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Discussion Starter · #1 · (Edited)
Hello everyone. Ive been thinking about doing a cam swap lately and I want to upgrade to a roller cam for my street/strip chevelle. Here is my combo:

454, stock bottom end, ARP fasteners
.30 over forged speed pro pistons. 9.7:1
Edelbrock Performer RPM aluminum heads. 2.19 1.88
Comp Cam XE274
Edelbrock RPM Air Gap intake
Holley 750 VS
2700 Hughes Converter
4.10 Gears

This is the cam I have been looking at
http://www.summitracing.com/parts/LUN-10221LK/

What are your opinions?
 

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Your compression ratio is low IMO.
Also, you might want to swap that carb for a mechanical secondary.
The reason for a big cam is to get more air into the engine.
When you swap, get a bigger carb too. Try 800 cfm mechanical.
The roller allows you to run more aggressive cam lobes than a flat tappet.
That is the reason for rollers.
You have lots of gear and aren't letting the engine breath.
 

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Needles to say a 454 likes to rev. If your Crank, Rods & Pistons are forged you might consider a Solid Roller with a Stud Girdle and reach for 6800+ rpm considering the cost isn't that much more over a HR Set Up. The 80511-1 Holley 830DP Annular booster will work great; however a STD Holley 850Dp Down Leg will work. For a 9.5 to 10.2:1 Static look at the Lunati 502A1 or A3 with say Com Cams 933 Springs. [600+ Hp] Use either Crower Hippo or Isky EZ Rollers. 7/16" Push Rods and either Harland Sharp or Pro MAG Rockers are a Must with 2" ARP-235-7207 or similiar Rocker Studs for extended Poly-Locks in order to mount the Girdle. If your mostly drag I might consider the LUN 60230 or 31 SR Profiles. If you choose a Lunati Billet ensure you spend the extra $30 for the Pressed on Cast Ever-Wear Dizzy Gear.

9.7:1 Static with what? N0 Decking and a .038" Composite Gasket? Consider 0-Decking and run the .038" Gasket and you should be close to a 10.2:1 Static with an ideal quench.

If the Crank and rods are NOT forged, I would stick with a Hydraulic Flat tappet, keep the revs below 6400 rpm and run something like the Comp Cams XM278HR-12 with 925 Springs where a Holley 750 to 850 Dp would work just fine. [500+ Hp]

To me the 396, 427 & 454 haven't much use for a HR. A HR is great for lower revving large displacement mills like 496 and up. Your not going to get any more revs with a HR over HFT as the Hydraulic lifter itself is limited along with lower spring rates compared to SFT & SR.

Either way there is considerable expense for that Roller SetUp, extra 1000rpm + 100 Hp. Makes me wonder why I ever went SR considering how well that XM278H-12 works on the Street & Cursing. Legally, you can never use that 500hp on the street let alone 600+Hp.

That XE274H-10/9.7:1 Static looks just fine to me on Pump Gas with an Auto and them 4:10 Gears for Street/Strip but NOT much of a Cruiser - Whats your Top Speed 115mph and rung out just before the 1/4 & another 1/4 to shut her down. If your a 1/4 mile chaser - You might keep what you have be better off with 3.73 gears with perhaps with that XM278H12 Cam. Those 4:10's pretty well require a higher revving Mill with either a bigger SFT or SR cammed 10.5:1+ Static MK IV in the 1/4. Then your approaching 10 Sec and require a Roll Cage - LOL

I got rid of my 4:10's long ago & run either 3:31's or 3:08's with a 10.25:1 Static SR (502A1LUN) 454 MK IV/M21 in a 70Z - YES my 1st gear is Tall & I'm a second or 2 slower in the 1/4 coming out of 3rd @ 6800rpm and 120mph with another gear to boot but I'm a Country Boy & Love the Open Road ;o)

Good Luck and hope I've helped.
 

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Let me share some insights
I have small domed forged slugs so I had to go closed chamber oval heads. These got the big valve and bowl blend treatment by Terry Malm. Needed more CR so went 0-deck and .039" head gasket. Thumb/trk rods, ARP bolts, forged crank, and studded 2-bolt mains. CR comes out at 10.5:1.

I thought a lot about the cam...this is a true street-strip 70 Elky that I take on errands, cruise 2 hours to see friends, etc...3.42 gears and a 3000 B&M stall. I saw the benefits of roller but was willing to sacrifice extreme power for reliability so no extreme lift of mega-mondo spring pressures. I worked out a 237/245* .601/.600" 110 lsa cam, billet core HR from DELTA CAMSHAFT in Tacoma. That's tight, Hyd Roller. To this, I added solid roller lifters, have the roller rockers down at .010" lash in this vid. Stagger jetted 800DP on top of the RPM intake.

http://www.youtube.com./watch?v=sUI7U5I0sTY

Only three outings in 2010 before the Elky went to the paint shop.
Numbers below...
More power to be found, looking at a bigger carb, 800cfm isn't enough, should mph at 114.8, so far only 113.26

Comparing this to your engine and vehicle...
your cam is too small for your gearing.....you'll run out of nutz..
need a bigger cam for the gears and more CR to support the bigger cam as Z15 said. Unless you are endurance racing, I do not see the need for 7/16" pushrods, but do get some quality PRs for sure.
 

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Whatever roller cam you choose,get it on the GEN6 platform so you can use a retainer plate instead of messing with a cam button.
 

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Although pricey, I use a Donovan Cam Gear Drive to lock my Roller in with a .004" end play. The Donovan Unit also makes it easy for degreeing and Cam installation FT or Roller. It's a little noisy until the Engine reaches Temperature but other words verily quiet at Idle scarcely heard above the Solid Lifters and NOT noticeable at all at cruise.

A GEN VI Cam does not have the Fuel Pump Lobe and you will require an Electric Pump.

I recommend you stack approx 3 Lube Impregnated Wear Plates with 1mm Holes drilled through them for Kick Back rather then using the Torrington Unit. I drill a 1mm hole through the Blocks Front Cam Boss behind the Wear Plate into the Cam Journal Oil Feed to Lube the Wear Plate and drill another 1mm Hole in the Front Psgr Tappet Gallery Plug to oil the Cam Gear or Chain, whatever.
 

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A GEN VI Cam does not have the Fuel Pump Lobe and you will require an Electric Pump.
The BOLD above is an inaccurate statement, My ZZ502 GEN6 cam DOES have a fuel pump lobe & is using it to run my MkIV 454.

GEN6 cams DO have a lobe GEN5 do not.

Either that or my Holley 750 has a hell of a suction.
 

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OK - My Laxness and Your Relative Info - But ;o)

Although I have little experience with GEN V & VI GM Roller Blocks, I've always understood "If the cam he has is a GM Gen V or Gen VI Camshaft, they usually DO NOT have a fuel pump cam lobe." I do believe aftermarket cams can be had with or without the Lobe.

Yes the Lock Plate with a Stepped nose cam (similar to Chrysler) is in my opinion over the Button/Wear Plate is better for an Anti-Cam-Walk Device but you also require a Special Timing Gear set. Almost all BBC's are fitted with Bolt holes to mount a Cam Lock Plate. You also have to consider that the Gen V & VI Blocks have true aligned Lifter Bores for Roller Lifters which about NEGATE Cam Walk.

North American Engine MFGr's where never concerned about Lifter Bore Alignment relative to Cam-Walk-Forces of a Retro-Fitted MK IV as the Machined "Beveled" Lobe of the FT Cam held the Cam in position. Consequently, if you notice a Push Rod NOT Spinning in a FT Mill you can suspect a Bad Cam Lobe or Lifter.

I "personally" don't like Buttons for forward walk or Torrington Wear Plates in Retro-Fitted FT (MK IV) mills. It would have been nice to had the Lifters Bores Aligned Bored when Retro-Fitted, which is the reason I still run a Hi-ZDDP content Oil to protect the Lifter Roller Needles from Cam Walk Forces, even if there HIPPO or EZ (Think about 200/500lbs x 16 or better springs resting on them Needles, Miss-Aligned & Driving the Cam Forward - Chevy Phenomena) - NOTE my previous concern RE: Oiling Mods for Timing Gear or Chain and Wear Plates - By the way, 1mm = approx .040" (HSS #60) bit.

You can use lower ZDDP oil if the lifter bores have been aligned and fitted with large bore lifters in a Retro'd FT Mill or start with with a modern block designed for Roller Cams.

After 45 years of Engine Building & Observation, these are my Findings and should NOT be considered Gospel without an Argument, which I appreciate, and will Respond without Malice BUT with Intensity; or else, we would not be here ;o)

For-Mike-A: Be Aware, Comp Cams Roller Cams Part # Suffixed with an "8" is NOT Billet but a Cast Roller and will not handle much more then 150/450lb Springs for a HR and say 190/490lbs for a SR Cam - They work when set up correctly but don't expect the Revs.
 

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yes, stepped-nose GEN VI type core is the way to go
I had a hell of a time with my old 'dumb school' thrust button.

re 3.42s
I have 3.36 and wide ratio (2.52) M-20 in the 68 427 Vette; good compromise between power and sane cruising. So when it was time to ditch the Elky's 2.56 gears, the 3.42 was the closest match. Most of the Elky's outings are 15 miles from home; Bonney Lake, Puyallup, Olympia for a burger... then there are the outing days, cruise, see a friend, do a few errands. Big trips are two hours to see FRYNTYR and the N of Seattle guys.
The longer trips, the mpg seems to be around 14,,,,,
 

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Discussion Starter · #13 ·
Yikes I need more compression. I thought 9.7:1 was decent? I know the block was decked, and im not too sure about the gasket thickness. The guy that did the machine work is the one that figured my CR. Is there a way to tell how much a block has been decked? Buying new pistons is something I would like to avoid at all costs. Im pretty sure the crank and rods are cast, but im not positive. I know the engine came out of a mid 70s motor home :p.

11s is where I want to be. As long as I can get an 11.9 at the track ill be happy.

So.. assuming that I keep the compression as is what would be a good cam choice?

And if there is a way I can bump up the compression to over 10:1 without changing pistons then what would be a good cam choice?

Thanks
 

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if there is a way I can bump up the compression to over 10:1 without changing pistons
Cast Rotating Assembly - With Out Spending Big Time, read my earlier post to reach 10.2:1 Static perhaps 10.4 by 0-Decking with a .038" Head Gasket and Quench. Consider the XM278H-12 Cam/CC-925 Springs with 3.73 Gears; MAX RPM 6400 and 500Hp, rung out by the 1/4 at approx 118+mph with a Camaro - Heavier Chevelle maybe 6200 rpm & 115mph - Keep the Pistons (Cast or Forged) & run pump gas ;o)

Even Swap 4:10 Gears & Carrier for 3 Series Carrier and 3.73's but you pay misc parts and labor.

Total cost around $1200 (doing the assembly yourself), $2,400 paying others and can you trust them? A 750 Holley Dp should do the job on top of your Dual Plane Eddy Air Gap.

Your Garage is your Maserati; hopefully you have one, if not it's "HELL".

Can't Help you much more - Good Luck.

There's the 1/4 & then there's the Road Warrior ;o)

PS: Check Out P. Kelley's DCR Calculator found here: http://www.empirenet.com/pkelley2/DynamicCR.html


 

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Discussion Starter · #15 ·
Z15, I definately respect your opinion but I have to ask, whats wrong with 4.10 gears, 10:1, and a cast rotating assembly? I dont think ill be running out of rpms by the end of the 1/4. I dont think ill be risking the bottom end if I keep it under 6500. I understand with more duration I should need more compression and roller cams are designed to get away with more lift and duration.

So say if I get a roller cam with a duration in the 280s, compression above 10:1 with a .38 gasket and decking and keep the cast bottom end cast, would that be a good combo for the 4.10s?

Also, the block has already been decked. Im just not sure how much. What is it mean to have it 0 decked? Is there a way to measure the deck height so I know for sure?

The rearend is new, along with the eaton posi and gears. I am not willing to swap them out for 3.73 at this point. I want to throw some money into it, but I dont want to undo everything I just did and paid a large amount of money for.
 

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Mike,

Not saying what you have WON'T work, just advising as you requested.
Your cam in a 402 or 427 with some more CR and the 4.10 would be a screamer...
You put the same cam in a midling CR 454, it is a mid-range beast.

Your "cast rotating assembly" is fine, very fine...let's look
Forged SpeedPro slugs....plenty good by me
All BBC rods are FORGED, even the regular rod is strong-enough, HT/Trk/thumb rods are better,,,,got pics of the build? You said ARP fasteners...you are talking rod bolts, right? If you got 'em, awesome! Plenty good, the real weak link is the factory rod bolt.
Cast crank? Great stuff to 600 horse and 6200 rpms, no problem. 2-bolt main bottom end is strong enough for most anything sane-enough for street duty.

With Eddy 110 cc heads and 9.7:1 CR, I conclude you have the short dome pistons. Build sheet/receipts should have a piston number.

Factory built BBC engines have pistons at .023" DITH 99% of the time from my years of playing with the Fat Boys. Performance engines in the day got .020--.022" shim head gaskets developing an average quench of .043--.045".

People do run shim head gaskets with Aluminum heads, I'd prefer not to. Your block was decked....no way to tell if it was 0-decked unless your builder kept a record/receipt or you measure. Sorry, gotta remove a cylinder head.

You could run a shim head gasket on your fresh cut deck...if the pistons are DITH and/or Shim head gasket plus shave the heads

You could have the heads shaved...if the pistons are flush/0-decked


9.7:1 is not bad at all...never said that. You can run a bigger cam in support of your 4.10s. You can advance the cam a few degrees...the engine will think it has more compression.

Hydraulic roller tappet
Basic Operating RPM Range 1,800-6,200
Duration at 050 inch Lift 232 int./242 exh.
Advertised Duration 278 int./288 exh.
Valve Lift with Factory Rocker Arm Ratio 0.575 int./0.575 exh.
Lobe Separation (degrees) 112

My power brakes work decently with 237/245* .601/.600" 110 LSA
I think your aftermarket heads would like the extra lift

Maybe VORTECPRO may have a recommendation...
 

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OK keep your 4.10's but NOTE that the CC-XM278H-12 (Designed for 9.5 - 10.2 Static Compression) has a very similar profile as that expensive Lunati 10221LK HR you where looking at.

What I and other members have been saying is that with 4.10's you will more then likely run out of steam before reaching the end of the 1/4 where 3.73's will keep you in the torque range. I'm saying the XM278H-12 stands the best chance of getting you there with your present engine/gearing combination for least cost.

Believe me the Comp Cams XM278H-12 is one Hell of a HFT MK IV Cam, especially for Heavier rides like the Chevelle with a 9.5:1 Static BBC. Don't let that XM (Extreme Marine) ID "SPOOF" you.

To Top it all off, the cam has one of the BEST Sounding Exhaust NOTES for any Enthusiasts ears.

With 4:10s you need 6000rpm shifts (Muncie) with a BBC to power through to the end of the 1/4. As you have an Auto, I'm giving you the benefit of Hope which that XM278H-12/CC-925 Springs can deliver along with ARP Rocker Studs mounted with Harland Sharp Rockers.

To simply put it: "Your Ride (Great Combo at that) can't go any faster on pump gas and it's all within a 1/4"

I'm predicting 117MPH in the Low 12's - But then again, I'm a Road Warrior with a 11 Sec quarter (expensive 7000rpm MK IV & Lighter 70Z Ride) with another gear to Boot and fight for traction, in all gears, with P295x15 BF Radial T/A's, praying I don't break something when I floor it - 7 years with this mill and hanging in. :eek:
 

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Discussion Starter · #18 ·
I looked through my receipts, which is not a pleasant experience btw, and I found the machine shop receipt and unfortuantely it does not mention how much the block was decked. It just says, "decked head surface."

Also, I remember not being sent a receipt for my pistons from summit. Either way, if I do go into the engine, the heads are coming off.

The reason why I want a roller is basically the same as everyone elses. I want insurance, peace of mind. I like the idea of the reliability and worry free nature of the roller cam. I understand that FT cams still perform in BBC but I want a roller. I might have a flat cam on my hands right now. I havent had time to look into it but, it sure sounds like its going flat to me.

Thanks for the aweome advice. This thread was definately interesting and educational. Ill bring this thread back up in about a week or so and let you guys know what I find, or decide to do.

I know everyone likes pictures. Here is a pic of the slug.


Uploaded with ImageShack.us
 

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my shortie dome slugs

 

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If you have your summit customer number, (should be on your catalog) you can go on their website and see all your past orders with them, and figure out exactly which pistons you have.
 
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