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Discussion Starter #1
Hi Harold,

Need a solid flat tappet cam recommendation for a nostalgia hot rod I'm building. I'll be a weekend toy with 80% street & 20% strip use. I'm stuck with GM alum heads cause it's an old school build.

496 with 10.2 CR
GM alum C port heads 077 castings 2.25/1.88 gasket matched intakes

Going in a: Straight axled ’51 Chevy Bel Air, 3.73 rear, TKO 600 (2.87 first/0.64 fifth), fenderwell headers and cheater slicks.

I have a GM high rise alum intake I may run unless I find something better that fits the era I'm going for and will probably buy a Holley 850 DP to put on it.

I want to pull as much power out of it as possible and still be able to turn a low mount AC compressor (can use a fast idle solenoid if needed - think Texas heat:pout:).

Thanks for your help,
Dan
 

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Looks like Harold is busy. Anyone else have a recommendation?

I'm thinking about using either a Comp Cams 280S or XS282S.

Anyone have good or bad things to say about these?

Thanks, Dan
 

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Ran the xs282s in an 11:1 street 396 with factory oval ports- loved it.
not sure if thats enough cam for a 496...sure someone will chime in.
 

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Lunati 402A7 -

Solid, rough idle. Good cam for bracket racing in 396-454 cubic inch motors. Needs 3500 RPM stall converter, headers, 10.5:1 compression ratio and 4.10 gearing.
Advertised Duration (Int/Exh): 288/296
Duration @ .050 (Int/Exh): 255/263
Gross Valve Lift (Int/Exh): .612/.630
LSA/ICL: 110/104
Valve Lash (Int/Exh): .024/.026
RPM Range: 3000-7000

HERE is a video of it running in a 496. Sounds incredible, with that distinctive Harold cackle.

I run the roller version of it, Lunati 60234. It has a tad less seat timing, and is somewhat tamer sounding because of it.
 

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I have a Lunati 402A8 cam and lifters new still in the box. Never opened. I ended up going with a solid roller. I will let it go pretty cheap if you want it.
 

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I run a comp XS290S/11-679-5 (solid ft) in my 496 (10.7:1) edel oval ports and it works very well. run a vaccum reservior for the power brakes but the very sassy idle makes it worth it. the brakes work great too....
 

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I have a Lunati 402A8 cam and lifters new still in the box. Never opened. I ended up going with a solid roller. I will let it go pretty cheap if you want it.
I would highly suggest the 402A8. I ran a best of 10.49 @ 128 with this cam in my malibu at 3034# (w/out driver), in a little 454. This cam has great idle characteristics and vacuum, and was streetable. Obviously it will be a pinch more tame in a 496, which will be even better for you in a street/strip application. This was using an off the shelf Hughes GM40 4000 stall converter...
 

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Walter..that elky sounds GREAT! slobbering all over itself, yet butter smoothe at the same time!:thumbsup:

what exhaust/mufflers are you running?
 

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Discussion Starter #10
Thanks all for the replys.

Sinister - I think the powerband on your cam is a littler higher than I was looking for, but thanks for the offer.
 

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Walter..that elky sounds GREAT! slobbering all over itself, yet butter smoothe at the same time!:thumbsup:

what exhaust/mufflers are you running?
Sorry, just now saw this. It is a Pypes 3" full exhaust with X pipe, and Pypes 18" case Race Pros.
 

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I would save yourself some grief and save and put a roller in it. Longterm it will pay for itself. I have replaced 7 board members solid flat tappets this year that all went down.
 

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I would save yourself some grief and save and put a roller in it. Longterm it will pay for itself. I have replaced 7 board members solid flat tappets this year that all went down.
Is that the destiny of all flat tappet cams today or just ones with extreme spring pressures?

And what do you recommend in a roller cam?

Thanks, Dan
 

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I would save yourself some grief and save and put a roller in it. Longterm it will pay for itself. I have replaced 7 board members solid flat tappets this year that all went down.

Well now, there's a group I have no interest in joining!


To be sure, flat tappets require you to be very "anal" about break-in procedures, valvetrain geometry, materials and lubricants. And even if you get it all right, there's a small chance of failure.

I even touched my lifter bores with a hone.

Sir, the UD 288/296 IS the correct cam for your application. I would not use it on the 107 LSA unless you want a wicked ragged idle. Be sure to install the cam advanced as the cam card says, typically on a 104 ICL. You'll make GOBS of power with that stick.

for the record my 67 ran out at 118.75 mph in the 1/4 mile with a UD 276/284F10 ( next size down, or two actually) stuffed in a 427 with nasty 074 castings on it. Actually the ports were dressed up well.

Crane lifters oil hole EDM'd by Crower. Isky 8005-a springs set up on the high side @ 1.905.

Also BTW, with those old heat dissipaters on there, the car was ALWAYS quickest, right off the highway. Run a 195 thermo to make the most power; old alloy likes it HOT!
 

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Again till I am blue in the face. A .024" to .028" EDM sinker hole in a lifter whether in the center or offset is not going to help nore is all the special oil and lubricants you want to use if the taper on the lobe won't spin the lifter nor the crown on lifter enough to spin.

For those that want to roll the dice go right ahead, it is your hard earned money but the better odds of survival are with a roller lobe, either hyd or solid.
 

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Discussion Starter #19
Well, I guess a Minigun would increase my chances for survival but since all I can afford is a 357 Magnum . . . . . just kidding :D
 

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427L88,

Thanks for the very correct suggestion. The UD 288/296F10/402A7LUN is an excellent choice for a 496 hot street car. At the right weight and with the right suspension, high 10s should be possible.
For more vacuum and more grunt at 2000 and below, getting one on a 112 LSA would help. I don't think that would affect the idle sound very much, if any.
A low-9 CR 468 made 561 BHP on ProMotorEngineering's dyno in the 1980s, and this was a conservative Stutska dyno, generally about 60 BHP under Westech's.
The 288/296F10 has gone 100,000 miles on the street in BBCs before, with the good old oil, and lifters with no oil-hole on the face.
Proper break-in for solid and hydraulic flat tappets is always a necessity.
Hydraulic roller cams on STEEL billets, with the EverWear Gear, eliminate the lengthy break-in procedure.
I believe BigRedL72 is running one of my hydraulic rollers in the lower 10s......

UDHarold
 
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