BBC 496 cam selection.

Rannos · Post by **Rannos** » Sat Apr 04, 2015 8:42 pm

I am starting a 496 BBC build and would like some idea on cam selection. The build will go in a 3600ish lbs (with driver) street car and see both street and strip use. As of now it will be 10.4 to compression with fully forged internals. I will be using a set of 188 casting rect. Port GM castings that have a good valve job and that's about it. Intake will be a Victor or Strip Dominator with a 950hp carb. I am looking for a solid roller camshaft that's doesn't require crazy springs pressures as it will be driven almost every weekend on the street. It will also see 150-200 hp nitrous at the track. The rest of the drive train is a Trans king turbo 400 w/a probrake, 4500 stall and 12 bolt rear with 4:10's. Sitting on 30x14.5's Hoosiers out back. My goal is mid to high 10's on motor and maybe a 10.0 or 9.90 on nitrous while keeping rpm 7000 or below. Any suggestions would be appreciated.

bigjoe1 · Post by **bigjoe1** » Sat Apr 04, 2015 10:15 pm

I know this will not help you, but you are expecting WAY TOO MUCH

JOE SHERMAN RACING

user-612937456 · Post by **user-612937456** » Sat Apr 04, 2015 10:35 pm

As you are building you will need forced induction to break into the sub 10 second range at 850 Hp +. It will have to be an extremely radical build to achieve this level in NA only form.

vortecpro · Post by **vortecpro** » Sat Apr 04, 2015 11:45 pm

I don't see the NA goals as unrealistic, I would forget about the nitrous.

rocketracer380 · Post by **rocketracer380** » Sun Apr 05, 2015 12:08 am

I went 10.16 at 132 in a 3300lb nova with a pump gas 434 sbc at 10:9 to 1 comp with afr 135 eliminators and spring friendly .649" roller I think his goals are attainable ive gone similar times with factory square ports at 468 " twenty years ago !

rocketracer380 · Post by **rocketracer380** » Sun Apr 05, 2015 12:14 am

I ran a lunati .725" .725" solid roller in my 468 more than adequate to achieve those goals ran a comp .714" .680" roller also both in hi comp 468s 5000 + stall 4.88 30:10/5 tires

stokerboats · Post by **stokerboats** » Sun Apr 05, 2015 12:53 am

Shoot for the Moon! Determination will get you where you want to be. Nitrous makes power but it can be a PITA in hot weather.

BlackoutSteve · Post by **BlackoutSteve** » Sun Apr 05, 2015 2:02 am

If you are starting a 496 build with intent of using a solid roller that I reckon will most likely need moderately high or "crazy spring pressures", get yourself a Gen V/VI or a Dart block.
You'll have another ~45 cubes straight off the bat with the same 4.25" crank, better breathing with a 4.5" bore, and most importantly, longer lifter bores that are designed for rollers..
Forget Mark4s and rollers.

If you insist on a Mark4, welcome to the club and get your wallet out.

vortecpro · Post by **vortecpro** » Sun Apr 05, 2015 8:36 am

560 HP will get that car well into the 10s easily, high 10s if you have no idea how to run a car. Any self respecting 467 can do that easily with a very mild street roller. If you use the right solid roller lifter with the right clearances you will not have any problem with a production block, infact we just tore apart one we ran 7 years with a solid roller that was raced in a street car class you drove 120 street miles then pulled into the track and raced heads up, looked very good after the teardown, and I might add it was very cost effective. I will post a picture of the 7 year old lifters run in the production 289 block, and actually I can post picture of the pristine lifter bores as well. Personally I'd be looking for 9s NA OP.

monte442 · Post by **monte442** » Sun Apr 05, 2015 9:57 am

vortecpro wrote:I don't see the NA goals as unrealistic, I would forget about the nitrous.

I completely agree with Mark,he knows these combos very well. That combo is more than capable of 600+ with a hydraulic roller ,which should put you deep into the 10's,even faster if the chassis and drivetrain are optimized.

Post by **CamKing** » Sun Apr 05, 2015 11:43 am

Using the flow numbers from Stan's database, this is what I recommend
Cam# BBCR, R79421A-80424-110
263/274 @ .050"
.421"/.424" Lobe Lift
.715"/.720" Gross Valve Lift
.699"/.700" Net Valve lift(after Lash)
110 LSA

F-BIRD'88 · Post by **F-BIRD'88** » Sun Apr 05, 2015 5:47 pm

If the car really is 3600 lbs w driver you will need a 625HP street motor to run a 10.90 et in a street car.
And need 825 HP (or more) to get to a 9.90 ET. (I assume this is a typical "street car" not a dedicated drag car.
If the car w driver is heavier you will need MORE POWER.

What ET MPH does the car run now? What does it really way? 3600# is not 3800#.

The "street" solid roller cams that are the mildest and run with the mildest spring pressures , that I know of are the COMP extreme energy roller cams. ( wether you can get in excess of 600HP with one is another story.)

They are not bad for street durability if you keep the lash set tight.

But you want to run at LEAST the minimum recomended springs and pressures and very well may need MORE spring pressure than this.

1. Your heads will need a LOT MORE work. Easier to start with a MUCH BETTER head.
Easier to just build a (low low cr) pump gas supercharged 496 street motor.
Easier to lighten the car.
This is why they have 620 HP 572 cid pump gas BBC's.

The easy path is adding a 8-71 roots blower. The place to start is to get the true all inc weight of the car.

BlackoutSteve · Post by **BlackoutSteve** » Sun Apr 05, 2015 6:56 pm

vortecpro wrote: If you use the right solid roller lifter with the right clearances you will not have any problem with a production block.

The correct clearances and lifters are?

vortecpro · Post by **vortecpro** » Sun Apr 05, 2015 7:05 pm

"If the car really is 3600 lbs w driver you will need a 625HP street motor to run a 10.90 et in a street car.
And need 825 HP (or more) to get to a 9.90 ET. (I assume this is a typical "street car" not a dedicated drag car."

Its hard for me to agree with this post because in my experiance I have several examples to the contrary. Heres one:

Victors .030 oval port flattappet 454
4200 pounds
3.55 gear
Turbo 400
Fully loaded
626 HP dyno HP
Pump gas
Always driven to the track
11.0 @ 122 MPH

I really believe a 10.4 compression 496 with a solid roller and rectangle port heads can easily run faster than the OP expectations.

F-BIRD'88 · Post by **F-BIRD'88** » Sun Apr 05, 2015 8:37 pm

vortecpro wrote:"If the car really is 3600 lbs w driver you will need a 625HP street motor to run a 10.90 et in a street car.
And need 825 HP (or more) to get to a 9.90 ET. (I assume this is a typical "street car" not a dedicated drag car."

Its hard for me to agree with this post because in my experiance I have several examples to the contrary. Heres one:

Victors .030 oval port flattappet 454
4200 pounds
3.55 gear
Turbo 400
Fully loaded
626 HP dyno HP
Pump gas
Always driven to the track
11.0 @ 122 MPH

I really believe a 10.4 compression 496 with a solid roller and rectangle port heads can easily run faster than the OP expectations.

Your post example does more to support what I am saying, than otherwise.

Don Terrill’s Speed-Talk

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