Harold,

I've just sent a 454 to the machine shop and need some advice on cam selection. The cylinder walls will get a cleanup, hopefully only .030 over. Crower crank, Manley rods, SRP pistons, 781 heads 2.25/1.88 valves, ported, victor JR intake, holley 950HP carb. Hopefully compressiobn will be in the neighborhood of 11-12:1 depending on decking, etc.

The car is a '78 Malibu two door, stripped out, roll cage, etc. For drag racing only. I haven't selected rear gears or a converter yet. It will run a TH400.

What solid cam would you suggest for this setup? I don't want to get into a roller, even though that would be nice. Thanks.

**Edit** I modified my setup and goals below, if you could take a look...thanks...

He'll need gearing, stall and what RPM you'll cross the stripe at Sean.

I don't know what they will be yet, but I've been told by some of you guys a 4500-5000 stall would work best, gears will probably be 4.10, and I'm guessing 6500-7000 across the line.

Sean,how big are the domes on those pistons?

I don't know yet. Are you thinking of the total lift?

Sean,the duration effects the piston/valve clearance..

Harold?

SS Sean,

Your 4.10 is too low for a NA BBC with only 460 CID.
It will depend upon your total car weight, and how fast you want to go.
A 3200lb 454 with a 5000SS converter and 5.13s will run 10.50s-10.60s with a 402B1LUN, 296/304 at .020, 263/271 at .050, .630/.630 valve lift, and 108 LSA.
Get that car to 2800lbs, same converter, 4.88s, and the 402B3LUN, 304/312 at .020, 271/279 at .050, same .630/.630 valve lift, and 110 LSA, and it will run low-10s, high-9s.
A 402B4LUN, 308/316 at .020, 275/282 at .050, .669/.675 valve lift,and 108 LSA can run 9.60s at 2600 lbs.
Your converter needs to be in the 4500-5000 SS range, rear gears around 4.88-5.13, to go throught the lights at 7500.
I await your response.....

UDHarold

See, Harold told you even bigger than we did.
Off the shelf JE/SRP's are 28ish cc or 48cc for a 454.
Which leaves you at 10.7 w/115 cc head or 12.2x w/122cc head. Assuuming zero deck ht 4.54 gasket .041 quench. My heads are 122 so I've already checked into this.
That link I posted was an article for a combo like yours with the 296/304 IIRC. They planned on race gas.

Thank you very much guys! It's been a rough week and a little good advice is MUCH appreciated!!!! smile.gif

In talking with the machine shop it sounds like 7500 is a huge amount of stress on a stock block, since they didn't come with the webbing the aftermarket blocks do. If I revised that rpm to something in the neighborhood of 6500-6800, would that change your cam recommendation? I'm sure it would. I just can't afford something like a Merlin block, and if I could, I'd make it a 502 anyway. Less rpm, more power. I think 65-6800 is a little more realistic on this ol' boys budget...Unfortunatley I'll have to do the best I can with what I've got.

I'm running similar combo in my Camaro. CompCams 308AR .651 lift, Ross 12.5 pistons, 468ci with Holley 950hp. and have run 10.69. Car is in shop having professionally done ladder bar suspension. Am hoping to to reach 10.30's! Oh yeah! I run thru traps at 6800rpm with 456's! I think Harold's suggestion for the .630 cam would work well for your combo! graemlins/waving.gif

Thanks, Bob. smile.gif

Sean, this is a bracket car right? Meaning, I don;t mind zinning up a street rat to 7-ish once in a while, but for a full-duty bracket car, why would you want to put it through that two dozen times a week?

For a bracket car, I'd prefer to use the mid range torque output of the rat and gear accordingly. Say 4.10's with a tight 8" converter with a mill design to produce max output at 4000-6200.

In the right hands those setups are running 10's. Hit it with 250 shot, and it shoud run 10's without the years of tuning it might take you N/A. and the motor should like life better at 6200 than 7200 for sure, esppecially with the added cyl pressure of an oxidant like nitrous.

But, I'm not a racer, so, fwiw.

I agree with you, Gene. I'm revising goals not only based on longevity, but also budget. As I mentioned in another post I scored a complete 454 with 5,000 miles on it for $1,600. It comes with a new RPM airgap, and new chevy valve covers. So, now that I've picked up this motor I've gotta live with what I got. Whether the motor has forged or cast crank/rods/pistons (unsure at this point), I think this will work for me.

I was looking seriously at a 454 buildup done in the Sept '01 Carcraft, and with a mild hydraulic they were able to get 533HP@5600/565TQ@4200 out of this motor, using the Comp Cams XE274H-10. 230/236 (.050), .552/.555, 110 LSA. They did use Edel alum oval's on it, but 781's would work well, not quite but as well, but good with some porting.

If the 781's that come with the motor aren't what I need I'll pull the same 781 heads off my Chevelle SS. I need the 2.25/1.88 valves, roller tipped rockers, porting on the short side runners and a little bowl blending. Either way, I've got a set of heads to use.

I've got a Mallory Comp 9000 distributor, and a blaster coil, a Mallory fuel pump/filter/regulator, and a Holley 950HP to use. I'll run a CSI elec water pump, and a two fan system. I'm picking up a S-10 manual steering box, which is a direct bolt in. I've also got a line on a set of Hooker super comp headers, but I'm not sure if this is what I'm going to end up with. The radiator will be aluminum with trans cooler and oil cooler.

The rear's going to be Ford 9", and I've got that too. I just need to settle on a gear at this point. I'm going to run the BMR adjustable control arms, new springs, 90/10 shocks. I also have a plan to mini-tub the rear frame rails to fit 28x13.5 M/T tires under it. It currently fits 28x10.5's, which are just fine, as is. I've got the crossmember for the TH400, which has cutouts to run the true dual exhaust up close to the pan. I figure a 2.5"-flowmaster-3.0" exhaust will be perfect.

Interior will be gutted, but I think the dash and door panels will stay. Two race seats, 12 point roll bar, and a B&M shifter, and a plethora of gauges to monitor everything.

I'm very interested in running a solid for a little more 'area under the curve', and was looking at Lunati's 402A3LUN, 276/284 (adv), 243/251 (.050), 0.586/0.600, 110 LSA. RPM in 2500-6800 range.

I seem to recall more than a few guys here running this cam, or similar grind, with good results. I think the power comes on at a more reasonable rpm, good for the launch, and carries through the range for the long end.

Any thoughts on this setup, or experience with this cam? Thanks...

shawn,
this is the combo on our old race car. keep in mind it was NOT fine tuned. 65 malibu, 3300#'s with driver. stock ls-7 crate motor except for weisco 12.5-1 pistons. stock deck height from factory and heads were not cut or ported and just had a 3 angle valve job. cam was a lunati 40227 .620-.620 gross lift. topped with a team-g intake and old carb shop 920 cfm carb(bought from summit). it was hooked to a glide with a B&M 5000 stall converter and brake. rear was a 12 bolt with old ladder bars welded on and 4.56 gears. 29" tall 10" wide slicks. car also had a single blue pump and 1/2" fuel line.
no msd stuff was used at all. just a unilite and blaster coil. we'd leave off the brake, shift at 7,000 and cross the line at about 7500 rpm. best et was 10.65@ 128. we only raced at test and tunes and did not fool much with it. good luck mike

Sean, don't know about a race cam, but that cam is something else on midrange punch! If you're really shifting at the same rpms I do ( 67-6800 or so), you might go one size bigger.Something along the lines of Harold's "stock" bracket cam, the 288/96. With the nitrous, you might setle for a 110lsa, unless you'll get wild with it later on.

For a small-port 460 shifting at 6200 or so the 276/84 would be fine I think. But if you gear this combo to run closer to a 7K shift point, it'd be too small. 288/296 or the class of cam Harold specs for you.

Originally posted by ratuned:
shawn,
this is the combo on our old race car. keep in mind it was NOT fine tuned. 65 malibu, 3300#'s with driver. stock ls-7 crate motor except for weisco 12.5-1 pistons. stock deck height from factory and heads were not cut or ported and just had a 3 angle valve job. cam was a lunati 40227 .620-.620 gross lift. topped with a team-g intake and old carb shop 920 cfm carb(bought from summit). it was hooked to a glide with a B&M 5000 stall converter and brake. rear was a 12 bolt with old ladder bars welded on and 4.56 gears. 29" tall 10" wide slicks. car also had a single blue pump and 1/2" fuel line.
no msd stuff was used at all. just a unilite and blaster coil. we'd leave off the brake, shift at 7,000 and cross the line at about 7500 rpm. best et was 10.65@ 128. we only raced at test and tunes and did not fool much with it. good luck mike 7500 RPM's on a stock bottom end? :eek:

Gene, I think I understand what you're saying...if a shift comes at 6800 you've gotta give it some more RPM range to compensate for the automatic delay before the actual shift, correct? That makes sense to me.

Sean,you'd be suprised what a "stock" bottom end could handle..especially an LS7.those motors had all the good stuff..and those lightweight Weisco pistons sure help alot!

sean,
it was stock except for the weisco pistons and a fluidamper. remember, you are only there for a short period of time. it was the best most simple motor we ever used. we later changed to ported 990 heads and a crane solid roller and a davinci dominater and only picked up 2 tenths. also remember we are only test and tune hackers. i wanted to send the carb back to davinci to have it recalibrated because it came off a full race blower motor. we also never raced on an excellent surface. i believe that the car could have possibly run another 1-2 tenths quicker if we wanted to race more than 5 times a summer. trust me when i say your goals should be easily achievable. even with the glide the car would put about 6" of air under launch and always ran consistantly within half a tenth. very little maintenance with the motor. good luck mike

as for the stock bottom end we also ran a 12-1 427 motor in a camaro. it only had 2 bolt mains with a stud kit and still had the heavy trw pistons. we still trapped at 7500 rpms with a solid cam with no botton end problems. good luck mike

Good info...thanks, ratuned.

SS_ Sean, A word of caution here. Be sure the top of the block is notched to clear the big valves or you will suffer the same fate as Chris454ss who now has a large pile of broken parts because ALL his valves collided with his pistons and block! Piston to valve and block to valve clearences are critical.

Caution noted...The motor will be going to the engine shop for this reason. As soon as I have the heads in hand I'll take it in and have it set up properly.

Originally posted by UDHarold:
SS Sean,

Your 4.10 is too low for a NA BBC with only 460 CID.
It will depend upon your total car weight, and how fast you want to go.
A 3200lb 454 with a 5000SS converter and 5.13s will run 10.50s-10.60s with a 402B1LUN, 296/304 at .020, 263/271 at .050, .630/.630 valve lift, and 108 LSA.

UDHarold Harold,

With due respect, either your estimates are ultra conservative or this is the wrong cam for his application. My little solid roller (XR286 .660 - 248/254) 10.3:1 460 pushes my 3,700 sled to 10.60 at 127mph with a 4.10 gear. I go through the lights under 7k even with a converter that flashes to 5,300. Maybe a little more lift and lighten the bottom up some?

I also think a good 460 C.I. Big block can push your car 10.6's without using ultra low gears if you have good exhaust.(3" with Borla mufflers work very well) My sons Chevelle ran 10.48 with this setup in a 481 @ 3500 lbs. and only had 4.10 gears. We tried 4.33 gears once and slowed down 1 tenth and lost 2 MPH.