, what gear and stall are you running?

I was actually thinking that my cam was gonna be a bit too small, and I was REAL tempted to go larger, cause I thought my 509 would swallow cam. I guess it probably does at higher speeds. But good thing I didnt go any larger, in fact, may be a touch to big for my driving style. The real issue is the fuel metering at very low rpms/high loads in OD, the carb just gets a little wacky. I bet fuel injection would help my situation out, but I just cant use OD till I'm really moving good, at least 1800 rpms in OD. That's why I'm looking to change my OD from .64 to .82.

Pat, what TKO - the .64 or .82, and what gear? I'll bet Harold will recommend the Voodoo 241/249 .625, but on a 112. There was a guy here who built a 496, but used the 231/239 .600 Voodoo, made like 575hp and close to 600ft lbs. His heads had some work I believe. I figure you will be at least right there.
 
#14 ·
3.55 rear, looking at the .64 OD. Dont think the .82 will give me the reduction I am looking for on the highway. Have also heard people complaining with jumping from 4th to 5th with the .64. Think I will have issues with the 3.55 rear?

Unless your truely going to be on the highway, I suggest the .82. The .64 will be useless unless your flying.

the 3.55 x .82 still gives you a 2.91 equiv rear gear....how much more OD do you need :D
 
#13 ·
with 3.55 and .64 your cruise RPM is going to be very low. I have 3.73 and .67 (200-4R) at 60 I'm at like 17-1800 with converter locked.

3.73 x .67 = 2.50 overall in OD

3.55 x .64 = 2.27

That's pretty stiff to be running any kind of cam at all. Maybe you can run 80 all the time? :)

the turbo Buicks and Monte SS had 3.42, overall 2.29.
 
#15 ·
If you are wanting a cam with peak horsepower around 6000 rpms, thats going to be a decent size cam, probably mid-240's or close to 250* @ .050". Not going to run good with the rpms at 1800-1900 on the interstate. With the 3.55's and a .64 OD, 70 mph will get you 1900 rpms. I don't think a cam that size will run properly down there. As Vince has stated in the past, it will make your OD unuseable for anything under 70 or 80 mph.

You are going to have to gear it up 4.10's +, get a .82 OD or drop the cam size (& peak HP rpms) way back.
 
#17 ·
I would use one of the Comp street solid rollers. XR286 works excellent. And use a set of Isky Red Zones or Crower HIPO lifters.
A Hydraulic roller will be less maintenance, but will float the valves when you over rev it because it's just feeling so good........
I have what would be a Comp XR304 if it were in the catalog, idles pretty mean, but even with a dominator is quite street friendly. It power peaked at 6250 in my 496 but will hustle to past 7000 in a heart beat. I would expect the smaller cam to power peak right near 6000.
Agree with the 950 - 1000 cfm 4150 carb. And I would go with a single plane manifold....one with long runner dividers. The world Products intakes are quite good.

BTW, my Comp cam is very similar to what Wildman would like to switch to:

"If I ever change out the cam, I will go with the 502A7 on a 112 lsa. 292/300, 260/268@.050, 685 lift, or one like it on more lift."

Mine is 260/266 .687 gross lift on a 110 LSA.

ron
 
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